Tech Terms

C

C C is a general-purpose, high-level programming language. Created at Bell Labs in the 1970s, its developers first used it to write programs for the Unix operating system. C is very efficient at using a computer's memory. It also gives programmers more direct access to a computer's hardware than other high-level languages. For those reasons, it is now widely used to write operating system kernels and device drivers. C is an early example of a structured programming language, which divides a larger program into smaller modules or functions. Structured languages are easier to manage and reduce the complexity of the program's source code. It is also a compiled compiled language that requires a program's source code to be compiled into machine language before it can run. Since its introduction, C has inspired other programming languages. C++, Java, Objective-C, and C# are object-orientated languages heavily influenced by C. Many other languages base their syntax on C, including JavaScript, PHP, and Perl. Updated March 21, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/c Copy

C#

C# C# (pronounced "C Sharp") is a programming language developed by Microsoft. It was introduced in 2002 with version 1.0 of Microsoft's .NET Framework. Since then, C# has gone through several revisions, corresponding with each .NET update. Today, it is one of the most popular programming languages for creating Windows programs and web applications. C# is a derivative of the C programming language and is similar to C++. It uses the same basic operators as C++, is object oriented, case sensitive, and has nearly identical syntax. However, there are several differences between C# and C++. Below are just a few examples: Arrays in C++ are pointers, while in C#, they are objects that may include methods and properties. The bool (boolean) data type is not recognized as an integer as it is in C++. The keywords typedef, extern, and static all have different meanings in C# than they do in C++. C# switch statements do not support fall-through from one case to another. Global methods and variables are not supported in C#, while they are in C++. Most importantly, C# is designed specifically for Microsoft's .NET Framework. This allows developers to take advantage of all the features offered by the .NET API. However, it also means C# applications can only run on platforms that support .NET runtime, such as Windows, Windows Server, and Windows Phone. In order for programs written in C# to run on other platforms, the code must be compiled using a conversion tool like Microsoft .NET Native. NOTE: The name "C#" comes from the musical note "C♯," implying it is a step up from the original version of C. The ♯ symbol is also comprised of four plus signs, which may imply C# is more advanced than C++ as well. Updated June 4, 2014 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/c_sharp Copy

C++

C++ C++ (pronounced "C plus plus") is general-purpose programming language, created as an extension of the original C language. It uses nearly identical syntax to C but adds new features for object-oriented programming. It also includes more advanced memory management features, like dynamic memory allocation, and a more comprehensive standard library of pre-written functions. Introduced in 1985, C++ is still one of the most widely used programming languages for developing software. It retains many of the low-level capabilities of C that allow developers to quickly and efficiently access the computer's hardware and memory. This makes C++ a useful language for developing operating systems, embedded IoT software, and video games. Since C++ is an extension of the original C language, the two languages share most of their syntax. Like C, C++ is a compiled language that requires a program's source code to be compiled into machine language before it can run. Both are structured programming languages that divide programs into small functions or modules, and they share the same control structures like loops, if-else statements, and switch statements. Updated March 14, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cplusplus Copy

Cable Management

Cable Management Cable management is the organization of cables connected to electrical devices. This includes power cables, network cables, audio/video cables, and many others. Managing cables is a key aspect of a clean and safe home or work environment. Electrical devices often require multiple cables. For example, a desktop computer may require a power cord, Ethernet cable, and multiple USB cables for peripheral devices. A home theater system may include multiple power cables, as well as A/V cables for HDMI and analog audio connections. The resulting pile of cables, if not managed properly, can easily become a tangled mess. Cable management offers several benefits: It provides a cleaner workspace or living area. It makes it easier to add or remove devices and cables. It protects cables from crimping or other damage. It prevents cables from disconnecting unexpectedly. It limits interference from other cables. Cable management may be as simple as a tying a few cables together with adjustable cable clips. This type of cable management is often all that is required for a home computer setup. In some cases, a cable sleeve or a cable cover below a desk may help move cables out of the way. Managing cables can also be a complex process. For example, network engineers may need to organize hundreds of network cables from a server rack that connect to power outlets or network switches. This type of organization requires choosing the right cable length and correct cable management sleeves so that cables can be easily added or removed. Regardless of the application, cable management is an important part of any electronic setup. Simple cable management accessories, such as cable ties and cable sleeves, can turn a tangled pile of cables into a clean and organized space. Updated September 17, 2018 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cable_management Copy

Cable Modem

Cable Modem A cable modem is a peripheral device used to connect to the Internet. It operates over coax cable TV lines and provides high-speed Internet access. Since cable modems offer an always-on connection and fast data transfer rates, they are considered broadband devices. Dial-up modems, which were popular in the early years of the Internet, offered speeds close to 56 Kbps over analog telephone lines. Eventually, DSL and cable modems replaced dial-up modems since they offered much faster speeds. Early cable modems provided download and upload speeds of 1 to 3 Mbps, 20 to 60 times faster than the fastest dial-up modems. Today, standard cable Internet access speeds range from 25 to 50 Mbps. On the high end, Comcast offers an "Xfinity Extreme" service with speeds up to 505 Mbps. Most cable modems include a standard RJ45 port that connects to the Ethernet port on your computer or router. Since most homes now have several Internet-enabled devices, cable modems are typically connected to a home router, allowing multiple devices to access the Internet. Some cable modems even include a built-in wireless router, eliminating the need for a second device. NOTE: While "cable modem" includes the word "modem," it does not function as a traditional modem (which is short for "modulator/demodulator"). Cable modems send and receive information digitally, so there is no need to modulate an analog signal. Updated March 29, 2014 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cable_modem Copy

Cache

Cache Cache, which is pronounced "cash" (not "catch" or "cashay"), stores recently used information so that it can be quickly accessed at a later time. Computers incorporate several different types of caching in order to run more efficiently, thereby improving performance. Common types of caches include browser cache, disk cache, memory cache, and processor cache. Browser cache - Most web browsers cache webpage data by default. For example, when you visit a webpage, the browser may cache the HTML, images, and any CSS or JavaScript files referenced by the page. When you browse through other pages on the site that use the same images, CSS, or JavaScript, your browser will not have to re-download the files. Instead, the browser can simply load them from the cache, which is stored on your local hard drive. Memory cache - When an application is running, it may cache certain data in the system memory, or RAM. For example, if you are working on a video project, the video editor may load specific video clips and audio tracks from the hard drive into RAM. Since RAM can be accessed much more quickly than a hard drive, this reduces lag when importing and editing files. Disk cache - Most HDDs and SSDs include a small amount of RAM that serves as a disk cache. A typical disk cache for a 1 terabyte hard drive is 32 megabytes, while a 2 TB hard drive may have a 64 MB cache. This small amount of RAM can make a big difference in the drive's performance. For example, when you open a folder with a large number of files, the references to the files may be automatically saved in the disk cache. The next time you open the folder, the list of files may load instantly instead of taking several seconds to appears. Processor cache - Processor caches are even smaller than disk caches. This is because a processor cache contains tiny blocks of data, such as frequently used instructions, that can be accessed quickly by the CPU. Modern processors often contain an L1 cache that is right next to the processor and an L2 cache that is slightly further away. The L1 cache is the smallest (around 64 KB), while the L2 cache may be around 2 MB in size. Some high-end processors even include an L3 cache, which is larger than the L2 cache. When a processor accesses data from a higher-level cache, it may also move the data to the lower-level cache for faster access next time. Most caching is done in the background, so you won't even notice it is happening. In fact, the only one of the above caches that you can control is the browser cache. You can open your browser preferences to view the cache settings and alter the size of your browser cache or empty the cache if needed. Updated June 24, 2021 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cache Copy

CAD

CAD Stands for "Computer-Aided Design." CAD is the use of computers to create 2D and 3D designs. Common types of CAD include two-dimensional layout design and three-dimensional modeling. 2D CAD has many applications, but it is commonly used to design vector-based layouts. For example, architects may use CAD software to create overhead views of building floor plans and outdoor landscapes. These layouts, which contain vector graphics, can be scaled to different sizes, which may be used for proposals or blueprints. 2D CAD also includes drawings, such as sketches and mockups, which are common at the beginning of the design process. 3D CAD is commonly used in developing video games and animated films. It also has several real-world applications, such as product design, civil engineering, and simulation modeling. 3D CAD includes computer-aided manufacturing (CAM), which involves the actual manufacturing of three-dimensional objects. Like 2D CAD drawings, 3D models are typically vector-based, but the vectors include three dimensions, rather than two. This allows designers to create complex 3D shapes that can be moved, rotated, enlarged, and modified. Some 3D models are created exclusively of polygons, while others may include Bézier curves and other rounded surfaces. When creating a 3D model, a CAD designer may first construct the basic shape of the object, or "wireframe." Once the shape is complete, surfaces can be added that may include colors, gradients, or designs that can be applied using a process called texture mapping. Many CAD programs include the ability to adjust lighting, which affects the shadows and reflections of the object. Some programs also include a timeline that can be used to create 3D animations. Updated April 4, 2014 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cad Copy

CamelCase

CamelCase camelCase is a naming convention in which the first letter of each word in a compound word is capitalized, except for the first word. Software developers often use camelCase when writing source code. camelCase is useful in programming since element names cannot contain spaces. The camelCase naming convention makes compound names more readable. For example, myOneMethod is easier to read than myonemethod. Other examples of camelCase are listed below: newString; getNewString() myVariableName; The name camelCase (also "camel case" or "dromedary case") comes from the hump on a camel, which is represented by the capital letter in the middle of the compound word. A camelCase word may have one or more capital letters. camelCase vs PascalCase camelCase is similar to PascalCase, which capitalizes the first letters of all words in a compound word, including the first word. For example, myFunction() in PascalCase would be MyFunction(). Programmers may choose to use either font case when writing source code, since it does not affect the syntax. While each developer can choose his or her preferred style, some programming languages have standard naming conventions. For example, in Java, the following cases are recommended: Classes: PascalCase — class VectorImage {} Methods: camelCase — drawImage() Variables: camelCase — string newImageName NOTE: PascalCase is sometimes called "UpperCamelCase," while standard camelCase may be specified as "lowerCamelCase." In recent years, developers have moved away from these terms and use PascalCase and camelCase instead. Updated October 1, 2020 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/camelcase Copy

Camera RAW

Camera RAW A camera RAW image is an unprocessed photograph captured with a digital camera. It contains the raw image data captured by the camera's sensor (or CCD), saved in proprietary file format specific to the camera manufacturer. By default, most digital cameras process and compress photos as JPEG files immediately after capturing the image. The processing step automatically applies the appropriate color correction and the JPEG compression significantly reduces the file size. The result is an efficiently processed JPEG image. While JPEG images are suitable for most purposes, professional photographers and photography enthusiasts prefer to control over how each image is processed. Therefore, many high-end cameras have the ability to shoot in RAW mode instead of JPEG. The raw files are unprocessed, allowing the photographer to adjust settings like exposure, white balance, and saturation after the image has been captured. Instead of applying lossy JPEG compression, which reduces the image quality, RAW mode saves files either in a losslessly compressed format or in an uncompressed format. Because they use less compression, Camera RAW files take up more space than typical JPEG images. In fact, RAW files often require 5 to 10 times more disk space for each image captured. So you'll want to have a large memory card in your camera if you plan on shooting in RAW mode. Viewing Camera RAW Files Since Camera RAW files are not saved in a standard image format, image viewing programs may not recognize them. Even if a program supports the Canon RAW format, it may not recognize a RAW file saved by a newly released Canon camera. Therefore, camera manufacturers often include proprietary RAW photo editing software with their high-end cameras. Additionally, popular operating systems and software programs are regularly updated with support for new RAW formats. Common Camera RAW File Extensions .ARW (Sony) .CR2 (Canon) .DCR (Kodak) .DNG (Adobe) .ERF (Epson) .NEF (Nikon) .ORF (Olympus) .PEF (Pentax) .RAF (Fuji) .RW2 (Panasonic) Updated December 10, 2016 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/camera_raw Copy

CAN

CAN Stands for "Campus Area Network." A CAN is a network that covers an educational or corporate campus. Examples include elementary schools, university campuses, and corporate buildings. A campus area network is larger than a local area network LAN since it may span multiple buildings within a specific area. Most CANs are comprised of several LANs connected via switches and routers that combine to create a single network. They operate similar to LANs, in that users with access to the network (wired or wireless) can communicate directly with other systems within the network. A college or university CAN may also be called a "residential network" or "ResNet" since it can only be accessed by campus residents, such as students and faculty. The two primary benefits of a CAN are security and speed. Security Unlike a wide area network (WAN), a CAN is managed and maintained by a single entity, such as the campus IT team. The network administrators can monitor, allow, and limit access to the network. Firewalls are typically placed between the CAN and the Internet to protect the network from unauthorized access. A firewall or proxy server may also be used to limit the websites or Internet ports users can access. Speed Since communication within a CAN takes place over a local network, data transfer speeds between systems within the network are often higher than typical Internet speeds. This makes it easy to share large files with other users on the network. For example, it may take several hours to upload a long video to a colleague over the Internet, but the transfer may only take a few minutes over a CAN. NOTE: CAN may also stand for "Corporate Area Network" or "Controller Area Network." Updated November 23, 2018 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/can Copy

Caps Lock

Caps Lock Caps Lock is a feature on most keyboards that, while enabled, capitalizes each letter character typed on the keyboard. It allows you to type as if you were holding down the Shift key, but it only affects letters — numbers and punctuation keys are not affected. Pressing the Caps Lock key on the keyboard toggles it on, and it remains active until you press the Caps Lock key again. Pressing the Shift key while typing a letter allows you to enter a lowercase letter with Caps Lock enabled. The Caps Lock key is a toggle key found on almost all keyboards designed for Windows, macOS, Unix, and Linux — Chromebook keyboards lack a dedicated Caps Lock key and instead use a keyboard shortcut to toggle it. In most layouts, the Caps Lock key is found on the left side of the keyboard between the Tab and Shift keys. Many keyboards include an LED light on or near the key that lights up when Caps Lock is active, and some operating systems also show an on-screen indicator. The Caps Lock key on a MacBook Air keyboard Touchscreen keyboards on smartphones omit the Caps Lock key to save screen space. Instead, you can enable Caps Lock on iOS and Android devices by tapping the Shift key twice. To turn Caps Lock off, tap the Shift key again. NOTE: Since passwords are case-sensitive, and password fields obscure your password while you're typing it, Caps Lock can cause you to enter an incorrect password if it's accidentally enabled. Updated November 8, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/caps_lock Copy

Captcha

Captcha A captcha is program used to verify that a human, rather than a computer, is entering data. Captchas are commonly seen at the end of online forms and ask the user to enter text from a distorted image. The text in the image may be wavy, have lines through it, or may be highly irregular, making it nearly impossible for an automated program to recognize it. (Of course, some captchas are so distorted that they can be difficult for humans to recognize as well.) Fortunately, most captchas allow the user to regenerate the image if the text is too difficult to read. Some even include an auditory pronunciation feature. By requiring a captcha response, webmasters can prevent automated programs, or "bots," from filling out forms online. This prevents spam from being sent through website forms and ensures that wikis, such as Wikipedia, are only edited by humans. Captchas are also used by websites such as Ticketmaster.com to make sure users don't bog down the server with repeated requests. While captchas may be a minor inconvenience to the user, they can save webmasters a lot of hassle by fending off automated programs. The name "captcha" comes from the word "capture," since it captures human responses. It may also be written "CAPTCHA," which is an acronym for "Completely Automated Public Turing test to tell Computers and Humans Apart." Updated May 8, 2009 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/captcha Copy

Card Reader

Card Reader A card reader is a hardware device that reads and writes various flash memory card formats. Some computers (particularly laptops) may include built-in card readers, but they are more common on other devices like printers, scanners, digital cameras, and audio recorders. Computers without a built-in card reader can use external USB-connected card readers. An external card reader that uses USB-C can even connect to smartphones and tablets to allow them to transfer data to and from memory cards. External card readers often include multiple slots, each designed for a different type of memory card. SD and microSD cards are the most widely used, but other formats like Compact Flash, XQD, CFexpress, and Memory Stick cards are also commonly found on multi-card readers. A Lexar multi-card reader with slots for SD, CF, and Memory Stick cards Inserting a card into a computer's card reader automatically mounts that card's contents. Once mounted, it appears like any other disk connected to the computer and is accessible through File Explorer (on Windows) or the Finder (on macOS). Since most digital cameras use memory cards to save and transfer digital photos, your computer may even automatically launch photo management software to import photos when a memory card is connected. Like with any other type of removable disk, memory cards in a card reader should be unmounted (or "ejected") before you remove the card; this stops all read-and-write activity and prevents corruption of the card's data. NOTE: Since Windows automatically mounts memory cards once connected, a memory card containing malware could infect your computer. You should never connect an unfamiliar memory card to your computer if you're unsure of its contents. Updated November 27, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/card_reader Copy

Case-Insensitive

Case-Insensitive If something is case-insensitive, it does not distinguish between uppercase and lowercase characters. It is the opposite of case-sensitive, in which the case of each letter matters. Most search engines are case insensitive, meaning the case of the keywords does matter. For example, searching for "Microsoft Word" and "microsoft word" will return the same results. Case insensitive functions are able to match strings regardless of letter case. Usernames are also typically case-insensitive. For instance, when logging in to a website, the username field of the login is not case-sensitive. The password field is. So, while capital letters usually don't matter when entering your username, they are important when entering your password. Sorting Text Sorting algorithms are usually case-insensitive, meaning they treat "A" the same as "a." However, some functions use the ASCII value of each character, in which all uppercase letters come before all lowercase letters. In an ASCII sort, C comes after A, but before b. When sorting text values in a database, the sort order is determined by collation, a rule for sorting the data. The default collation is typically case-insensitive and based on the text's character encoding, which assigns a numeric value to each character. MySQL and other database engines support multiple collations, such as latin1_general_cs (case-sensitive) and latin1_general_ci (case-insensitive). While it is rare to use a case-sensitive — or "cs" — collation, it is possible to override the default "ci" collation if necessary. Updated August 20, 2022 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/case-insensitive Copy

Case-Sensitive

Case-Sensitive Case-sensitive means distinguishing between lowercase and uppercase characters. It is the opposite of case-insensitive, where the case of each letter is irrelevant. Case sensitivity has several applications in computer science, including matching and sorting textual data. 1. Matching A text-based search may be either case-sensitive or case-insensitive. If a search function is case-sensitive, searching for "example" will not match "Example" and vice versa. If the function is case-insensitive, the two terms will match. Most search engines and search functions are case-insensitive, meaning uppercase and lowercase letters do not matter in the search keywords. Case sensitivity also applies to authentication. When logging in to an app or website, the password is always case-sensitive. In other words, the login will fail if you enter "testpass" when the correct password is "TestPass". In most situations, the username is case-insensitive, though some logins require a username with the proper case. 2. Sorting Like searching, most sorting algorithms are case-insensitive. However, some programs support case-sensitive sorting, meaning the letter case affects the order of the results. If a case-sensitive sorting algorithm uses each character's ASCII value, then all capital letters come before all lowercase characters. In an ASCII-based sort, T comes before t, and also before a, b, c, etc. Other case-sensitive algorithms may only prioritize capital letters before their lowercase counterparts. So T would come before t, but after a, b, c, etc. Updated August 13, 2022 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/case-sensitive Copy

Cat 5

Cat 5 Cat 5 (short for "Category 5") is a type of Ethernet cable. It supports data transfer rates of up to 100 Mbps, or 12.5 megabytes per second. Cat 5 cables operate at a 100 MHz frequency and can extend up to 100 meters between connected devices. Each Cat 5 cable has eight internal wires, or four "twisted pairs." These pairs, which are color-coded, may be wired two different ways into the RJ45 connector. A Cat 5 cable with the same wiring on each end is a "patch cable," while one that is wired differently on each end is a "crossover cable." Category 5 Ethernet cables were commonly used for creating local area networks in the late 1990s and early 2000s. Since they supported 100 Mbps transfer rates, they were sufficient for 100BASE-T "Fast Ethernet" networks. In 2001, Cat 5e cables, which support 1000BASE-T (Gigabit Ethernet), began to replace Cat 5 cables. Today, most wired networks use Cat 5e cables and above. The low maximum data transfer rate of Cat 5 would create a bottleneck in most modern networks. While Cat 5 cables are only rated for 100 Mbps networks, many Cat 5 cables support data transfer rates over 100 Mbps. Some may even support speeds up to 1,000 Mbps. NOTE: "Cat 5" is shorthand for "category 5." Since there is no standard abbreviation, "Cat5" and "Cat-5" are also acceptable. Updated December 16, 2020 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cat_5 Copy

Cat 5e

Cat 5e Cat 5e (short for "Category 5 Enhanced") is a type of Ethernet cable. A Cat 5e cable has the same appearance and wiring scheme as a Cat 5 cable, but supports data transfer rates of 1,000 Mbps or one gigabit per second. Therefore, Cat 5e cables are sometimes called Gigabit Ethernet cables. Cat 5e cables operate on the same 100 MHz frequency as Cat 5 and have the same maximum length of 100 meters before requiring a router or powered signal booster. The primary difference between the two standards is that Cat 5 is only rated for 100 Mbps networks, while Cat 5e supports 1,000 Mbps networks. While the cables are nearly identical, Cat 5e cables have improved shielding that reduces crosstalk, or interference from adjacent wire pairs. Technically speaking, Cat 5e cables must adhere to stricter IEEE standards in regards to Near-End Crosstalk (NEXT) measurements, which are measured in decibels. The difference between Cat 5 and Cat 5e shielding is specific to the internal wires, not the outer sleeve, or "jacket." An Ethernet cable's outer jacket (designed for indoor, outdoor, in-wall, etc) has no bearing on the IEEE rating. In 2001, Cat 5e began to replace Cat 5 as the most widely used Ethernet cable standard. Today, nearly all wired networks use Cat 5e cables or higher. Updated December 31, 2020 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cat_5e Copy

Cat 6

Cat 6 Cat 6 (short for "Category 6") is an Ethernet standard. It operates at 250 MHz and supports data transfer rates of 10 Gbps. The maximum speed of Cat 6 is 10x faster than the previous standard, Cat 5e. From the outside, Cat 6 cables look identical to Cat 5 and Cat 5e cables. They use the same RJ45 connectors and are backward-compatible with Cat 5/5e Ethernet networks. Internally, Cat 6 cables retain the same "twisted pair" wiring scheme with eight internal wires. The primary difference between Cat 6 and Cat 5 is that Cat 6 operates at 250 MHz, while Cat 5 and 5e operate at 100 MHz. The higher frequency enables Cat 6 cables to transfer data more quickly. Cat 6 vs Cat 6a Similar to Cat 5, Cat 6 has a variant with performance improvements. The variant is called Cat 6a (rather than Cat 6e). Cat 6a operates at 500 MHz, twice the frequency of Cat 6, but supports the same maximum data transfer rate of 10 Gbps. The difference is that Cat 6 can only transmit data at 10 Gbps for 55 meters (180 feet), while Cat 6a supports 10 Gbps for 100 meters (328 feet). A Cat 6 cable will still work over 55 meters, but the speed may decline. In order for Ethernet cables to transfer data at full speed over long distances, a router or powered signal booster must be placed every 100 meters. While Cat 5e was the most popular Ethernet standard for nearly two decades, many modern LANs now use Cat 6 or Cat 6a cables. Even if the network equipment does not support 10 Gbps transfer speeds, Cat 6 cable is necessary to transfer data over 1 Gbps. Cat 6 cables are usually more expensive than Cat 5/5e cables, but re-running new Ethernet lines can be time-consuming and costly. Therefore, it is typically worth the extra expense to future-proof a network with faster Ethernet cables. NOTE: Most Ethernet cables have the type of standard printed on the outer jacket. Updated January 9, 2021 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cat_6 Copy

Catalina

Catalina Catalina is the sixteenth version of Apple's macOS operating system and is also known as "macOS 10.15." It follows macOS Mojave (version 10.14) and was released on October 7, 2019. While Catalina includes several new features, it is primarily a performance update. Notably, Catalina is the first version of macOS to drop 32-bit support. By removing support for 32-bit applications, Apple trimmed a significant amount of "legacy" code from the OS. The result is a lighter-weight operating system optimized for 64-bit applications. While most modern apps are 64-bit, older 32-bit apps will not run in macOS 10.15. Catalina is also the first version of macOS that allows an iPad to serve as a secondary display. This feature, called "Sidecar," works with both a wired and wireless connection between a Mac and an iPad. It also introduces "Project Catalyst," which makes it possible for iOS and iPadOS apps to run on macOS. Most of Catalina's other new features are related to the bundled apps. For example, iTunes is replaced by three new apps: Music, Podcast, and TV. Mail adds message blocking and built-in unsubscribing. The Reminders app provides a new way to organize and manage reminders. Catalina also includes Screen Time, a feature introduced in iOS 12. It allows users to track how much time they spend on their computers, including how much they use individual apps. Updated May 13, 2021 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/catalina Copy

Cc

Cc Stands for "Carbon Copy." Cc is one of the standard email address fields. It is meant for secondary recipients of a message, while the To field is for its primary recipients. All email addresses in a message's Cc field receive a copy of the message, and will also receive any replies sent using the Reply All command. The term comes from the historic use of carbon paper to create copies of written documents and forms. Standard email courtesy reserves the Cc field for secondary recipients of an email message who benefit from being informed of the message's contents but whose input is not necessary. The To field, on the other hand, is for the primary participants in the exchange. For example, two coworkers discussing how to split up tasks in a project would exchange emails with each other's address in the To field; adding their manager's email address to the Cc field will keep them in the loop. In effect, the Cc field is an 'FYI' field. An email message with a recipient in the Cc field Every recipient of an email can see the addresses in both the To and Cc fields. The Blind Carbon Copy (Bcc) address field is for situations where a sender wants to hide a recipient's email address from other recipients. The Bcc field can keep a single recipient secret or prevent recipients of a mass email from knowing everyone else's email address. Addresses in the Bcc field will also not receive replies if another recipient sends a Reply All message. Updated December 19, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cc Copy

CCD

CCD Stands for "Charged Coupled Device." A CCD is a type of image sensor used to capture still and moving imagery in digital cameras and scientific instruments. A CCD sensor is a flat integrated circuit that contains an array of light-sensitive elements, called pixels, that capture incoming light and turn it into electrical signals. Other components in the device use these signals to construct a digital recreation of the original image. The quality of the image produced by a CCD depends on its resolution — the number of physical pixels present on the sensor. A sensor's resolution is measured in Megapixels (the total number of pixels in millions). For example, a 16 Megapixel sensor produces an image with twice as many total pixels as an 8 Megapixel sensor, resulting in a more detailed image. A physically-larger sensor can either pack in more pixels than a smaller one, or include larger pixels that are more sensitive to light. CCD sensors can also detect light outside the visible spectrum, enabling infrared photography and night-vision video recording. Since CCDs only capture the amount of light that hits the sensor, not the color of that light, an unfiltered sensor only produces a monochrome image. CCDs can use red, green, and blue (RGB) filters to capture colored light separately before combining the data into a full-color image. Some devices even include three separate CCDs, one each for red, blue, and green, to capture full-color image data in less time. While many early digital cameras used CCDs to capture images, other types of image sensors came along that were faster and less prone to overexposure. Eventually, most consumer- and professional-level digital cameras switched to CMOS image sensors. However, CCDs produce higher-quality images when overexposure is not a concern, so they're still used in scientific and medical instruments. They're even used in the harsh environment of space, taking photos of far-off galaxies from orbiting satellite telescopes. Updated December 27, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/ccd Copy

CD

CD Stands for "Compact Disc." A CD is a type of optical media for storing digital audio and data. CDs are circular discs, 120 mm (4.7 in) in diameter and 1.2 mm (0.047 in) thick. The underside of a CD consists of protective plastic over a reflective layer containing digital data, encoded as a series of pits and lands read by a laser as the disc spins in an optical drive. A standard CD can store 700 MB of data or up to 80 minutes of digital audio. CDs were first introduced in 1982 by Sony and Philips as a new music format. Unlike analog mediums like vinyl records and audio cassettes, you can listen to a CD an unlimited number of times without any loss of quality due to wear. CDs also separate audio into distinct audio tracks that you can jump directly to or skip over. All audio CDs use the same audio encoding format, known as the Red Book specification — two-channel (stereo) 16-bit PCM audio sampled at 44.1 kHz. Later in the 1980s, the CD was adapted to store computer data on CD-ROM discs. Since a single CD-ROM disc could contain as much data as several hundred floppy disks, they were an ideal format for distributing multimedia software and games. Recordable (CD-R) and rewritable (CD-RW) discs eventually allowed home computer users to burn their own CDs to share files, make custom music mixes, and back up their computers. NOTE: Later optical disc formats like DVD and Blu-Ray use the same dimensions as CDs but with much smaller pits and lands that store data more densely. This allows optical drives designed for DVDs and Blu-Ray discs to read and play CDs. Updated April 18, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cd Copy

CD-R

CD-R Stands for "Compact Disc-Recordable." CD-R is an optical media storage medium that can hold up to 700 MB of data. The discs are used for backing up data, sharing multimedia, and general data storage. Unlike traditional CDs that are factory-pressed with pre-recorded data, CD-Rs allow users to write data onto them once, making them a convenient and cost-effective archival solution. A CD-R disc is coated with a thin layer of dye and a reflective layer. When data is written, or "burned," onto a CD-R, a laser beam heats the dye, creating permanent physical changes that form pits (non-reflective) and lands (reflective) on the disc's surface. The pits and lands represent binary zeros and ones, which an optical drive can read as digital data. Top and bottom of a CD-R disc One key advantage of CD-Rs is their compatibility with a wide range of devices, including CD-ROM drives, CD players, and standalone CD burners. You can use CD-Rs to create music CDs, software installation discs, sharable photo albums, and data backups. Once data is written onto a CD-R, it cannot be erased or overwritten. Additionally, the quality of CD-Rs may degrade over time due to light exposure, heat, and humidity, potentially leading to data loss or corruption. Today, most PCs do not have optical drives, and CD-Rs are much less common than in the early 2000s. Newer data storage mediums such as flash drives and external hard drives read and write data faster and have much higher capacity. Updated June 7, 2024 by Nils-Henrik G. Reviewed by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cdr Copy

CD-ROM

CD-ROM Stands for "Compact Disc Read-Only Memory." CD-ROM is a read-only optical media format that uses CDs to store data. A computer with an optical drive can read, but not write, data on a CD-ROM. A single disc can store up to 700 MB of data. Some CD-ROM discs, known as "Enhanced CDs," store a combination of audio tracks and a data track. CD-ROM discs were often used to distribute software and video games in the 1990s and 2000s before eventually being replaced by higher-capacity DVDs. CD-ROM discs and audio CDs are physically identical, storing and retrieving data in the same method. Digital data is encoded and stored as a series of pits on a flat reflective layer on the bottom of the disc. The laser in the optical drive reads these pits, then decodes the data. The only difference between the two is how the data is formatted — multiple PCM audio tracks on an audio CD, or a single track containing data on a file system on a CD-ROM. An optical drive can spin a CD-ROM disc at a significantly higher speed than an audio CD player. A CD spinning at the standard rate for audio playback supports a data transfer rate of approximately 150 KB/s; at this speed, reading an entire CD-ROM full of data takes almost 80 minutes. CD-ROM drives are classified by how many times faster they can spin, with many drives capable of 40x (6,144 KB/s) or more. Updated October 25, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cdrom Copy

CD-RW

CD-RW Stands for "Compact Disc Re-Writable." CD-RW is the rewritable compact disc format. A rewritable CD can be written to, erased, and re-written hundreds of times. One disc can store up to 700 MB of data or 80 minutes of digital audio. Rewritable discs may not play correctly in all CD players, as the rewritable layer on the underside of the disc is not as reflective as the pressed layer on a CD-ROM. Writing to a CD-RW disc requires a compatible disc drive that supports rewriting optical media. Once data is written to a CD-RW disc, it is read-only and cannot be edited; in order to to make any changes to the files on a disc, it must be erased and re-written. This process makes the format a poor choice for storing files that need to be frequently modified. Instead, the rewritable discs are better suited for frequent data backups, although the format's small capacity compared to DVD±RW discs limits that use as well. An optical disc drive that can write discs has three lasers—a low-power laser that reads data, a medium-power laser that erases rewritable discs, and a high-power laser that burns data to a disc. A CD-RW drive burns a series of spots onto a reflective layer of a phase change metal alloy on the underside of the disc. At first, this metal alloy exists in a crystalline form that lets light through. A high-power burning laser heats the alloy past its melting point, which then turns opaque as it cools. These opaque spots encode digital data that the reading laser in the drive reads and decodes. When it's time to erase a disc, the drive uses the medium-powered erase laser to heat the alloy layer to its crystallization point. Updated November 4, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cdrw Copy

CDFS

CDFS Stands for "Compact Disc File System." CDFS is a file system used for storing data on CDs. It is a standard published by the International Organization for Standardization (ISO) and is also known as "ISO 9660." Discs that store data using the ISO 9660 standard can be recognized by multiple platforms, including Windows, Macintosh, and Linux systems. CDFS specifies several disc properties, including the volume attributes, file attributes, and file placement. It also specifies the overall data structure of a CD, such as the header size and the data storage area of the disc. While CDFS was originally designed for read-only single-session discs, an extension of the standard allows multiple-session writing to CD-R discs. This means multiple volumes may be stored on a single CD. The CDFS standard is useful for burning discs that will be shared between multiple computers. Because CDFS is not specific to a single operating system, a disc burned on a Macintosh using the compact disk file system can be read on a Windows or Linux-based computer. Disc images can also be saved using the CDFS standard, which may be used to burn ISO 9660 discs. These files are typically saved with an .ISO file extension. Updated January 20, 2011 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cdfs Copy

CDMA

CDMA Stands for "Code-Division Multiple Access." CDMA is a wireless transmission technology that allows multiple digital signals to travel over the same carrier channel. Qualcomm developed and patented CDMA as a commercial cellular networking method in the 1990s, and carriers first deployed networks using the technology in 1995. CDMA was one of two competing standards for 2G and 3G cellular data networks, along with GSM. A CDMA network assigns every user a code that encodes and decodes wireless signals sent to and from their device. Multiple users can communicate with the network's transmission towers using the entire width of the frequency spectrum. Each device decodes only the signals that use their personal code, with signals meant for other users appearing as noise that the receiver can safely discard. By not limiting each user's frequency range, CDMA provides more bandwidth when compared to the TDMA method used by GSM networks. CDMA also allows more simultaneous users to use the same frequency spectrum without negatively affecting network performance. Globally, CDMA networks were less common than GSM. CDMA was only widely used in the United States (primarily through Verizon) and parts of Asia. The two types of networks were incompatible, as they used different frequency ranges and thus required different radio hardware; however, during the later part of the 3G era it was common for smartphones to include radios for both. Both GSM and CDMA networks were gradually replaced during the 2010s by LTE networks. By the end of 2022, most carriers had retired their 2G and 3G networks entirely. Updated July 14, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cdma Copy

CDN

CDN Stands for "Content Delivery Network." A CDN is a group of servers distributed in different locations. Small CDNs may be located within a single country, while large CDNs are spread across data centers around the world. CDNs are used to provide content to users in different locations as quickly as possible. For example, a user in San Francisco may receive website content from a server in Los Angeles, while a user in England may receive the same content from a server in London. This is accomplished using data replication, which stores the same data on multiple servers. Whenever you access a website hosted on a CDN, the network will intelligently provide you with the content using the server closest to the your geographical location. By providing Internet-based content over a CDN, large businesses can avoid bottlenecks associated with serving data from a single location. It also helps limit the impact of security breaches, such as denial of service attacks. If hardware fails on one server, the CDN can quickly reroute traffic to the next best server, limiting or even eliminating downtime. While CDNs are often used to host websites, they are commonly used to provide other types of downloadable data as well. Examples include software programs, images, videos, and streaming media. Cloud computing services are often provided over content delivery networks as well. Since CDNs automatically choose the best server for each user, there is no need to manually choose the most efficient location, like some FTP download services require. NOTE: While CDNs are often accessed via standard URLs, many CDNs include the letters "cdn" in their web address. Updated September 13, 2013 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cdn Copy

Cell

Cell Spreadsheets are made up of rows and columns, which form a table or grid. A cell is a specific location within a spreadsheet and is defined by the intersection of a row and column. Since most spreadsheets use numbers to define rows and letters to define columns, cells are often referenced by a letter and number combination. For example, the cell A3 is located in the first column (A), in the third row of a spreadsheet. The cell B3 would be immediately to the right of A3 and the cell A4 would be directly below it. These examples are relative cell references, since they are based on the actual names of the cells. If a user changed the name of column A to "Income" and the name of row 3 to "Q3," the reference would be "IncomeQ3" instead of A3. However, you could also refer to the cell by the absolute cell reference, which is defined by $A$3. Many spreadsheet programs support absolute cell references, which are useful when creating formulas. Cells may contain several data types, including numbers, dates, times, currencies, percentages, text, and other types of data. Most spreadsheet programs allow you to format cells for different data types, which helps ensure uniform entries across multiple cells. For example, you could format the active cell (or currently selected cell) to US dollar currency. If you enter "123" in the cell, it may automatically change to "$123.00" when you press Tab or Enter or click outside the cell. If the active cell is formatted for a date, the text "1/2/3" may change to "01/02/2003." Cells may contain manually entered data or the results of calculations from other cells. For example, cell A20 may contain a formula that produces the result of the summation of cells A1-A15. Cell C5 may contain a formula that averages all the numbers in the B column. The data in spreadsheet cells that contain formulas are dynamically updated when the data in referenced cells are changed. Updated November 12, 2009 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cell Copy

Cell Reference

Cell Reference A cell reference, or cell address, is an alphanumeric value used to identify a specific cell in a spreadsheet. Each cell reference contains one or more letters followed by a number. The letter or letters identify the column and the number represents the row. In a standard spreadsheet, the first column is A, the second column is B, the third column is C, etc. These letters are typically displayed in the column headers at the top of the spreadsheet. If there are more than 26 columns, the 26th column is labeled Z, followed by AA for column 27, AB for column 28, AC for column 29, etc. Column 55 is labeled BA. Rows simply increment numerically from top to bottom starting with "1" for the first row. Examples of cell references are listed below: First column, seventh row: A7 Tenth column, twentieth row: J20 Sixty-first column, three hundred forty-second row: BI342 One thousand column, two thousandth row: ALL2000 Cell references are helpful in two ways: 1) They provide an easy way to locate a specific value within a spreadsheet, and 2) they are used in creating formulas. Locating Values If you are reviewing a spreadsheet with another user, you can simply use the column/row combination to reference a specific cell. You can also use the "Go To..." feature to jump to a specific cell. This is especially helpful when working with large spreadsheets that have hundreds or thousands of cells. Creating Formulas Most spreadsheet programs support formulas that can be used to calculate values based on the contents of other cells. For example, a cell may contain the function: =D8/E10 The above function will automatically populate the cell with the value stored in cell D8 divided by the value in E10. If G2 contains the function above, and D8 is 20 and E10 is 5, then G2 will display the value 4. A cell may also simply display the value of another cell. For instance, if G3 contained the function =D8, it would display 20 (the value stored in D8). Updated November 15, 2016 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cell_reference Copy

Certificate

Certificate An SSL certificate, or digital certificate, is a file installed on a secure web server that identifies a website. A digital certificate establishes the identity and authenticity of the company that runs a website so that visitors can trust that the website is secure and reliable. In order to verify that these sites are legitimate (that the owners are who they say they are), the companies and their websites are verified by a third-party certificate authority, such as IdenTrust or DigiCert. Once the certificate authority establishes the legitimacy of an organization and that they run the associated website, it will issue an SSL certificate. The cost for a certificate varies, depending on the level of support provided — some certificates are issued for free, but many cost around $60-$100 per year (or more). This digital certificate is installed on the web server and will be viewable when a user visits the website. Sites with a valid certificate load using HTTPS, and display a padlock icon next to the URL in the address bar. To view the certificate, click the padlock icon. Because digital certificates verify a company's current status, they do not last forever. Most SSL certificates expire after a year, with free certificates expiring after three months. If the certificate is not renewed in time, a site's visitors will see a warning in their web browser before the page loads, informing them that "This website's certificate has expired." While this does not necessarily mean the site is fraudulent, it does show that the site's administrators allowed their certificate to expire before renewing it. NOTE: Even though they are called SSL certificates by certificate authorities and website administrators, they now use the TLS security protocol. TLS replaced SSL in 1998, and SSL was eventually deprecated in 2015. Updated March 8, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/certificate Copy

CGI

CGI CGI has two different meanings: 1) Common Gateway Interface, and 2) Computer Generated Imagery. 1) Common Gateway Interface The Common Gateway Interface (CGI) is a set of rules for running scripts and programs on a web server. It specifies what information is communicated between the web server and clients' Web browsers and how the information is transmitted. Most Web servers include a cgi-bin directory in the root folder of each website on the server. Any scripts placed in this directory must follow the rules of the Common Gateway Interface. For example, scripts located in the cgi-bin directory may be given executable permissions, while files outside the directory may not be allowed to be executed. A CGI script may also request CGI environment variables, such as SERVER_PROTOCOL and REMOTE_HOST, which may be used as input variables for the script. Since CGI is a standard interface, it can be used on multiple types of hardware platforms and is supported by several types Web server software, such as Apache and Windows Server. CGI scripts and programs can also be written in several different languages, such as C++, Java, and Perl. While many websites continue to use CGI for running programs and scripts, developers now often include scripts directly within Web pages. These scripts, which are written in languages such as PHP and ASP, are processed on the server before the page is loaded, and the resulting data is sent to the user's browser. 2) Computer Generated Imagery In the computer graphics world, CGI typically refers to Computer Generated Imagery. This type of CGI refers to 3D graphics used in film, TV, and other types of visual media. Most modern action films include at least some CGI for special effects, while other movies, such as Pixar animated films, are built completely from computer-generated graphics. Updated June 24, 2010 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cgi Copy

Character

Character A character is any letter, number, space, punctuation mark, or symbol typed or entered on a computer. Some invisible characters are not represented on screen but are still present to modify or format text, like a tab or carriage return. When using the ASCII character set, a single character takes up one byte of storage space. For example, the phrase "Good afternoon!" is 15 characters and would take up 15 bytes of storage. Characters on a computer, like all other data, are stored as binary data. The particular sequence of bits that make up a single character needs to be defined by a character encoding method. The two most common encoding methods are ASCII and Unicode. ASCII stores a character as a single byte, supporting 128 different letters, numbers, punctuation, and symbols in the Latin alphabet. Unicode allows a single character to be defined by one to four bytes apiece—one byte for the Latin alphabet, numbers, and punctuation; two bytes for other alphabets like Greek, Cyrillic, and Hebrew; three bytes for Chinese, Japanese, and Korean characters; and four bytes for mathematical symbols and emoji. In addition to the vast array of letters, numbers, and symbols across the different alphabets, character encoding sets include some special characters that modify the text around them. The ASCII set includes control characters like the null character, which is used as a string terminator, a carriage return to start a new line, and a tab to insert a tab stop. Unicode specifies more groups of special characters, like word joiners and separators. These control where line breaks are allowed within and between words. NOTE: Most operating systems include a character map application or menu that you can use to insert special characters and/or emoji. Updated October 18, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/character Copy

Character Encoding

Character Encoding While we view text documents as lines of text, computers actually see them as binary data, or a series of ones and zeros. Therefore, the characters within a text document must be represented by numeric codes. In order to accomplish this, the text is saved using one of several types of character encoding. The most popular types of character encoding are ASCII and Unicode. While ASCII is still supported by nearly all text editors, Unicode is more commonly used because it supports a larger character set. Unicode is often defined as UTF-8, UTF-16, or UTF-32, which refer to different Unicode standards. UTF stands for "Unicode Transformation Format" and the number indicates the number of bits used to represent each character. From the early days of computing, characters have been represented by at least one byte (8 bits), which is why the different Unicode standards save characters in multiples of 8 bits. While ASCII and Unicode are the most common types of character encoding, other encoding standards may also be used to encode text files. For example, several types of language-specific character encoding standards exist, such as Western, Latin-US, Japanese, Korean, and Chinese. While Western languages use similar characters, Eastern languages require a completely different character set. Therefore, a Latin encoding would not support the symbols needed to represent a text string in Chinese. Fortunately, modern standards such as UTF-16 support a large enough character set to represent both Western and Eastern letters and symbols. Updated September 24, 2010 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/characterencoding Copy

ChatGPT

ChatGPT ChatGPT is an artificial intelligence chatbot developed by OpenAI that provides conversational responses to text prompts. It can answer questions, summarize articles, and provide creative prompts. While the chatbot can formulate humanlike responses, its algorithm is not error-proof and may produce inaccurate statements. The ChatGPT language model analyzes large data sets across thousands of topics. Examples of input include news articles, fiction and non-fiction books, social media posts, chat logs, and text from various websites. The model uses machine learning to process the data and find patterns and relationships between words. Once it identifies patterns, it uses that data to create inferences and generate new text — similar to how a mobile device's autocomplete feature suggests words as you type. After some fine-tuning by its developers, the model is able to generate long, natural-language responses to text prompts. Even though ChatGPT is more capable than older chatbots, it has its limitations. Any flaws in its data set, such as biased language or perspectives, can carry over into its responses. It also lacks the intuition, emotion, and contextual awareness of interpersonal conversation. Therefore, ChatGPT may not provide relevant or natural-sounding output in some instances. NOTE: A chat bot like ChatGPT can "hallucinate" content — generating text that looks convincing on the surface but, upon closer inspection, is factually incorrect or contextually irrelevant. Because ChatGPT aggregates information and does not provide references for its sources, it may be difficult to determine how much of its output is factually sound. Updated February 21, 2023 by Brian P. Reviewed by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/chatgpt Copy

Checksum

Checksum A checksum is a value used to verify the integrity of a file or a data transfer. In other words, it is a sum that checks the validity of data. Checksums are typically used to compare two sets of data to make sure they are the same. Some common applications include verifying a disk image or checking the integrity of a downloaded file. If the checksums don't match those of the original files, the data may have been altered or corrupted. A checksum can be computed in many different ways, using different algorithms. For example, a basic checksum may simply be the number of bytes in a file. However, this type of checksum is not very reliable since two or more bytes could be switched around, causing the data to be different, though the checksum would be the same. Therefore, more advanced checksum algorithms are typically used to verify data. These include cyclic redundancy check (CRC) algorithms and cryptographic hash functions. It is rare that you will need to use a checksum to verify data, since many programs perform this type of data verification automatically. However, some file archives or disk images may include a checksum that you can use to check the data's integrity. While it is not always necessary to verify data, it can be a useful means for checking large amounts of data at once. For example, after burning a disc, it is much easier to verify that the checksums of the original data and the disc match, rather than checking every folder and file on the disc. Both Mac and Windows include free programs that can be used to generate and verify checksums. Mac users can use the built-in Apple Disk Utility and Windows users can use the File Checksum Integrity Verifier (FCIV). Updated April 14, 2009 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/checksum Copy

Chicago

Chicago

Chip

Chip Technically speaking, a computer chip is a piece of silicon with an electronic circuit embedded in it. However, the word "chip" is often used as a slang term that refers to various components inside a computer. It typically describes an integrated circuit, or IC, such as a central processor or a graphics chip, but may also refer to other components such as a memory module. While "chip" is a somewhat ambiguous term, it should not be confused with the term "card." For example, a laptop might have a graphics chip embedded in the motherboard, while a desktop computer may contain a graphics card connected to a PCI or AGP slot. A graphics card may contain a chip, but the chip cannot contain a card. Similarly, a CPU may contain a chip (the processor), but it may also contain several other components. Therefore, the term "chip" can be used to refer to specific components, but should not be used describe multiple components that are grouped together. Updated June 25, 2008 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/chip Copy

Chiplet

Chiplet A chiplet is a small, self-contained block of integrated circuits that performs a specific function. Chip designers combine multiple chiplets with different uses into a single chip package. This type of chip package is similar to a System-on-a-Chip (SoC) processor, which combines several distinct components into a single chip. However, an SoC is manufactured as one piece, while chiplets are manufactured separately and combined later. Monolithic SoC designs combine every element into a single piece of silicon — the CPU, GPU, memory, I/O controllers, and other components. In a chiplet design, each chiplet is designed and manufactured independently, then combined into a chip package in a later step. High-speed interconnects join each chiplet in a chip package to allow data to flow between them as if they were part of a single chip. The AMD EPYC series of chips is designed using chiplets Chiplet-based designs provide several important benefits over normal SoC designs: Modularity — Chip designers can create chiplets for specific functions and combine them as necessary in a chip package. Specific chiplets within a design can receive updates without the entire chip receiving a redesign. Chip designers can even integrate chiplets from other manufacturers into their designs. Improved Yields — The smaller individual chiplets are easier to manufacture at scale than large, complex SoC chips. A single defect in an SoC may cause the entire chip to be unusable, but a manufacturer can test each individual chiplet to confirm it works before adding it to a chip package. Multiple Processes — Each chiplet within a chip package can be manufactured using the most suitable process for that chiplet. Components like CPU and GPU cores may use an advanced fabrication process that maximizes performance, while other components whose performance is not as critical can use an older, less expensive process. Improved Performance and Efficiency — Chip designers can optimize a chip package for specific tasks by changing the chiplets it uses. For example, a chip package optimized for graphics performance would include more high-power GPU cores than another chip of the same family designed for power efficiency, even though the other chiplets in the package would be identical. NOTE: As of 2023, most major processor manufacturers have started using chiplets in some of their processor designs, including Intel, AMD, and Apple. Updated November 7, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/chiplet Copy

Chipset

Chipset A chipset is a group of integrated circuits that work together. It may refer to the design of a single component or may describe the relationship of multiple components within a computer system. For example, the chipset of video card describes the design of the card, while a motherboard chipset describes its layout and the different components it supports. Diagrams are often used to illustrate chipset designs. For example, a diagram of a video card chipset may contain the GPU, video RAM, and the PCI bus. It may also include lines and arrows that represent the circuitry between the components. Together, the components and circuitry make up the overall design of the chipset, and may also be called the architecture of the video card. A motherboard chipset diagram may include components such as the CPU, RAM, video card, and I/O ports. A detailed diagram may also include lesser-known components, such as the northbridge, southbridge and frontside bus. Regardless of level of detail, all motherboard chipset diagrams include lines and arrows that visually describe the way data flows between the different components. Most internal computer components are designed for a specific chipset. Therefore, if you decide to upgrade any internal hardware, it is important to know what type of chipset your computer uses. In many cases, a computer's chipset is synonymous with the chipset of the motherboard. Once you find out what chipset your motherboard uses, you can determine what components are compatible with your machine. Updated July 31, 2012 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/chipset Copy

Chromebook

Chromebook A Chromebook is a laptop that runs Google's Chrome OS operating system. While Google sells its own Chromebook model, the Chromebook Pixel, many other manufacturers offer Chromebooks as well. Examples include Dell, HP, Toshiba, Samsung, ASUS, and Acer. Chromebooks are designed to be inexpensive and highly portable. They are considered thin clients since they have minimal internal storage. Unlike traditional laptops, Chromebooks are designed to run cloud-based applications and store data online. While the Chrome OS and some applications can run offline, Chromebooks work best when used with an Internet connection. The Chrome OS includes several Google apps, such as the Chrome web browser, Gmail, Google+, and YouTube applications. It also runs the Google Drive office suite and related apps such as Google Docs, Google Drawings, and Google Forms. Third party applications can be downloaded from the Chrome Web Store. Some Android apps can also run on Chrome OS via Google's App Runtime for Chrome (ARC). Since Chromebooks do not run Windows or OS X, they do not natively support many traditional applications, such as Microsoft Office. However, you can run online versions of Word, Excel, and other common applications from the Chrome OS or through the Chrome web browser. These applications run on a remote server, but look and function like traditional desktop applications. Chromebooks also support remote access software, which allows you operate Windows or OS X computers from a Chromebook. Updated April 7, 2015 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/chromebook Copy

CIFS

CIFS Stands for "Common Internet File System." CIFS is a standard file system designed for sharing files over the Internet. It is part of the SMB protocol, which allows multiple types of computers to share data and peripherals over a network. CIFS enables users to access files remotely from multiple platforms, including Windows, Mac, Linux, and others. Each operating system has its own file system, which defines how files and folders are organized. For example, most Windows computers use NTFS, while Macs user HFS. Proprietary file systems are fine when accessing files locally (from the computer itself), but it can cause compatibility issues when users try to access files from a remote system. If the remote device does not recognize the file system of the computer, it won't be able read the files. CIFS solves this problem by serving as a universal file system that is supported by multiple platforms. The Common Internet File System provides a standard set of commands that computers can use to access a remote system and read and write files remotely. It supports both anonymous file transfers and authenticated access, which can be used to prevent unauthorized access to certain folders and files. CIFS also includes file locking, which prevents multiple users from editing the same file at the same time. Updated December 19, 2012 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cifs Copy

Circuit

Circuit In electronics, a circuit is a closed path that allows electricity to flow from one point to another. It may include various electrical components, such as transistors, resistors, and capacitors, but the flow is unimpeded by a gap or break in the circuit. A flashlight is an example of a basic circuit. When the switch is off, the circuit is not closed, meaning electrical current will not flow from the batteries to the flashlight's bulb. When you move the switch to the on position, a piece of metal in the flashlight physically closes the gap in the circuit. Electricity from the batteries then flows to the bulb making it light up. In computing, the term "circuit" is used more liberally and may be used to reference a circuit board or an integrated circuit. The internal workings of computers and other electronic devices are comprised of these components, which may each contain hundreds or thousands of individual circuits. The large number of circuits inside computers allow them to route data to different locations and perform complex calculations. For example, a chip may route graphics operations to the GPU and other operations to the CPU. These processors contain logic gates that can rapidly open and close circuits. Modern processors have so many circuits and transistors, they can perform billions of instructions every second. Updated April 22, 2016 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/circuit Copy

CISC

CISC Stands for "Complex Instruction Set Computing," and pronounced "sisk." CISC is a type of processor design that includes a large set of computer instructions in its built-in instruction set. CISC instructions can vary in length, from simple tasks to multi-step operations, with longer tasks taking several clock cycles. CISC is one of two major design philosophies in instruction set design, along with Reduced Instruction Set Computing (RISC). The x86 processor architecture, which includes processors made by Intel and AMD, is the most widely-used type of CISC processor. A single instruction in a CISC instruction set may perform multiple operations — for example, a single instruction may tell the processor to load values from two memory banks, multiply them, then store the result. Integrating complex instructions directly into the processor's instruction set requires a software compiler to create fewer lines of assembly code, which in turn require less memory to store instructions. CISC vs RISC CISC and RISC are two different ideas of instruction set design. Each has its own advantages and drawbacks when compared to the other. CISC instruction sets contain more instructions that can handle more complicated tasks over several clock cycles, while RISC instruction sets include fewer instructions that each take a single clock cycle. When several RISC instructions are chained together to complete the same task as a single CISC instruction, the number of clock cycles required is often the same. CISC processors also require more transistors to store the larger instruction sets than RISC processors. RISC processors can use those transistors for memory storage instead, or use fewer transistors for a less-complex chip design — which can be smaller, require less power, and produce less heat. Updated December 8, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cisc Copy

Class

Class A class is used in object-oriented programming to describe one or more objects. It serves as a template for creating, or instantiating, specific objects within a program. While each object is created from a single class, one class can be used to instantiate multiple objects. Several programming languages support classes, including Java, C++, Objective C, and PHP 5 and later. While the syntax of a class definition varies between programming languages, classes serve the same purpose in each language. All classes may contain variable definitions and methods, or subroutines that can be run by the corresponding object. Below is an example of a basic Java class definition: class Sample {    public static void main(String[] args)    {       String sampleText = "Hello world!";       System.out.println(sampleText);    } } The above class, named Sample, includes a single method named main. Within main, the variable sampleText is defined as "Hello world!" The main method invokes the System class from Java's built-in core library, which contains the out.println method. This method is used to print the sample text to the text output window. Classes are a fundamental part of object-oriented programming. They allow variables and methods to be isolated to specific objects instead of being accessible by all parts of the program. This encapsulation of data protects each class from changes in other parts of the program. By using classes, developers can create structured programs with source code that can be easily modified. NOTE: While classes are foundational in object-oriented programming, they serve as blueprints, rather than the building blocks of each program. This is because classes must be instantiated as objects in order to be used within a program. Constructors are typically used to create objects from classes, while destructors are used to free up resources used by objects that are no longer needed. Updated April 18, 2011 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/class Copy

Clean Install

Clean Install A clean install is an operating system (OS) installation that overwrites all other content on the hard disk. Unlike a typical OS upgrade, a clean install removes the current operating system and user files during the installation process. When a clean install finishes, the hard disk only contains the new operating system, similar to a computer that is used for the first time. In most cases, a clean install is not necessary when upgrading your operating system. It is much easier and safer to perform a standard "upgrade and install," which simply upgrades the necessary files and leaves the user files in place. However, sometimes an OS upgrade is not possible because important files have become lost or corrupted. In this case, a clean install may be the only option. Some users may also prefer to perform a clean install so that no lingering problems from the previous OS will affect the newly installed operating system. Additionally, a clean install may be appropriate when installing an OS on a new hard drive or when transferring ownership of a computer to another person. Both Windows and Mac OS X allow you to perform a clean install when upgrading your operating system. The installer will give you the choice between a standard upgrade (typically the default option) and a clean installation near the beginning of the installation process. Windows 7 also lets you format and partition your installation disk if you select a clean install. In Mac OS X, you can use the Disk Utility program to format or partition your drive before you perform the clean install. NOTE: Since a clean install wipes out all data on the primary hard disk, it is crucial to back up your data before performing the installation. While it is wise to make sure you have a recent backup of your data before any OS upgrade, it is extremely important when performing a clean install. Backing up your data to an external hard drive or another computer are both good options. It is also smart to check your backup and make sure it contains all the files you need so you do not accidentally lose any files. Updated January 25, 2012 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/clean_install Copy

Cleanroom

Cleanroom A cleanroom is a controlled indoor space that maintains extremely low levels of airborne particles and contaminants. These rooms are essential for industries that produce highly sensitive equipment, such as microprocessors, pharmaceuticals, and medical devices, where even microscopic dust particles can compromise product quality and safety. To minimize contamination, cleanrooms utilize high-efficiency particulate air (HEPA) or ultra-low penetration air (ULPA) filters that continually circulate and purify the air. They often employ sophisticated airflow designs, which direct purified air in a consistent, unidirectional stream, preventing particles from settling on surfaces or products. Cleanrooms also regulate temperature, humidity, and air pressure to maintain optimal conditions and reduce the risk of interference with production processes. Monitoring systems continuously assess particle levels, temperature, and other parameters to ensure the room remains within the required limits. Cleanroom workers holding a flexible circuit Personnel in cleanrooms must wear specialized protective garments, often called "bunny suits," which cover them entirely to prevent contaminants from entering the environment. These suits resemble space attire but are lightweight and designed to allow for ease of movement in the controlled setting. Cleanroom Classifications Cleanrooms are classified according to international standards, such as the ISO 14644-1 standard, which defines the maximum permissible particle count for various particle sizes. For example, an ISO Class 6 cleanroom (Federal Standard Class 1000) permits up to 1,000 particles larger than 0.5 microns per cubic foot of air. An ISO Class 5 cleanroom (Federal Standard Class Class 100) allows no more than 100 such particles. Most CPU fabrication requires Class 6 or higher. NOTE: Cleanrooms may also be called "clean rooms." Updated October 28, 2024 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cleanroom Copy

Client

Client Businesses have clients and servers have clients. In both instances, there exists a one-to-many relationship. Just like a business may have several clients, a server can communicate with multiple clients. In computer networking, this is called the client-server model. A client is any device that communicates with a server. It may be a desktop computer, laptop, smartphone, or any other network-compatible device. In a home network, "smart" devices, such as Wi-Fi-enabled thermostats, lights, and appliances, are considered clients. In an office network, systems that access files from network-attached storage are clients of the file server. Most networks allow client-to-client communication, though the data flows through a central point, such as a router or switch. On a larger scale, whenever you access a website, your device is the client, and the web server hosting the website is the server. From a software perspective, your web browser is the client software and the program that responds to requests on the web server (Apache, IIS, etc.), is the server software. Similarly, when you check your email, you connect to a mail server. Your device is a client of the mail server, and your email program or webmail interface is the client software. Updated February 6, 2021 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/client Copy

Client-Server Model

Client-Server Model The client-server model describes how a server provides resources and services to one or more clients. Examples of servers include web servers, mail servers, and file servers. Each of these servers provide resources to client devices, such as desktop computers, laptops, tablets, and smartphones. Most servers have a one-to-many relationship with clients, meaning a single server can provide resources to multiple clients at one time. When a client requests a connection to a server, the server can either accept or reject the connection. If the connection is accepted, the server establishes and maintains a connection with the client over a specific protocol. For example, an email client may request an SMTP connection to a mail server in order to send a message. The SMTP application on the mail server will then request authentication from the client, such as the email address and password. If these credentials match an account on the mail server, the server will send the email to the intended recipient. Online multiplayer gaming also uses the client-server model. One example is Blizzard's Battle.net service, which hosts online games for World of Warcraft, StarCraft, Overwatch, and others. When players open a Blizzard application, the game client automatically connects to a Battle.net server. Once players log in to Battle.net, they can see who else is online, chat with other players, and play matches with or against other gamers. While Internet servers typically provide connections to multiple clients at a time, each physical machine can only handle so much traffic. Therefore, popular online services distribute clients across multiple physical servers, using a technique called distributed computing. In most cases, it does not matter which specific machine users are connected to, since the servers all provide the same service. NOTE: The client-server model may be contrasted to the P2P model, in which clients connect directly to each other. In a P2P connection, there is no central server required, since each machine acts as both a client and a server. Updated June 17, 2016 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/client-server_model Copy

Clip Art

Clip Art Clip art is a collection of pictures or images that can be imported into a document or another program. The images may be either raster graphics or vector graphics. Clip art galleries many contain anywhere from a few images to hundreds of thousands of images. Clip art is typically organized into categories, such as people, objects, nature, etc., which is especially helpful when browsing through thousands of images. Most clip art images also have keywords associated with them. For example, a picture of a female teacher in a classroom may have the keywords "school," "teacher," "woman," "classroom," and "students" associated with it. Most clip art programs allow you to search for images based on these keywords. When you find a clip art image you want to use, you can copy it to your computer's clipboard and paste it into another program, such as Photoshop or Microsoft Word. You may also be able to export the image to the Desktop or another folder on your hard disk. Most clip art is royalty free, meaning you can use the images without paying royalties to the creators of the images. So if you buy a clip art package with 50,000 images for $50.00, you are only paying 1/10 of one cent for each image. That's a pretty good deal. Updated in 2006 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/clipart Copy

Clipboard

Clipboard The clipboard is a special location in a computer's memory that temporarily stores copied data. It can hold any data type, including text, images, video, and audio. It can even store entire files and folders. Data can be added to the clipboard using the Copy or Cut commands and placed in a new location using the Paste command. The clipboard can (in most cases) store one piece of data at a time. It does not clear its contents when you paste them, so you can paste the same piece of data multiple times in different locations without copying it again. For example, you can copy an email address from a contact card and paste it into a web form or a text document without copying it multiple times. Copying or cutting replaces the existing clipboard contents with new data. The clipboard's previous contents cannot be recovered once replaced, so if you cut something important from a document, paste it somewhere before copying or cutting something else. Since the clipboard stores its contents in the system RAM, it is also cleared when a computer is shut down or rebooted. In recent years, popular operating systems have improved the built-in clipboard to make it more powerful and convenient. For example, Windows 10 (and later versions) has an optional Clipboard History feature that lets you store multiple items in the clipboard and choose which item to paste using a separate keyboard shortcut: Windows Key + V. Third-party clipboard management utilities can add a similar feature to other operating systems. The Windows 10 Clipboard History feature The Universal Clipboard feature in macOS, iOS, and iPadOS allows you to copy data from one device and paste it on another. For example, you can copy an image from your iPhone and paste it into a document on your Mac, as long as you're signed into the same iCloud account on both devices and they are on the same local network. Updated July 5, 2023 by Brian P. Reviewed by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/clipboard Copy

CLOB

CLOB Stands for "Character Large Object." A CLOB is a data type used by various database management systems, including Oracle and DB2. It stores large amounts of character data, up to 4 GB in size. The CLOB data type is similar to a BLOB, but includes character encoding, which defines a character set and the way each character is represented. BLOB data, on the other hand, consists of unformatted binary data. Common data types used for storing character data include char, varchar, and text. Some database management systems also support additional text data types such as tinytext, mediumtext, and longtext. If the standard character data types are not large enough for a certain database field, the CLOB data type may be used. Since CLOB data may be very large, some database management systems do not store the text directly in the table. Instead, the CLOB field serves as an address, which references the location of the data. CLOBs provide a way to store unusually large amounts of text, such as an entire book or publication. However, some database programs cannot run certain text operations on CLOB fields, such SQL commands with the "LIKE" condition. Therefore, it is often better to use other character data types for smaller text values. Updated July 9, 2009 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/clob Copy

Clock Cycle

Clock Cycle A clock cycle, or simply a "cycle," is a single electronic pulse of a CPU. During each cycle, a CPU can perform a basic operation such as fetching an instruction, accessing memory, or writing data. Since only simple commands can be performed during each cycle, most CPU processes require multiple clock cycles. In physics, the frequency of a signal is determined by cycles per second, or "hertz." Similarly, the frequency of a processor is measured in clock cycles per second. Since modern processors can complete millions of clock cycles every second, processor speeds are often measured in megahertz or gigahertz. The frequency of a processor is also known as the processor's clock speed. While the clock speed is important in determining the processor's overall performance, it is not the only factor. Since processors have different instruction sets, they may differ in the number of cycles needed to complete each instruction, or CPI (cycles per instruction). Therefore, some processors can perform faster than others, even at slower clock speeds. Updated July 24, 2010 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/clockcycle Copy

Clock Speed

Clock Speed Clock speed measures how many processing cycles a processor can complete per second. It is typically measured in megahertz (millions of cycles per second) or gigahertz (billions of cycles per second) — for example, a processor with a clock speed of 3.0 GHz can perform 3 billion cycles per second. A processor's clock speed is one of its primary specifications and contributes to its total performance. A CPU's clock speed is determined by multiplying a base clock signal (provided by the motherboard) by an internal multiplier value on the processor itself. For example, if the base clock signal is 100 MHz and the processor multiplier is 30x, the processor runs at a clock speed of 3 GHz. Some high-end processors have an unlocked multiplier that can be changed in the BIOS or UEFI settings, allowing you to overclock the processor. A CPU may also have a turbo mode (called Turbo Boost on Intel CPUs and Precision Boost on AMD CPUs) that automatically increases clock speed when the processor is under high demand. However, this consumes more energy and thus produces more heat, so a processor can only engage this mode temporarily before returning to its base speed. Processor clock speed displayed in Windows System settings When all other variables are the same, a processor with a higher clock speed will outperform a slower one. However, other architectural factors can also affect processor performance, limiting how well clock speed can serve as a point of comparison. For example, some architectures may use optimized instruction sets to reduce how many cycles are needed to perform certain functions. Increasing the number of processor cores can also increase performance without increasing clock speed, allowing one processor to perform more simultaneous calculations. In many cases, a newer processor with a more optimized architecture will outperform an older processor running at a higher clock speed, so it is more helpful to consult performance benchmarks when comparing CPUs instead of relying on clock speed alone. Updated October 23, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/clock_speed Copy

Clone

Clone In computing, the word "clone" can mean several things. It may refer to a disk whose contents have been duplicated exactly from another disk in a process called "disk cloning." It may refer to software that mimics the functionality of a pricier mainstream alternative. It may also refer to IBM-compatible computers made by other companies in the 1980s and 90s. Disk Clones A disk clone is a disk whose contents were copied from another disk using a disk cloning utility. Cloning a drive involves more than just copying a disk's files; it duplicates the entire file system, including all partitions and metadata. Disk cloning is often used for creating backups, duplicating a configuration for deployment, and preserving the contents of a disk for digital forensics. Cloning a disk may also involve creating a disk image file. SuperDuper! is a disk cloning utility for macOS Disk cloning functionality is generally provided by third-party utilities. Cloning a disk requires that it not be in use, which means that you cannot clone a computer's boot disk while the operating system is running. Some disk cloning utilities, like Clonezilla, create a bootable flash drive that you can load instead of your operating system, leaving the boot drive available for cloning. Application Clones An application clone is a software application that reproduces the functionality of another, more popular application. Clone apps may be made for people who cannot afford the original application, run an operating system that the original application does not support, or just want a free and open-source alternative. For example, Inkscape is a popular open-source Adobe Illustrator clone, providing similar functionality for creating vector drawings and illustrations. IBM Clones In the 1980s and 1990s, "IBM clone" or "IBM-compatible" meant that a computer used the same architecture as the original IBM Personal Computer (PC), but was built by another manufacturer. After the IBM PC debuted in 1981, other companies like HP, Dell, and Compaq built computers using the same Intel CPUs as the PC. Marketed as "IBM-compatible," these clones could run the same software as the IBM PC (including the MS-DOS operating system). Due to the hardware and software compatibility between IBM PCs and third-party clones, the x86 architecture running MS-DOS (and later Microsoft Windows) became an industry standard. The entire ecosystem of PC clones would eventually be known as "PCs." The term is still synonymous with computers running Windows on Intel CPUs well after IBM has stopped making personal computers. NOTE: IBM's PC was not the only computing platform to be cloned. In the mid-1990s, Apple briefly licensed the Macintosh platform to third-party manufacturers through the "Macintosh Clone Program." However, this program was short-lived and only allowed clones between 1994 and 1997. Updated August 15, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/clone Copy

Cloud

Cloud The term "cloud" comes from early network diagrams, in which the image of a cloud was used to indicate a large network, such as a WAN. The cloud eventually became associated with the entire Internet, and the two terms are now used synonymously. The cloud may also be used to describe specific online services, which are collectively labeled "cloud computing." Examples of popular cloud-based services include web applications, SaaS, online backup, and other types of online storage. Traditional Internet services like web hosting, email, and online gaming may also be considered part of the cloud since they are hosted on Internet servers, rather than users' local computers. Even social networking websites such as Facebook and LinkedIn are technically cloud-based services, since they store your information online. While "the cloud" is simply a buzzword for most consumers, it plays an important role for businesses. By moving software services to the cloud, companies can share data more efficiently and centralize their network security. Additionally, cloud-based virtualization can help businesses reduce the number of computer systems and software licenses they need to buy. The end result and a more efficient and less costly way of running a business. Updated May 30, 2012 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cloud Copy

Cloud Computing

Cloud Computing Cloud computing refers to applications and services offered over the Internet. These services are offered from data centers all over the world, which collectively are referred to as the "cloud." This metaphor represents the intangible, yet universal nature of the Internet. The idea of the "cloud" simplifies the many network connections and computer systems involved in online services. In fact, many network diagrams use the image of a cloud to represent the Internet. This symbolizes the Internet's broad reach, while simplifying its complexity. Any user with an Internet connection can access the cloud and the services it provides. Since these services are often connected, users can share information between multiple systems and with other users. Examples of cloud computing include online backup services, social networking services, and personal data services such as Apple's MobileMe. Cloud computing also includes online applications, such as those offered through Microsoft Online Services. Hardware services, such as redundant servers, mirrored websites, and Internet-based clusters are also examples of cloud computing. Updated April 23, 2009 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cloud_computing Copy

Cloud Waste

Cloud Waste Cloud waste is unnecessary spending on cloud services. It refers to unused or underused services during one or more billing cycles, which results in "wasted" spending. Many types of cloud waste exist. Some examples include: Unused apps in Adobe Creative Cloud Unused Microsoft 365 subscriptions Underutilized server bandwidth Unnecessary cloud security features Underused cloud computing services Underused monthly mailing list email sends Cloud waste affects everyone from home users to enterprise businesses. For example, a student who purchases an annual Creative Cloud subscription but only uses it for six months may waste several hundred dollars a year. A company that purchases 10,000 Microsoft 365 licenses or "seats" but only uses 8,000 may waste thousands of dollars a month in unused subscription fees. In recent years, many companies have switched from desktop software to SaaS solutions to reduce costs. However, CTOs and other managers must monitor SaaS usage since unnecessary subscriptions can go overlooked for months or even years. Cloud computing platforms like Azure, AWS, and Google Cloud provide usage-based billing, which helps reduce cloud waste. Similar to an electrical meter, these services track each client's specific usage, such as compute time, API calls, bandwidth used, etc. Still, many cloud platforms have base monthly service fees and charge for add-ons that may go underutilized over time. Cloud-based services provide an efficient and cost-effective way for companies to manage IT solutions. However, it is essential for individuals and organizations to regularly review their cloud subscriptions to make sure they are not wasting money on unnecessary services. Updated June 23, 2022 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cloud_waste Copy

Cluster

Cluster In computing, a cluster may refer to two different things: 1) a group of sectors in a storage device, or 2) a group of connected computers. 1) A group of sectors A sector is the smallest unit that can be accessed on a storage device like an HDD or SSD. A cluster, or allocation unit, is a group of sectors that make up the smallest unit of disk allocation for a file within a file system. In other words, a file system's cluster size is the smallest amount of space a file can take up on a computer. A common sector size is 512 bytes. A common cluster size is 8 sectors. Therefore, many file systems have a minimum cluster size of 4 kibibytes (8 x 512 bytes). Most files require a large number of clusters, which means the file contents are spread across multiple clusters on the drive. Often the data can be written in contiguous blocks so that the file contents are stored in one physical location. However, when a hard drive begins to fill up, there may not be enough contiguous clusters available to save large files in a single area. Instead, they must be written in multiple locations on the disk. This is called fragmentation and can slow down the hard drive's read and write speeds. 2) A group of connected computers A cluster can also refer to a group of machines that work together that perform a similar function. Unlike grid computing, a computer cluster is controlled by a single software program that manages all the computers or "nodes" within the cluster. The nodes work together to complete a single task. This process is called "parallel computing" since the nodes perform operations in tandem. Computer clusters can range from two machines to hundreds of connected computers. Small clusters are often used to improve the performance of web and online gaming services by handling multiple incoming requests in parallel. A web farm, for example, is a type of cluster that provides low latency access to websites. Large clusters can be used to perform scientific calculations or to run a large number of complex algorithms. For example, a large cluster may be used to apply textures and lighting effects to 3D models in each frame of an animated movie. Updated April 22, 2015 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cluster Copy

CMOS

CMOS Stands for "Complementary Metal Oxide Semiconductor." It is a technology used to produce integrated circuits. CMOS circuits are found in several types of electronic components, including microprocessors, batteries, and digital camera image sensors. The "MOS" in CMOS refers to the transistors in a CMOS component, called MOSFETs (metal oxide semiconductor field-effect transistors). The "metal" part of the name is a bit misleading, as modern MOSFETs often use polysilicon instead of aluminum as the conductive material. Each MOSFET includes two terminals ("source" and "drain") and a gate, which is insulated from the body of the transistor. When enough voltage is applied between the gate and body, electrons can flow between the source and drain terminals. The "complimentary" part of CMOS refers to the two different types of semiconductors each transistor contains — N-type and P-type. N-type semiconductors have a greater concentration of electrons than holes, or places where an electron could exist. P-type semiconductors have a greater concentration of holes than electrons. These two semiconductors work together and may form logic gates based on how the circuit is designed. CMOS Advantages CMOS transistors are known for their efficient use of electrical power. They require no electrical current except when they are changing from one state to another. Additionally, the complimentary semiconductors work together to limit the output voltage. The result is a low-power design that gives off minimal heat. For this reason, CMOS transistors have replaced other previous designs (such as CCDs in camera sensors) and are used in most modern processors. NOTE: CMOS memory in a computer is a type of non-volatile RAM (NVRAM) that stores BIOS settings and date/time information. Updated May 25, 2017 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cmos Copy

CMP

CMP Stands for "Consent Management Platform." A CMP is a software application that helps website and app owners track whether their users consent to the gathering of their data. This personal data helps provide targeted advertising based on the user's demographic information and online activity. The use of a CMP that properly tracks and manages user consent is required to track user data from EU residents. Multiple vendors provide CMPs that help track user preferences, allowing businesses to choose the one that fits their needs. All CMPs must have a baseline set of tools. When you visit a site that collects data using a CMP, they must provide a user interface for requesting your consent — typically, a message box that appears when you first visit the site or open the app. These messages should help you understand what data is collected, who may access it, and what it will be used for. Many also allow you to customize what you consent to by sharing only certain types of data with certain third parties. A pop-up provided by a CMP that allows you to customize which third parties can access your data A CMP must include a database that keeps a record of who consents and who opts out of data tracking. They must also allow you to withdraw consent later if you wish. A CMP may also provide the actual tracking mechanism — typically cookies — and a connection to a third-party data processing service that analyzes collected user data. The use of a CMP is required by the Transparency Consent Framework (TCF). The TCF is an open standard framework that outlines when user consent is needed, how to ask for it, how to track it, and what a website or app owner may do with the personal data they collect. The TCF was developed to help websites and advertisers comply with the General Data Protection Regulation (GDPR) law in the EU. Updated August 25, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cmp Copy

CMS

CMS Stands for "Content Management System." A CMS is a software tool that allows you to create, edit, and publish content. While early CMS software was used to manage documents and local computer files, most CMS systems are now designed exclusively to manage content on the Web. The goal of a CMS is to provide an intuitive user interface for building and modifying webpage content. Each CMS also provides a web publishing tool that allows one or more users to publish updates live on the Web. The editing component is called the content management application (CMA), while the publishing tool is called the content delivery application (CDA). These two components are integrated together in a CMS to streamline the web development process. Content management systems are available as installable applications and web-based user interfaces. While CMS software programs, such as Adobe Contribute, were popular for a few years, they have largely been replaced by web-based CMSes. Most people prefer a web interface, since it simplifies the website updating process. Additionally, most web-based CMSes are updated automatically, ensuring all users have the latest tools to manage their content. Several web-based CMS tools are available. The following are some of the most popular ones: WordPress - free web software designed for creating template-based websites or blogs Blogger - Google's blogging tool designed specifically for maintaining a blog Joomla - a flexible web publishing tool that supports custom databases and extensions Drupal - an open source platform often used for developing community-based sites Weebly - a web-based platform for building simple personal and business websites Wix - a collection of web publishing tools for creating a highly customizable website Some CMS tools are free to use, while others require a monthly fee. Many CMSes provide free basic components, but charge for high-quality templates, web hosting, custom domain names, or other features. Before deciding on a CMS, it is a good idea to review multiple options so you can choose the one that best fits your website goals. Updated March 28, 2013 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cms Copy

CMYK

CMYK Stands for "Cyan Magenta Yellow Black," or "Cyan Magenta Yellow Key." CMYK is a color model used for printing color images. It separates colors into four channels — cyan, magenta, yellow, and black. These colors correspond to the four ink colors used in home and commercial printers. Graphics and documents must be converted from RGB into CMYK before printing, either by image editing software or automatically by the printer driver. Some colors may appear duller after conversion to CMYK due to differences between the two models. RGB color spaces typically have a larger color gamut, since computer monitors can display more colors than mixed inks. A color photograph split into cyan, magenta, yellow, and black channels Unlike RGB and most other color models, CMYK is a subtractive model. All four CMYK color sliders set to 0% creates white, since that value represents the lack of ink on a blank page. Increasing the value of each color slider results in darker colors as more ink is added, until each slider at 100% results in black. CMYK color uses black ink in addition to the three colored inks for several reasons. Black ink is cheaper than color ink, so it is more efficient to use it whenever possible. Black ink also produces a truer black than a combination of color inks due to impurities present in the colors. Creating black by mixing colors also requires that the print heads or plates for the three colors are perfectly aligned; otherwise, text, lines, and other details will blur. NOTE: The "K" in the abbreviation represents black ink, but it actually stands for "key." This term comes from the plates used in a commercial four-color printing process. The three color ink plates create the areas of color on the page, but the black ink plate is responsible for the contrast and fine details in the resulting image. As a result, the black ink plate is known as the "key plate." Updated April 20, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cmyk Copy

Coaxial Cable

Coaxial Cable Coaxial (or “coax”) cable is a common type of cable used for transmitting data over long distances. It can carry either an analog or digital signal. While coax cables have many applications, they are most commonly used to transmit cable TV and Internet signals. Coax cables that run underground are typically thicker and more heavily insulated than the cables that connect your cable box or cable modem to the wall outlet. However, they all transmit data via a thin copper line in the middle of the cable. This wire is surrounded by a layer of insulation comprised of non-conductive or “dielectric” material. The dielectric layer is covered with one or more metallic shields that provides additional protection from signal interference. Finally, a protective plastic outer layer surrounds the entire cable. The heavy duty design of coaxial cables is what allows them to carry data over long distances with minimum signal degradation. In many cases, coax cables laid by cable companies several decades ago are sufficient to provide HDTV and high-speed Internet access simultaneously. However, certain coax cables (such as RG-59 cables) are designed for low bandwidth applications, like connecting a VCR to a TV, and may not provide enough bandwidth to carry a full HDTV signal. Coax cables labeled as “RG-6” are a better choice for HDTV and cable Internet service. Updated December 27, 2013 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/coaxial_cable Copy

Codec

Codec Codec is short for "coder-decoder." It is an algorithm used to encode data, such as an audio or video clip. The encoded data must be decoded when played back. A media codec is not equivalent to media compression, since it is possible to encode a file without compressing it. However, most codecs do compress the original data, reducing the size of the original file. This is important for multimedia files, since they often have large file sizes. Compressed files take up less disk space and can be downloaded more quickly. Generally, a codec reduces the file size of a media file, but increases the processing power required to play the file back correctly. Lossless vs Lossy Codecs Some codecs are lossless, meaning they do not reduce the quality of the original media file. Examples of lossless audio codecs include the Free Lossless Audio Codec (FLAC), and the Apple Lossless Audio Codec (ALAC). Video codecs that support lossless compression include H.264 and QuickTime RLE. A lossless codec can often reduce the file size of a media file to about 50% without altering the quality. Other codecs are lossy, meaning the compression reduces the quality of the media. Examples of lossy audio codecs are Adaptive Differential Pulse Code Modulation (ADPCM) and MPEG-1 Layer 3 (MP3). Common lossy video codecs include MPEG-2 and HEVC. Most lossy codecs provide a variable compression setting, which allows you to select how much to compress the media. For example, if you apply heavy compression to an audio file, it may reduce the file size to 10%, but the audio may sound like it has been compressed. If you use a lower compression setting that reduces the file size to 30%, it may be closer to the original file. NOTE: Lossy codecs are commonly applied to streaming media so the data can be transferred more quickly over the Internet. Updated June 14, 2018 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/codec Copy

Cold Boot

Cold Boot To perform a cold boot (also called a "hard boot") means to start up a computer that is turned off. It is often used in contrast to a warm boot, which refers to restarting a computer once it has been turned on. A cold boot is typically performed by pressing the power button on the computer. Both a cold boot and warm boot clear the system RAM and perform the boot sequence from scratch. However, unlike a cold boot, a warm boot may not clear all system caches, which store temporary information. Additionally, a cold boot performs a "power on self test" (POST), which runs a series of system checks at the beginning of the boot sequence. While a warm boot and cold boot are similar, a cold boot performs a more complete reset of the system than a warm boot. Therefore, if you are troubleshooting your computer, you may be asked to turn off your computer completely and perform a cold boot. This makes sure all temporary data is wiped from your system, which may help eliminate issues affecting your computer. Updated February 19, 2013 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cold_boot Copy

Collision

Collision In computer science, a "collision" has two different meanings. One occurs when two or more sets of data are modified and produce the same resulting value. The other is specific to networking and happens when two devices transmit data at the same time. 1. Data Collision A data collision may take place when hashing data or when calculating a checksum. A hash function reduces data to a smaller value and is often used in compression and cryptography. While the hash operation may save disk space, it is possible that two different inputs may produce the same output. Multiple hash functions can be used to avoid duplicate values when a collision occurs. Similarly, checksums are not guaranteed to be unique since they are smaller than the original data. While the probability is often very low, two different data sets can theoretically produce the same checksum value. A well-designed algorithm should minimize this risk. 2. Network Collision A network collision occurs when two or more devices attempt to transmit data over a network at the same time. For example, if two computers on an Ethernet network send data at the same moment, the data will "collide" and not finish transmitting. This is why most networking protocols confirm that packets has been received before transmitting additional data. Switches and routers can reduce collisions by checking if a transmission line is idle or "in use" before transmitting data. A common method is CSMA/CD or "Carrier-sense multiple access with collision avoidance." While it is possible to reduce collisions, they cannot be completely avoided. For example, if two systems determine a line is idle and then transmit data at exactly the same time, a collision may occur. This can be resolved by retransmitting the data after a random delay. Updated December 20, 2018 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/collision Copy

Color Depth

Color Depth Color depth, also known as bit depth, refers to the number of bits used to store color information for each pixel in a digital image. Using more bits per pixel allows a greater range of possible colors. Color depth can be measured using the total number of bits used for a pixel (bits per pixel) or the number of bits for each RGB channel (bits per channel). Most digital images and computer monitors use 24-bit color, which supports 16.7 million possible colors. Images and monitors that use a low color depth are limited in the range of colors they can show. For example, a single bit of color depth only provides two possible values for a pixel, resulting in a black-and-white image, while 4 bits of depth allow for 16 possible color values. Higher color depth allows a wider range of color information, but requires more data to store images and more bandwidth to send the video signal to the monitor. An image in 8-bit and 24-bit color Common Color Depths Since 16 million colors are more than the human eye can distinguish, 24-bit color is considered good enough for general use. However, some formats and workflows use other color depths. 8-bit color saves each pixel using a single byte of data, displaying a maximum of 256 possible colors. Most 8-bit images use indexed color, which creates a palette of 256 colors out of a wider gamut. They also use dithering to blend colors together more smoothly. .GIF and low-color .PNG images use 8-bit color. 24-bit color is referred to as True Color. It uses 8 bits per RGB channel to display 16.7 million possible colors. Most computer monitors are limited to 24-bit color. Some image formats add an 8-bit alpha (transparency) channel to use 32 bits per pixel. Most digital images and HD videos use this depth. 30-bit color is referred to as Deep Color. It uses 10 bits per RGB channel to display more than 1 billion possible colors. This depth allows for higher contrast and increased luminance levels, which is important for high-end HDR monitors and UHD 4K televisions. Most 4K videos use this depth. High-end digital cameras can capture images at even greater color depths when taking RAW photos, providing photographers with extra image data for more-precise photo editing. Depending on the sensor, digital cameras can take RAW photos with 12, 14, or even 16 bits per channel (36 to 48 bits total). Updated February 14, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/color_depth Copy

Color Model

Color Model A color model is a way to represent colors mathematically using sets of numbers. A color model defines several measurable attributes of color (such as hue, saturation, and brightness) and represents each attribute as a number within a range. Most color models use sets of three values to define a color, while some use four. Each color model measures a different set of attributes and the relationship between those attributes. The most common color model for displaying digital images on a computer is the RGB model, which separates color into red, green, and blue light. The most common model for printing images, CMYK, instead represents colors as a mix of cyan, magenta, yellow, and black inks. Other models measure other properties of color like hue, luminance, saturation, or the deviation from a specified middle color. The same color represented numerically by 4 color models Software applications can convert color information from one model to another. For example, an image editing application that supports multiple color models allows a graphic designer to primarily use the HSL color model, which makes subtle color adjustments more intuitive. Meanwhile, the computer automatically converts it to the RGB model when it sends the image to the monitor. While color models define how colors are measured numerically, they do not necessarily represent the limited range of colors a device can display. In most cases, it isn't useful to specify a color that cannot be shown. Software and hardware makers split many color models, particularly RGB, into smaller color spaces that use a limited subset of colors. Updated April 5, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/color_model Copy

Color Profile

Color Profile A color profile (also known as an ICC profile) is a set of configuration data that tells a computer how to display colors on a given device. Each color profile contains data about the total range of colors available (known as a gamut), and how to map color values to other standard color spaces. It may also include the performance characteristics of a specific device, like its color temperature and gamma. A computer's color management software uses color profiles to keep colors consistent between devices. Monitors, digital cameras, scanners, and printers come with color profiles provided by their manufacturers. These profiles include specific information about how a device captures or displays colors. They are created by measuring the device using specific sample colors, calibrating its settings until the sample colors are accurate, then saving those calibration details to its profile. Color profiles adjust the colors in a photograph between the camera, working color space, display, and printer While many color profiles are specific to certain devices, there are standard profiles for common color spaces. Generic color profiles for color spaces like sRGB, Adobe RGB, and LAB provide a common working profile for creating and editing digital images. When necessary, color management software converts colors from generic profiles to device-specific ones and vice versa. Computers translate color data between color profiles whenever an image is captured, edited, or viewed. For example, a digital camera includes its own built-in color profile based on its sensor's performance characteristics and embeds that color profile into every photograph it takes. When opened by software like Photoshop, the color management system converts colors from the embedded profile to a generic working color profile for editing, while also converting it to the monitor's color profile for display. If necessary, the software adjusts those colors to fit within the monitor's gamut while maintaining its appearance as closely as possible. Finally, when printing the photo, it is converted one more time to the printer's color profile, using color mapping tables to translate color values from RGB to CMYK. NOTE: Camera RAW images are not given a color profile by the camera but are assigned one once imported into the photographer's editing software. Updated May 17, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/color_profile Copy

Color Space

Color Space A color space is a specific range of colors a single image or monitor can display. Each color space covers a slice of the visible spectrum provided by a given color model. The boundaries of a particular color space, and the colors within those boundaries, are referred to as its gamut. Color spaces can limit the colors used in an image to only those that a device is able to display, efficiently using the color spectrum to not waste information on out-of-gamut colors. The most common color space is sRGB, which is considered the bare minimum standard that any computer should be able to show. Higher-end monitors — like those used by photo and video professionals, or HDR-capable televisions — can display a wider gamut and use more advanced color spaces. Digital cameras that save images directly to the JPEG format often require the photographer to choose between sRGB and Adobe RGB. Cameras that capture RAW photos allow the photographer to choose a color space later, during processing and editing. Most digital color spaces are based on the RGB color model, subdividing the available color spectrum into triangle-shaped slices. The larger the triangle, the wider the color gamut that color space can display. For example, the sRGB color space is comparatively small and can display fewer colors than bigger color spaces like Adobe RGB. Some other color spaces, like ProPhoto RGB, have such a large gamut that they can theoretically include colors outside the visible spectrum. However, a wider gamut also means larger steps between colors. For example, if you save an image using the Adobe RGB color space with only 8 bits per channel, the colors may be more vibrant at their extremes than the smaller sRGB space, but with increased banding in gradient areas. By increasing the color depth to 10 or 12 bits per channel, you can include more variation within a color space. Updated April 4, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/color_space Copy

Column

Column A column is a vertical group of values within a table. It contains values from a single field in multiple rows. In databases, columns may be defined as individual fields within a table. Each field has a name, such as Name, Address, or Phone Number. Therefore, when multiple values from a column are selected, they will all have similar information, such as a list of phone numbers. When defining columns in databases and spreadsheets, it is often possible to specify the type of data, such as a string, number, or date. This helps ensure all the data within a given column has a similar format. NOTE: While it is easy to get rows and columns confused, just remember that columns are vertical (like the columns used in architecture), while rows are horizontal, like rows of text. Updated June 8, 2011 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/column Copy

Command Line Interface

Command Line Interface A command line interface (or CLI) is a text-based interface used for entering commands. In the early days of computing, before the mouse, it was the standard way to interact with a computer. While the graphic user interface (GUI) has largely replaced CLIs, they are still included with several major operating systems, such as Windows and OS X. There are many different types of command line interfaces, but the two most popular ones are DOS (for Windows) and the bash shell (for Linux and OS X). Each CLI uses its own command syntax, but they all function in a similar way. For example, every CLI has a command prompt, which is displayed when the interface is ready to accept a command. When you type a command, it shows up next to the command prompt, and when you press Enter, the command is executed. Below are some examples of command prompts for different command line interfaces, with the root folder as the current directory. Windows (DOS): C:> OS X (bash shell): My-iMac:/ me$ Linux (bash shell): [root@myserver /]# The standard way to change directories in most CLIs is to use the command cd, followed by the directory path. If you are using Windows, you can type cd C:Users to access the Users folder. If you're using OS X, you can type cd /Volumes/SSD/Users (assuming the drive name is "SSD"). A few other commands are identical between DOS and the bash shell, but each CLI supports many different commands as well. For example, to list the contents of the current directory, you would type dir in DOS and ls in the bash shell. Most people prefer a standard graphical user interface to a command line one. However, some operations can actually be completed faster using a keyboard instead of a mouse. Therefore, CLIs are often used by network administrators and webmasters for common tasks like transferring files and checking server status. NOTE: A command line interface is sometimes referred to as a console or terminal window. OS X includes a utility called "Terminal" that functions as the CLI for OS X. Updated August 26, 2014 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/command_line_interface Copy

Command Prompt

Command Prompt A command prompt is part of a computer's text-based command line interface. The prompt appears as user and directory information following by a specific symbol and text cursor, indicating that the computer is ready for the user to enter commands. Most operating systems provide access to a command prompt as an alternative to its graphical user interface. Unix, Linux, and macOS users can access the command prompt using the Terminal app, while Windows users can access it by opening the Command Prompt utility, cmd.exe. The command prompt often includes several pieces of important information. On Unix, Linux, and macOS, it starts with the username of the current user, followed by the computer name. After that, it includes the current directory where it will carry out commands; by default, the command prompt starts in the user's home directory, indicated by a ~ symbol. Windows formats its command prompt differently, omitting the user and computer name and starting with the full path of the current directory (including the drive letter). Finally, the command prompt ends with a symbol separating it from the commands the user enters, like a $, %, or >. A typical Unix command prompt follows this pattern: username@computername:/directory$ A macOS command prompt follows a similar pattern, but with spaces between elements: username@Computer-Name directory % Finally, the Windows command prompt remains the same as the DOS prompt: C:UsersUsername> The Windows Command Prompt utility (cmd.exe) Using the command prompt to issue commands requires memorization of some syntax and commands. While you can consult online guides or written documentation for commands that you won't use that often, it is still helpful to be familiar with at least some basic navigation commands. The cd command (used by Unix-based operating systems and Windows) lets you change the directory you're currently working in, either by entering a full path or a relative path from the current location. To see the files and folders within the current directory, you can use the ls command on Unix, Linux, and macOS, or the dir command on Windows. Updated December 8, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/command_prompt Copy

Commercial Software

Commercial Software Computer software comes in three different flavors: freeware, shareware, and commercial software. Freeware is free to use and does not require any payment from the user. Shareware is also free to use, but typically limits the program's features or the amount of time the software can be used unless the user purchases the software. Commercial software requires payment before it can be used, but includes all the program's features, with no restrictions or time limits. Commercial software programs typically come in a physical box, which is what you see displayed in retail stores. While it's true that the software boxes are not as big as they used to be, they still contain the software CD or DVD and usually a "getting started" manual along with a registration key used for registering the product. Most commercial software programs ask that the user register the program so the company can keep track of its authorized users. Some commercial software programs, such as newer versions of Microsoft and Adobe programs, require the user to register the programs in order to continue using them after 30 days. While most commercial software programs are sold in the physical box, many software titles are now available as downloads. These downloads are typically made available from the company's website. The user pays for the program directly on the website and instead of receiving the software in the mail, the user downloads it to his computer. Another popular way of purchasing commercial software online is simply paying for a registration key, which unlocks the features of a shareware program. This upgrades the shareware program to the commercial version, which removes any feature limitations from the shareware version. Updated December 11, 2007 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/commercialsoftware Copy

Compact Flash

Compact Flash Compact Flash, often abbreviated CF, is a removable memory card format that uses nonvolatile flash memory. Digital cameras and other handheld electronic devices use CF cards to store and transfer digital photos, video, and other data. SanDisk introduced Compact Flash in 1994, and over time it became one of the most common removable memory card formats. However, it is becoming less common as newer formats like SD, microSD, and CFexpress become more popular, phasing out the CF slot in new digital cameras. Compact Flash memory cards are available in two physical sizes, known as Type I and Type II. Type I CF cards are 3.3 mm thick, while Type II are 5 mm thick. Type II cards can use that extra space to add features to the card, like Wi-Fi or Bluetooth wireless radios, to allow data transfers between cameras and computers without removing the card. Type I cards can fit into Type II slots, so a camera with a Type II CF slot can accept any CF card. Both types use a 50-pin connector based on a subset of the 68-pin PCMCIA connector. External card readers allow computers to read CF cards. A SanDisk Compact Flash card, showing its 50-pin connector During the height of its popularity, the Compact Flash format had several benefits over other types of memory cards. It was physically larger than other formats, but that meant that it was also more durable. It was available in higher capacities than other formats (up to 512 GB) and provided faster transfer speeds (up to 160 MB/s). Most big camera makers (including Canon and Nikon) included CF card slots on their consumer- and professional-level digital cameras. Over time, however, the SD card format became more popular due to its smaller size, which allowed for smaller camera bodies. In 2017, a successor format, CFexpress, was introduced with significantly faster read and write speeds necessary for high-resolution 4K and 8K video recording. Updated September 12, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/compact_flash Copy

Compatibility Layer

Compatibility Layer A compatibility layer is a software interface that allows applications written and compiled for one operating system or hardware architecture to run on a different host system. It receives API calls and other system functions designed for one environment and translates them into calls that the host system can understand. Compatibility layers can serve a similar function as emulation and virtualization by allowing software written for one environment (for example, Windows on an x86 processor) to run in either a different operating system on similar hardware (Linux on an x86 processor) or a similar operating system on a different hardware architecture (Windows on an ARM processor). They do this by intercepting every system API call the program tries to make to its original environment and converting them into the equivalent calls to the new host environment. Some notable compatibility layers include Wine (which allows Windows programs to run on Linux by implementing the Windows API), Rosetta 2 on macOS (which allows macOS apps compiled for x86 to run on Apple Silicon), and WOW64 on Windows (which translates Windows apps built for x86 to run on x86-64 and ARM processors). Running software in a compatibility layer often uses fewer system resources than emulating another environment or running a virtual machine. However, some software may experience errors or require additional configuration to work properly when using a compatibility layer. Comparison to Emulation and Virtualization Emulators, virtualization, and compatibility layers are all often used to run another environment's software. Each method accomplishes that task differently. An emulator uses software to recreate both a device's hardware and its software to emulate the entire environment. Since emulating hardware devices in software requires significant system resources, a host system needs to be significantly faster than the hardware it's emulating to achieve similar performance. A compatibility layer meant to translate between two hardware platforms will include a hardware emulator, using it only as needed instead of constantly emulating the entire environment. A virtual machine simulates an entire computer on the host machine's hardware. It runs a copy of an operating system and uses a software layer to translate virtualized hardware calls to the host machine's hardware. A compatibility layer only translates the calls it needs to, doing so without simulating hardware or software calls that it does not need to. Updated November 7, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/compatibility_layer Copy

Compile

Compile To compile a program is to convert it from human-readable source code into an executable file. Compiling a program also packages assets like images and icons into the program. It is necessary to compile a program before a computer can run it. When a developer writes a program, they do so in a programming language designed to be easy for them to write, read, and maintain. However, computers cannot run a program directly from source code — the CPU can only understand instructions in its native, low-level machine language. Compiling a program converts the instructions in the source code into a corresponding set of instructions in machine language, then encodes it into a binary executable file. Compiling a program translates source code files into an executable file Software development kits (SDKs) include programs called compilers for developers to compile their projects. A compiler converts source code into an executable file for a single operating system and processor architecture at a time — for example, Windows on x86-64 or Unix on ARM64. Some compilers allow a developer to include machine code for multiple architectures in a single file — for example, a universal binary for macOS that can run on both Intel and Apple Silicon processors — by separately compiling for each processor architecture, then combining them into a single packaged executable. NOTE: Programming languages that don't require compiling before running are known as "interpreted" languages. Instead, an "interpreter" program translates a program's source code into machine language at runtime. For example, a JavaScript program is not compiled but instead runs through a separate JavaScript interpreter. Updated March 31, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/compile Copy

Compiler

Compiler A compiler is a software program that compiles program source code files into an executable program. Integrated development environments (IDEs) include compilers as part of their programming software packages. The compiler takes source code files written in a high-level language, such as C, BASIC, or Java, and translates that code into a low-level language known as machine code. This code is specific to the selected processor type, such as an Intel x86-64 or ARM. The resulting program's underlying code is understood and executed by the processor when run from the operating system. Some compilers add extra optimizations while they compile, making the program run faster at the cost of a longer compilation process. These optimizations can reduce or eliminate the amount of assembly code (a more-efficient low-level language) that a programmer needs to write, especially when compiling for processors with complex instruction sets. Once a compiler compiles source code files into a program, the program cannot be modified. Therefore, a programmer must update the source code itself and recompile the program. Fortunately, most modern compilers can detect where changes were made and only recompile the modified files, which saves programmers a lot of time. Updated February 9, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/compiler Copy

Component

Component Computers are made up of many different parts, such as a motherboard, CPU, RAM, and hard drive. Each of these parts are made up of smaller parts, called components. For example, a motherboard includes electrical connectors, a printed circuit board (PCB), capacitors, resistors, and transformers. All these components work together to make the motherboard function with the other parts of the computer. The CPU includes components such as integrated circuits, switches, and extremely small transistors. These components process information and perform calculations. Generally speaking, a component is a element of a larger group. Therefore, the larger parts of a computer, such as the CPU and hard drive, can also be referred to as computer components. Technically, however, the components are the smaller parts that make up these devices. Component may also refer to component video, which is a type of high-quality video connection. A component connection sends the video signal through three separate cables — one for red, green, and blue. This provides better color accuracy than composite video (typically a yellow connector), which combines all the color signals into a single cable. Updated in 2006 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/component Copy

Compression

Compression Compression, or "data compression," is used to reduce the size of one or more files. When a file is compressed, it takes up less disk space than an uncompressed version and can be transferred to other systems more quickly. Therefore, compression is often used to save disk space and reduce the time needed to transfer files over the Internet. There are two primary types of data compression: File Compression Media Compression File compression can be used to compress all types of data into a compressed archive. These archives must first be decompressed with a decompression utility in order to open the original file(s). Media compression is used to save compressed image, audio, and video files. Examples of compressed media formats include JPEG images, MP3 audio, and MPEG video files. Most image viewers and media playback programs can open standard compressed file types directly. File compression is always performed using a lossless compression algorithm, meaning no information is lost during the compression process. Therefore, a compressed archive can be fully restored to the original version when it is decompressed. While some media is compressed using lossless compression, most image, audio, and video files are compressed using lossy compression. This means some of the media's original quality is lost when the file is compressed. However, most modern compression algorithms can compress media with little to no loss in quality. Updated April 7, 2011 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/compression Copy

Computer

Computer A computer is a programmable machine capable of executing a programmed list of instructions, accepting input, and returning output. While many mechanical devices can technically function as computers, the term commonly refers to digital electronic computers. All computers are a combination of hardware and software that are useless without each other. The term "hardware" refers to the physical parts of a computer, while "software" refers to the programs that tell the hardware what to do. All computers include a common set of hardware components: A motherboard is a printed circuit board that connects every other component via communication pathways called buses. A CPU performs data processing functions and serves as the "brain" of the computer. System memory stores temporary data for the CPU to access quickly, like active programs and open files. A storage disk provides long-term data storage, keeping applications and files available for access when needed. Other components can expand the computer's capabilities. Video cards connect a computer to a monitor, draw the user interface, render 3D graphics, and decode compressed video. Input devices like keyboards, mice, and touchscreens give a computer's user a way to interact with it and issue commands. Network adapters let a computer talk to other computers over a local network or the internet. USB ports and other external interfaces allow you to connect peripherals. Four common computer form factors — a laptop, all-in-one, tablet, and smartphone The most important software running on a computer is its operating system. This software communicates directly with the computer's hardware and allows other software applications to run. The combination of a computer's hardware architecture and operating system is known as a platform. Computers that share a platform can often run the same programs as each other. Computer Form Factors Computers come in several shapes and sizes, known as form factors. Some form factors allow a computer's owner to customize its hardware configuration, while others are tightly-integrated devices. Desktop computers are modular personal computers made up of discrete components assembled inside a chassis. A desktop computer's owner may replace or upgrade hardware components to improve a computer's performance. Desktop computers connect to external displays and input devices. Laptops are tightly integrated portable personal computers whose foldable cases include a monitor, keyboard, and trackpad. They include rechargeable batteries that allow them to run without a constant power connection. Unlike desktops, the hardware is often not replaceable or upgradeable. All-in-one computers are a hybrid between desktops and laptops. They're tightly integrated like laptops, and built into a chassis with a large monitor. Like desktops, they require separate input devices like keyboards and mice. They are not portable, but are more compact than desktop computers. Smartphones and tablets are even more compact than laptops, integrating a computer and battery behind a touchscreen. While they support external keyboards, most interaction with a smartphone or tablet happens through the touchscreen. Rack-mounted computers are often used as dedicated servers. These computers use flat enclosures that fit into standard rack mounts, which can store several computers stacked vertically. These computers often don't connect to monitors, keyboards, or mice — instead, they are controlled and monitored remotely over a network. Mainframes and supercomputers are large-scale, high-powered computers designed for computationally-intensive tasks. They can perform far more calculations per second than a personal computer and are used by large organizations for complex data analysis. Updated May 31, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/computer Copy

Computer Ethics

Computer Ethics Ethics is a set of moral principles that govern the behavior of an individual or group of people. Computer ethics is the application of moral principles to the use of computers and the Internet. Examples include intellectual property rights, privacy policies, and online etiquette, or "netiquette". Computers make it easy to duplicate and redistribute digital content. However, it is ethical to respect copyright guidelines. When using software, it is important to understand and follow the license agreement, or SLA. Using commercial software without paying for a license is considered piracy and is a violation of computer ethics. Hacking, or gaining unauthorized access to a computer system, is also an unethical way to use computers. As technology advances, computers and the Internet have an increasing impact on society. Therefore, computer ethics must be part of the discussion whenever creating new technologies. A modern example is how artificial intelligence affects existing jobs and human communication. When computer ethics is part of the conversation, it helps ensure new technologies positively affect society. Updated January 22, 2021 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/computer_ethics Copy

Computer Science

Computer Science Computer science is the study of computers and computing concepts. It includes both hardware and software, as well as networking and the Internet. The hardware aspect of computer science overlaps with electrical engineering. It covers the basic design of computers and the way they work. A fundamental understanding of how a computer "computes," or performs calculations, provides the foundation for comprehending more advanced concepts. For example, understanding how a computer operates in binary allows you to understand how computers add, subtract, and perform other operations. Learning about logic gates enables you to make sense of processor architecture. The software side of computer science covers programming concepts as well as specific programming languages. Programming concepts include functions, algorithms, and source code design. Computer science also covers compilers, operating systems, and software applications. User-focused aspects of computer science include computer graphics and user interface design. Since nearly all computers are now connected to the Internet, the computer science umbrella covers Internet technologies as well. This includes Internet protocols, telecommunications, and networking concepts. It also involves practical applications, such as web design and network administration. NOTE: While computer science (lowercase) refers to the general study of computers, Computer Science (capitalized) is an academic major offered at many colleges and universities. It is often abbreviated "CS" or "CompSci." Examples of Computer Science courses include: Introduction to Computing Fundamental Programming Concepts Data Structures Analysis of Algorithms Computing Theory Computer Science classes may also be specific to certain industries or topics. Examples include: Video Game Design Computer Graphics Database Systems Cryptography Networking Concepts Like other educational disciplines, Computer Science courses vary from beginner to advanced. The number of a Computer Science course typically indicates the level of the class. For example, an introductory class may be labeled CS 102, while an advanced class may be labeled CS 431. Updated August 22, 2014 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/computer_science Copy

Concatenation

Concatenation Concatenation is "the action of linking things together in a series" (Oxford English Dictionary). In computer programming terms, it refers to a function that links two or more text strings together into a single string. Databases and spreadsheets also use concatenation functions to merge data from separate fields and cells. Most programming languages include several concatenation methods to combine strings. When used with text strings, the + operator often works, but special concatenation functions can provide developers with more control. For example, both of the following JavaScript samples join two variables, adding a space in between: fullName = firstName+" "+lastName; fullName = firstName.concat(" ", lastName); While the + operator is most common, some languages use other operators. For example, Perl uses . to concatenate strings, while Visual Basic uses &. Two cells in a spreadsheet joined using a concatenate function Concatenation functions can also combine strings in database fields and spreadsheet cells. For example, if a customer information table in an SQL database keeps the first and last names in separate fields, you can use the CONCAT() function to select both and format them as a single string. Spreadsheet applications like Microsoft Excel can use the CONCATENATE() function to select the values of two referenced cells and display them as one joined value. For example, CONCATENATE(B2," ",C2) joins the contents of cells B2 and C2, with a space in between. Updated June 2, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/concatenation Copy

Configuration

Configuration A system configuration refers to the technical specifications (or "tech specs") of a device. For a computer, the primary specs include the CPU type and speed, system memory (or RAM), graphics card (GPU), storage device type and capacity, and operating system. A detailed configuration may include the motherboard, network adapters (including Ethernet and Wi-Fi capabilities), Bluetooth connectivity, and I/O ports. Below is an example configuration of a Dell Alienware gaming PC. Alienware Aurora R16 desktop computer CPU: Intel Core i9 14900KF (68 MB cache, 24 cores, up to 6.0 GHz) GPU: NVIDIA GeForce RTX 4090, 24 GB GDDR6X RAM: 32 GB (2 x 16 GB, DDR5, 5600 MT/s) Storage: 2 TB, M.2, PCIe NVMe SSD OS: Windows 11 Home System configurations also apply to virtual environments, which include similar specifications. Unlike laptops and (desktop PCs||desktop_computer), cloud configurations can update dynamically, adding RAM, storage, and processing power based on resources available across multiple systems. Understanding core specs like CPU, GPU, RAM, and storage is helpful when choosing a new computer or virtual system. For example, if you mainly use your PC for browsing the web and writing documents, you don't need a high-end CPU or lots of RAM, like someone who does video editing. If you play games on your PC, you might need a high-end video card, whereas an audio engineer only needs basic graphics capabilities. Generally, it's best to choose a system with slightly better specs than you need so that it will be sufficient for your current and future computing tasks. Updated October 11, 2024 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/configuration Copy

Console

Console A console is the combination of a monitor and keyboard. It is a rudimentary interface in which the monitor provides the output and the keyboard is used for input. While any computer with a monitor and keyboard may be considered a console, the term most often refers to a system used to control one or more servers. Early consoles in the 1970s and 1980s provided a text-only "command line" interface, in which a network admin could type commands at a command prompt. Modern consoles often provide a graphical interface that can be used to control machines on a local network (LAN) or provide remote access to remote systems. These consoles typically include a mouse for navigating graphical interfaces. The terms "console" and "terminal" are often used synonymously. However, "terminal" may also be used to describe the software that runs on a console, such as a command line interface or remote access program. Mac OS X includes both a Terminal program that provides a command line interface, and a Console utility that displays system logs and diagnostic reports. NOTE: A console may also refer to other types of hardware besides computer interfaces. For example, gaming systems such as the PlayStation, Xbox, and Wii, are called video game consoles, while multi-channel audio mixing boards are called mixing consoles. Updated March 12, 2012 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/console Copy

Constant

Constant In mathematics, a constant is a specific number or a symbol that is assigned a fixed value. For example, in the equation below, "y" and "x" are variables, while the numbers 2 and 3 are constants. y = 2x - 3 Constants are also used in computer programming to store fixed values. They are typically declared at the top of a source code file or at the beginning of a function. Constants are useful for defining values that are used many times within a function or program. For example, in the C++ code below, min and max are declared as constants. const int min = 10; const int max = 100; By using constants, programmers can modify multiple instances of a value at one time. For example, changing the value assigned to max in the example above will modify the value wherever max is referenced. If the number 100 was used instead of max, the programmer would have to modify each instance of "100" individually. Therefore, it is considered good programming practice to use constants whenever a fixed value is used multiple times. Updated May 3, 2012 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/constant Copy

Container

Container A container is a software package that contains everything the software needs to run. This includes the executable program as well as system tools, libraries, and settings. Containers are not installed like traditional software programs, which allows them to be isolated from the other software and the operating system itself. The isolated nature of containers provides several benefits. First, the software in a container will run the same in different environments. For example, a container that includes PHP and MySQL can run identically on both a Linux computer and a Windows machine. Second, containers provide added security since the software will not affect the host operating system. While an installed application may alter system settings and modify resources, such as the Windows registry, a container can only modify settings within the container. This makes containers ideal for software testing and development. Containers also eliminate installation issues, including system conflicts, version incompatibilities, and missing dependencies. The result is a "works on all machines" solution, which is ideal for both developers and end users. It also makes the jobs of network administrators easier, since they can deliver containers to a multiple users without having to worry about compatibility issues. Containers vs Virtual Machines Containers are similar to virtual machines (virtualization) since they include everything needed to run in a single package. However, unlike virtual machines (VMs), containers do not include a guest OS. Instead containers run on top of a "container platform," like Docker, which is installed on an operating system. Containers are "lightweight," meaning they require far less disk space than VMs. Additionally, multiple containers can run side-by-side on the same container platform. Updated August 21, 2017 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/container Copy

Contextual Menu

Contextual Menu A contextual menu, also known as a "right-click menu" or "context menu," is a menu that appears when a user right-clicks something. The options in the menu are "contextual," because only commands relevant to the clicked-on object are displayed. All modern operating systems with graphical user interfaces (GUIs) include contextual menus as part of their interface, including mobile operating systems. Contextual menus provide a shortcut to many commands that are available elsewhere but are specifically relevant to what you right-clicked on. For example, if you right-click a file on your desktop, you'll see commands that let you open it, rename it, or view its properties. Right-click the desktop itself, and you'll instead see options to change the wallpaper or rearrange desktop icons. Right-click some text in Microsoft Word, and you'll see another set of commands that help you copy and paste text, change font and paragraph settings, or look up synonyms for a word. A contextual menu in macOS when right-clicking a video file While right-clicking is the most common way to open a contextual menu, it's not the only way. On macOS, holding the Control key while clicking something opens a contextual menu. On Windows and Linux, pressing the Menu key on the keyboard opens a contextual menu on the selected object. On both iOS and Android mobile devices, pressing and holding your finger on the touchscreen opens a contextual menu. Updated October 20, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/contextual_menu Copy

Control Panel

Control Panel The Control Panel is a feature of the Windows operating system that allows the user to modify system settings and controls. It includes several small applications, or control panels, that can be used to view and change hardware or software settings. Some examples of hardware control panels are Display, Keyboard, and Mouse settings. Software control panels include Date and Time, Power Options, Fonts, and Administrative Tools. Many control panels are included as part of the Windows operating system, but others can be installed by third-party applications or utilities. For example, if you add a new mouse to your computer, it may come with a CD for installing a control panel specific for that mouse. Some graphics cards may also install an additional control panel that gives the user greater control over the computer's visual settings. Regardless of when control panels are installed, they can always be found within the Control Panel folder. The Windows Control Panel can be accessed by clicking the Start menu and selecting Control Panel. It is also available in the "Other Places" section of the window's sidebar when you open My Computer. In Windows XP and Windows Vista the Control Panel can be viewed in either Category View or Classic View. Category View arranges the control panels into sections, while Classic View shows them all at once. While the Category View is designed to make locating different settings easier, people familiar with most of the control panels often find the Classic View more efficient. Control Panels were also used for many years by the Mac OS, through Mac OS 9. However, with the introduction of Mac OS X, control panels were consolidated into a single interface called System Preferences. The control panels themselves are now called "Preference Panes" in Mac OS X. They can be accessed by selecting "System Preferences" from the Apple menu or by clicking the System Preferences icon in the Dock. Updated October 18, 2007 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/controlpanel Copy

Control Unit

Control Unit A control unit (CU) is an integrated circuit in a processor that controls the input and output. It receives instructions from a program, then passes them to the arithmetic logic unit (ALU). The ALU performs the appropriate calculations and sends the resulting values back to the control unit. The control unit sends these values to the corresponding program as output. A typical control unit is comprised of several logic gates and includes two important components: Program Counter (PC) Instruction Register (IR) The program counter loads individual instructions from memory and stores them sequentially. The instruction register decodes these instructions and converts them to commands for the CPU. After each instruction, the CU increments the program counter and fetches the next instruction. Control units operate at the clock speed of the corresponding CPU. Therefore, the control unit of a 3 GHz processor can handle three billion operations per second. Updated October 31, 2020 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/control_unit Copy

Controller Card

Controller Card A controller card, sometimes referred to simply as a "controller," is a computer hardware component that creates an interface between a computer’s main system motherboard and other hardware components. Some controllers will be integrated directly into the motherboard, while others may be added on as expansion cards. Motherboards have several types of controllers built in as dedicated chips. These controllers are necessary for integrated components to communicate with each other. For example, the memory and storage controllers allow other parts of the computer access to the RAM and disk drives. Built-in graphics and audio controllers create the interface between the motherboard and the video and audio ports, allowing you to connect monitors and audio devices. A network controller will create the interface between the motherboard and a built-in Ethernet port. USB and Thunderbolt controllers allow the motherboard to communicate with devices plugged into those ports. HP Thunderbolt 3 PCIe controller card Even though most motherboards have most necessary controllers already integrated, you can add controller cards that add extra ports and new connectivity options. Controller cards plug into one of a computer’s expansion slots, typically a PCIe slot. For example, you can add more USB ports to a computer by adding a USB controller card or add the capacity for a RAID storage array by adding a disk array controller. Updated September 21, 2022 by Brian P. Reviewed by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/controller_card Copy

Cookie

Cookie A cookie is a small amount of data generated by a website and saved by your web browser. Its purpose is to remember information about you, similar to a preference file created by a software application. While cookies serve many functions, their most common purpose is to store login information for a specific site. Some sites will save both your username and password in a cookie, while others will only save your username. Whenever you check a box that says, "Remember me on this computer," the website will generate a login cookie once you successfully log in. Each time you revisit the website, you may only need to enter your password or you might not need to log in at all. Cookies are also used to store user preferences for a specific site. For example, a search engine may store your search settings in a cookie. A news website may use a cookie to save a custom text size you select for viewing news articles. Financial websites sometimes use cookies to store recently viewed stock quotes. If a website needs to store a lot of personal information, it may use a cookie to remember who you are, but will load the information from the web server. This method, called "server side" storage, is often used when you create an account on a website. Browser cookies come in two different flavors: "session" and "persistent." Session cookies are temporary and are deleted when the browser is closed. These types of cookies are often used by e-commerce sites to store items placed in your shopping cart, and can serve many other purposes as well. Persistent cookies are designed to store data for an extended period of time. Each persistent cookie is created with an expiration date, which may be anywhere from a few days to several years in the future. Once the expiration date is reached, the cookie is automatically deleted. Persistent cookies are what allow websites to "remember you" for two weeks, one month, or any other amount of time. Most web browsers save all cookies in a single file. This file is located in a different directory for each browser and is not meant to be opened manually. Fortunately, most browsers allow you to view your cookies in the browser preferences, typically within the "Privacy" or "Security" tab. Some browsers allow you to delete specific cookies or even prevent cookies from being created. While disallowing cookies in your browser may provide a higher level of privacy, it is not recommended since many websites require cookies to function properly. NOTE: Since cookies are stored in a different location for each web browser, if you switch browsers, new cookies will need to be created. Updated July 9, 2011 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cookie Copy

Copilot

Copilot Microsoft Copilot is an assistive AI tool that answers questions and provides suggestions via a conversational chat interface. It can also summarize documents, write new content, and generate custom images based on user input. The digital companion helps with everyday tasks, including personal and work-related ones. For example, it can give you dinner recipe ideas or tips for improving your golf swing. If you need help writing a resume or cover letter, Copilot can produce a template to get you started. Microsoft Copilot is "your everyday AI companion" Technology Copilot uses several generative AI models to process user input. Below are three foundational technologies as of June 2024: Microsoft Prometheus - Microsoft's proprietary large language model (LLM) GPT-4 (Generative Pre-Trained Transformers version 4) - the same models used by OpenAI's ChatGPT DALL-E 3 - an AI model that generates and modifies images from textual input Like other generative AI services, Microsoft Copilot is a tool that "learns" over time. It utilizes machine learning to enhance its responses based on user feedback and follow-up questions, helping it adapt to users' needs. Availability Copilot is integrated into Windows 11 and Microsoft 365 applications. It is also available as a standalone app and on the web at copilot.microsoft.com. When using the Bing search engine, you may see Copilot suggestions alongside the search results. The standard version of Copilot is free to use. If you want priority access to the latest models and faster responses, Copilot Pro is available as a monthly subscription. Updated June 20, 2024 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/copilot Copy

Copy

Copy To copy text or data is to create a duplicate in the system clipboard. Once you've copied something, you can paste it into another part of the same document, another document in the same program, or another program entirely. Copying data is similar to cutting it, but cutting removes the data from its original spot, and copying it leaves it in place. You can select the Copy command from a program's Edit menu or use the keyboard shortcut Control + C (on Windows) / Command + C (on macOS). The Copy, Cut, and Paste commands are some of the earliest interface metaphors that came with graphical user interfaces. They are meant to remind computer users of physical interactions with paper documents — copying a page of paper on a photocopier to create duplicates while preserving the original, destructively cutting text out of a page using scissors or a knife, and placing either the cut original or copied duplicate onto another page using paste. Thankfully, copying text in a digital document is much easier through menu commands and keyboard shortcuts. The Copy button on the Microsoft Word ribbon While a piece of copied data is on the system clipboard, you can paste it anywhere that can accept that data type. For example, you can paste text anywhere you can enter text, or paste image data in any image editor or desktop publishing app. You can also copy and paste files in your file browser to create duplicates in another folder or on another disk. You can paste the same data multiple times since pasting does not remove data from the clipboard. However, copying something new replaces the contents of the clipboard. Some operating systems allow you to go back through the clipboard's history to recover something you had copied earlier, but this requires extra steps and not an easy keyboard shortcut. Updated December 5, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/copy Copy

Copy"

Copy"

Copyright

Copyright Copyright is a legal means of protecting an author's work. It is a type of intellectual property that provides exclusive publication, distribution, and usage rights for the author. This means whatever content the author created cannot be used or published by anyone else without the consent of the author. The length of copyright protection may vary from country to country, but it usually lasts for the life of the author plus 50 to 100 years. Many different types of content can be protected by copyright. Examples include books, poems, plays, songs, films, and artwork. In modern times, copyright protection has been extended to websites and other online content. Therefore, any original content published on the Web is protected by copyright law. This is important in the digital age we live in, since large amounts of content can be easily copied and pasted. So how do you obtain copyright protection? Fortunately, in most countries, copyright protection is automatic. This means whenever you publish original content, it is automatically protected by copyright law. For example, if you post a blog on the Internet, your content is automatically covered by copyright. In most cases, this type of copyright protection is all that is necessary. However, if you want others to know your content is copyright protected, you can post the copyright logo (©) next to your name on any Web pages that include your original content. You may also want to include the years you have owned the content. Below is an example of a copyright line: Copyright © 2007-2009 [your name]. In situations where it is critical to protect an author's rights, many countries provide copyright registration, which allows authors to register copyrighted content with a central agency. This makes it easier to prove ownership of content if it is ever disputed. Copyright provides a helpful means of protecting original content. It serves to give people credit for the work they do, which is something we can all appreciate. Therefore, if you ever consider copying someone else's content, think of how it would make you feel if someone copied your original work and published it as their own. If you ever would like to use another person's content, make sure to ask the author for permission first. And always give credit where credit is due. Updated September 8, 2009 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/copyright Copy

Copyright Infringement

Copyright Infringement A copyright infringement is a violation of an individual or organization's copyright. It describes the unauthorized use of copyrighted material, such as text, photos, videos, music, software, and other original content. In the computer industry, copyright violations often refer to software programs and websites. Software is usually distributed under a certain type of license agreement, or SLA. This license defines the terms of use, including whether or not the software can be distributed to other users. For example, open source programs are free to use and may often be redistributed without limitations. Commercial software, however, must be purchased and cannot be redistributed. Using commercial software without paying for it is a copyright infringement and as commonly known as piracy. Websites that contain original content are automatically protected under international copyright law. In other words, you cannot copy the content of one website and publish it on another site without the author's permission. Reposting text, images, videos, audio clips, or any other content found on the Web without permission constitutes a copyright infringement. Legal penalties for violating website copyrights depend on the extent and damages caused by the copyright violation. Since we live in a digital age, copying content is often as simple as a copy and paste operation. This makes it possible for one person to copy and republish content in a few minutes that may have taken another person several years to create. Therefore, In 1998, the United States Congress took steps to defend intellectual property by passing the Digital Millennium Copyright Act, commonly known as DMCA. This law defines specific types of digital copyright infringements and establishes serious penalties for violators. NOTE: If you ever want to use or republish content from the Web, you should always ask the author for permission and include an appropriate reference and link to the original content. Updated November 13, 2012 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/copyright_infringement Copy

CORS

CORS Stands for "Cross-Origin Resource Sharing." CORS allows scripts on webpages to request resources from other domains. Most web browsers block these types of requests by default for security purposes. A webpage can request resources from another domain — as long as the requests come from the HTML. For example, the section may reference resources, such as CSS files, fonts, and JS files other domains. Examples include Google Analytics scripts, jQuery libraries, and fonts hosted on another server. Similarly, the can request images from a CDN or other domain. Cross-origin resource requests in the HTML do not require CORS permissions. When a script or iframe element makes a cross-origin request, CORS is required. For example, an AJAX method – which runs after the page is loaded – cannot request a resource from another domain. CORS overrides this default browser setting and allows the request to go through. CORS is implemented using "access control" HTTP headers. A server admin can add or modify the response headers, which are sent to a client's browser when a webpage is accessed. These settings, which can be applied to Apache and IIS servers, may be site-specific or server-wide. Below are common request and response headers: CORS Request Headers: Origin Access-Control-Request-Method Access-Control-Request-Headers CORS Response Headers: Access-Control-Allow-Origin Access-Control-Allow-Methods Access-Control-Expose-Headers CORS Example If a script on techterms.com requests a resource from sharpened.com using a GET action, it may send the following request headers: Origin: https://techterms.com Access-Control-Request-Method: GET To allow the request, sharpened.com may respond with the following headers: Access-Control-Allow-Origin: https://techterms.com Access-Control-Allow-Methods: GET Access-Control-Allow-Origin can be set to specific domains or a wildcard using an asterisk (*). The wildcard setting allows cross-resource requests from all domains, which may be a security risk. Access-Control-Allow-Methods can be set to PUT, POST, DELETE, and others, including a wildcard (*) setting that allows all methods. Updated November 3, 2020 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cors Copy

CPA

CPA Stands for "Cost Per Action." CPA is a performance-based online advertising model where advertisers pay publishers a fixed amount whenever a user completes a specified action. Unlike other models that pay for clicks or impressions, CPA focuses on conversions. The user must not only click on an ad but also complete a predetermined action, such as making a purchase, filling out a form, or downloading an app. For example, if a website visitor clicks an ad on a website, a click is recorded but not an action (or "conversion"). If the user takes the next step and completes a purchase, fills out a form, or downloads an app, the advertiser pays the publisher according to the agreed CPA rate. Generally, commissions for sales are higher than CPA rates for downloads and form submissions. CPA vs Other Advertising Models CPA is often compared to CPL (Cost Per Lead), but while CPL specifically refers to generating leads (like form submissions), CPA is broader and can include any predefined action. CPA may be risker for publishers than CPC (Cost Per Click) or CPM (Cost Per Thousand Impressions) since payment is contingent on users completing the desired action, which may not always happen even if a user clicks an ad. CPA is considered more cost-effective for advertisers since they only pay for tangible outcomes, making it ideal for businesses focused on ROI (Return on Investment). Updated August 27, 2024 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cpa Copy

CPC

CPC Stands for "Cost Per Click." CPC is a term used in online marketing that refers to how much an advertiser pays a website or ad network each time someone clicks one of their ads. It applies to ads displayed on search engine results pages, websites, social media, or anywhere else online. CPC is also known as PPC (Pay Per Click). When advertisers want to run an ad online, ad networks have them bid against other advertisers by setting a maximum CPC. The maximum CPC is part of a formula that looks at the keywords and demographics targeted, the advertiser's industry, how relevant the ad is, and when the ad runs. After the formula selects which ad to run, the ad network charges the advertiser just enough to win the bid, often less than the maximum CPC. The goal of CPC bidding, when compared to CPM (Cost Per Mille) bidding, is the focus on click-through rate, or CTR. Advertisers that use CPC bidding want people to click their ad to visit their website, often to sell a product or service. Advertisers using CPM bidding may instead just want their ads seen as widely as possible to build brand awareness without caring whether people click the ads. Updated October 9, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cpc Copy

CPL

CPL Stands for "Cost Per Lead." CPL is a term used in online marketing that refers to how much an advertiser pays a website or ad network each time they acquire a lead through an advertising campaign. This advertising model is also called "online lead generation." Once the ad campaign gathers leads, further marketing efforts attempt to convert those leads into customers. Advertisers running a campaign using a CPL pricing model tend to have a different focus than those using a CPC (Cost per Click) or CPM (Cost per Mille) model. Instead of paying for people to click or view an ad, a CPL model pays for leads — someone who has chosen to sign up to receive more information or express interest. First, an online ad sends a potential lead to the ad campaign's landing page. From there, they explicitly choose to share their information and express interest by the method set by the ad campaign — they may sign up for an email newsletter, a rewards program, a free trial, or otherwise share their personal information and express interest. These advertising campaigns tend to cost more, but the advertiser ends up with a more-valuable pool of leads. Leads who choose to sign up are more likely to become paying customers and even repeat customers. Updated November 4, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cpl Copy

CPM

CPM Stands for "Cost Per Mille." CPM, or "Cost Per Thousand Impressions," is a metric used in online advertising to define how much an advertiser pays for every 1,000 impressions of an ad. An impression is registered each time an ad is displayed, whether it's a banner ad, video, or other form of digital promotion. CPM is one of several key pricing models in digital advertising. Unlike models such as Cost Per Click (CPC) or Cost Per Lead (CPL) — where advertisers pay for user interactions (clicks or conversions) — CPM focuses on exposure. This makes it particularly useful for brand awareness campaigns, which aim to reach as many people as possible rather than driving immediate user actions. While CPM pricing is widely used in digital advertising, many advertisers also track metrics like Click-Through Rate (CTR) and conversion rate to assess the effectiveness of an ad beyond just impressions. Higher visibility (through CPM) can increase the likelihood of conversions, but it's easier to measure the return on ad spend (ROAS) using performance-based metrics like PPC or CPL. NOTE: Mille is Latin for "one thousand," which is where the term "CPM" comes from. Technically, CPM should be (RPM) or Revenue Per Mille from the publisher's side, but advertisers and publishers often use CPM and RPM interchangeably. Some advertising platforms display revenue per thousand impressions as eCPM (effective CPM) instead of RPM. Updated September 5, 2024 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cpm Copy

CPS

CPS Stands for "Classroom Performance System." CPS refers to a technology system that is used for educational purposes within a classroom. It includes both hardware and software that works together to create a modern, interactive learning environment for students. A typical CPS classroom setup includes a projector, a CPS Chalkboard, a computer running CPS software, and response pads that are given to the students. In a CPS-enabled classroom, the teacher can use a handheld CPS Chalkboard to give lessons or tests that are visually displayed on the projector. The students can interact with the lesson or test by using the response pads, which are similar to remote controls. Each response pad has several buttons (i.e. A through H), which can be used to answer test questions displayed on the projector in real-time. This allows each student to answer every question in a more systematic way than everyone yelling out the answer at one time. CPS has been shown to improve kids' learning capabilities and retention of subject matter. Because each student is able to interact with every aspect of the lesson, CPS can significantly increase students' interest in the subject matter. Considering how difficult it can be to keep kids' attention these days, many teachers may find CPS to be a welcome new technology. Updated May 31, 2007 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cps Copy

CPU

CPU Stands for "Central Processing Unit." The CPU is the primary component of a computer that processes instructions. It runs the operating system and applications, constantly receiving input from the user or active software programs. It processes the data and produces output, which may be stored by an application or displayed on the screen. The CPU contains at least one processor, which is the actual chip inside the CPU that performs calculations. For many years, most CPUs only had one processor, but now it is common for a single CPU to have at least two processors or "processing cores." A CPU with two processing cores is called a dual-core CPU and models with four cores are called quad-core CPUs. High-end CPUs may have six (hexa-core) or even eight (octo-core) processors. A computer may also have more than one CPU, which each have multiple cores. For example, a server with two hexa-core CPUs has a total of 12 processors. While processor architectures differ between models, each processor within a CPU typically has its own ALU, FPU, register, and L1 cache. In some cases, individual processing cores may have their own L2 cache, though they can also share the same L2 cache. A single frontside bus routes data between the CPU and the system memory. NOTE: The terms "CPU" and "processor" are often used interchangeably. Some technical diagrams even label individual processors as CPUs. While this verbiage is not incorrect, it is more accurate (and less confusing) to describe each processing unit as a CPU, while each processor within a CPU is a processing core. Updated July 11, 2014 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cpu Copy

Crash

Crash In computing, a crash is an unexpected termination of a process. Crashes can happen to individual applications as well as the operating system itself. Some crashes produce error messages, while other crashes may cause a program or the entire system to hang or freeze. When a crash occurs, it can cause a number of different problems. If you are typing a document in a word processor, for example, you may lose the changes you made since you last saved the document. If you are copying or downloading a file, the crash may produce a corrupt file. In some cases, a crash can even cause errors in the file system of your storage device. Since crashes create a negative user experience, software developers aim to create stable programs that do not crash. This involves removing bugs that produce undefined or infinite calculations and eliminating memory leaks. Some programs are even designed to handle crashes gracefully, generating detailed error messages if a "fatal error" occurs. Many productivity applications save your work periodically so you can recover your work after a crash. With older computers (before the turn of the century), when a program crashed, it often took down the whole system with it. This made restarting the computer a frequent task. Modern operating systems support multi-threading, which enables programs to run independently of each other. This allows the operating system and other programs to keep running when an application crashes. If the operating system itself crashes, however, you may still be forced to restart your computer. Updated June 19, 2014 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/crash Copy

CRM

CRM Stands for Customer Relationship Management. CRM refers to strategies, technologies, and practices businesses use to manage customer interactions and data. The goal is to enhance customer relationships, increase customer retention, and drive sales growth. In the current digital age, establishing and maintaining meaningful customer relationships can be difficult. This is especially true in e-commerce, where personal interactions are limited. CRM systems play a pivotal role in enhancing customer relationships through personalized communication and exceptional customer service. Customer Relationship Management solutions integrate various functions, such as sales, marketing, customer service, and support. By leveraging data analytics, businesses can gain valuable insights into customer behavior, preferences, and needs. These insights enable them to tailor their offerings and interactions to individual customers and clients. While analytics are helpful, effective CRM requires understanding and anticipating customers' needs. Even the most advanced tools can't replace genuine customer service. Updated July 11, 2024 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/crm Copy

Cron

Cron Cron is a job-scheduling system utility on Unix and Unix-like operating systems. Users can schedule tasks, known as "cron jobs," to run automatically at set intervals. Most Unix users schedule cron jobs to carry out system maintenance tasks, like deleting log files and creating backups, but a user can schedule any command or script they find useful. A user can schedule a cron job by creating a "crontab" file. A crontab file, or "cron table," specifies the command that will run and when to run it. A crontab file can contain a single cron job or multiple cron jobs. Each entry in a crontab has five variable fields that represent when to run the command, as well as one to specify the command itself: 1 2 3 4 5 * * * * * The minute (0-59) The hour (0-23) The day of the month (1-31) The month (1-12) The day of the week (0-6, Sunday to Saturday) Leaving an asterisk in place of a number runs the cron job at every instance of that variable. This allows the user to easily set a cron job to run every set number of minutes, hours, days, or months as necessary. Leaving every asterisk in place will run the cron job every minute. For example, the following cron job will echo the phrase "hello world" at 3:30 AM on the first day of every month: 30 3 1 * * echo hello world Updated November 14, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cron Copy

Crop

Crop To crop an image is to cut off part of the image along one or more sides. Photographers often crop an image to remove some unnecessary detail from the edge of a photo or to refine the photo's artistic composition. A crop tool is one of the most common features found in all photo editing applications. Cropping a photo after taking it is a common step for professional and amateur photographers alike. While the most common use for cropping is to remove unwanted details along the edge, it is also a helpful artistic tool. You can crop an image to adjust its composition and align the subjects in the frame according to the rule of thirds. You can alter an image's aspect ratio slightly to make it taller or wider, or switch between landscape and portrait orientations entirely. You can also use the crop tool to zoom in on a photo's subject, increasing its apparent size and emphasizing its importance. Cropping a photo in Apple Photos to change its aspect ratio and emphasize the subject When you enable a photo editing application's crop tool, you have several ways to crop. You can use the mouse to draw a freeform rectangle anywhere in the image to draw new borders, or make a slight adjustment by moving the original borders. You can also lock the crop tool to a specific aspect ratio to keep it uniform with other images. Cropping an image discards the cropped-out pixels entirely. You cannot restore this discarded information later, so you may want to create a backup of the image file before cropping. Since cropping removes pixels without adding new data, a cropped image will be smaller than the original. For example, if you start with a 12-megapixel photo and crop out a third of it, you're left with an 8-megapixel image. If you print the original and the cropped versions at the same DPI, the cropped version will be physically smaller; if you print them so that they're the same physical size, the cropped version may appear blurrier since it's stretching fewer pixels out over the same page size. NOTE: Some photo editors like Apple Photos automatically preserve the original image before any edits as a separate data fork in the image file, allowing you to restore the original if you don't like the changes you've made. Updated October 24, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/crop Copy

Cross-Browser

Cross-Browser When a software program is developed for multiple computer platforms, it is called a crossplatform program. Similarly, when a website is developed for multiple browsers, it is called a cross-browser website. The job of a Web developer would be much easier if all browsers were the same. While most browsers are similar in both design and function, they often have several small differences in the way they recognize and display websites. For example, Apple's Safari uses a different HTML rendering engines than Internet Explorer. This means the browsers may display the same Web page with slightly different page and text formatting. Since not all browsers support the same HTML tags, some formatting may not be recognized at all in an incompatible Web browser. Furthermore, browsers interpret JavaScript code differently, which means a script may work fine in one browser, but not in another. Because of the differences in the way Web browsers interpret HTML and JavaScript, Web developers must test and adapt their sites to work with multiple browsers. For example, if a certain page looks fine in Firefox, but does not show up correctly in Internet Explorer, the developer may change the formatting so that it works with Internet Explorer. Of course, the page may then appear differently in Firefox. The easiest fix for browser incompatibility problems is to use a more basic coding technique that works in both browsers. However, if this solution is not possible, the developer may need to add code that detects the type of browser, then outputs custom HTML or JavaScript for that browser. Making a cross-browser site is usually pretty simple for basic websites. However, complex sites with a lot of HTML formatting and JavaScript may require significant extra coding in order to be compatible with multiple browsers. Some developers may even generate completely different pages for each browser. While CSS formatting has helped standardize the appearance of Web pages across multiple browsers, there are still several inconsistencies between Web browsers. Therefore, cross-browser design continues to be a necessary aspect of Web development. Updated January 2, 2009 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/crossbrowser Copy

Cross-Platform

Cross-Platform Cross-platform software is software that is available for more than one computer platform. Each version of a cross-platform application may have slight differences in the user interface and feature set, but they are fundamentally the same program capable of opening the same files and performing the same functions. The opposite of a cross-platform app is a "native" app, developed exclusively for a single platform. Some cross-platform apps are available for both desktop and mobile platforms. In these cases, the mobile version of the app may have a limited feature set, but is compatible with the same documents and capable of most of its functions. For example, Microsoft Word is a cross-platform app with a full-featured desktop version available for Windows and macOS; it also offers a mobile version for iOS and Android and a web app that can run in a browser. Microsoft Word in Windows 11 and macOS Historically, each version of a cross-platform application required separate source code using each platform's native programming languages and APIs. However, modern cross-platform app frameworks and libraries help developers create apps using a single code base capable of running on multiple platforms. For example, the Electron app framework uses web technologies like HTML, CSS, and JavaScript to allow apps to run on desktop and mobile platforms. NOTE: Hardware peripherals compatible with multiple platforms, like USB mice and keyboards, may also be considered cross-platform. Updated October 30, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/crossplatform Copy

CRT

CRT Stands for "Cathode Ray Tube." CRT displays were a type of analog computer monitors and televisions commonly used up through the mid-2000s. A CRT display operates by firing electrons from the back of the vacuum tube towards an array of phosphor dots that coat the inside of the glass screen. These phosphor dots — arranged in stripes of red, green, and blue (RGB) — glow when hit by an electron to produce an image. Physically, CRT monitors were bulky and heavy compared to modern LCDs. The vacuum tube used in a CRT monitor required thick, lead-coated glass to hold up to the pressure; larger monitors required thicker glass, making them even heavier. A 17" CRT monitor was one of the most common sizes and usually weighed around 35 or 40 lbs (15-18 kg). The length required for the vacuum tube to operate meant that most CRT monitors were deeper than they were wide or tall, and the shape of the tube meant that they were very front-heavy. A ViewSonic CRT monitor Despite being completely replaced in the market by flat-panel LCDs, CRT monitors had some advantages over LCDs during the time they were both available. CRT monitors were able to reproduce colors more accurately than early LCDs. They did not have a native resolution, allowing you to switch between resolutions without any loss of image quality. They also produced an image faster with less input delay. Updated December 29, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/crt Copy

Cryptocurrency

Cryptocurrency A cryptocurrency is a software token that can be transferred securely and verifiably from one person to another. Cryptocurrency transactions are recorded on a public distributed database, called a blockchain, that uses cryptographic verification methods to authenticate each transaction. Cryptocurrencies are decentralized, not controlled by a central bank or other authority, and have no intrinsic value besides their scarcity. Thousands of separate cryptocurrencies were created during the cryptocurrency boom of the late 2010s and early 2020s, inspired by the success of early cryptocurrencies like Bitcoin and Ethereum. Each cryptocurrency has its own independent blockchain that records its entire history of transactions. Distributed groups of computers, often using specialized hardware and software, host the blockchain and process new transactions by appending data to it; those computers receive newly-created tokens as a reward for their work. Cryptocurrency owners store their tokens in a secure, encrypted application known as a wallet. A wallet includes a public address, similar to a bank account number, used to send and receive tokens. It also uses a cryptographic secret key to unlock and access the wallet. For convenience, many people store their cryptocurrency on exchanges, which maintain online wallets and provide services to exchange tokens for money or other tokens. A cryptocurrency blockchain processes transactions through either mining or staking. Mining involves groups of computers solving cryptographic puzzles while processing transactions and appending those transactions to the blockchain. Staking involves less computing power, requiring participants to lock up some of their tokens to prove their stake in the blockchain instead of solving puzzles. Bitcoin is the most popular mined cryptocurrency, and Ethereum is the most popular staked token. The Risks of Cryptocurrency Despite the name, cryptocurrencies do not generally function as currency. Cryptocurrencies have seen rapid swings in value from day to day that frequently change a token's purchasing power. Because of this volatility, few vendors accept Bitcoin directly, let alone smaller cryptocurrency tokens; most transactions first convert a cryptocurrency to a stable fiat currency like dollars or euros. It is much more common for enthusiasts to purchase tokens as a speculative investment, hoping that the token's value increases so that they may sell it later at a profit. Cryptocurrency's anonymity and potentially high value make people's wallets tempting targets for fraud. Both locally-stored wallets and those hosted on exchanges are common targets. In addition to direct intrusion attempts, phishing emails and other scams are frequently used to trick people into granting access to their tokens. Ransomware hackers attack computer systems and hold files for a cryptocurrency ransom. Unfortunately, once a victim's cryptocurrency is in the attacker's wallet and the blockchain has recorded the transaction, it cannot be recovered. Updated July 11, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cryptocurrency Copy

Cryptography

Cryptography Cryptography is the science of protecting information by transforming it into a secure format. This process, called encryption, has been used for centuries to prevent handwritten messages from being read by unintended recipients. Today, cryptography is used to protect digital data. It is a division of computer science that focuses on transforming data into formats that cannot be recognized by unauthorized users. An example of basic cryptography is a encrypted message in which letters are replaced with other characters. To decode the encrypted contents, you would need a grid or table that defines how the letters are transposed. For example, the translation grid below could be used to decode "1234125678906" as "techterms.com". 1t 6m 2e 7s 3c 8. 4h 9c 5r 0o The above table is also called a cipher. Ciphers can be simple translation codes, such as the example above, or complex algorithms. While simple codes sufficed for encoding handwritten notes, computers can easily break, or figure out, these types of codes. Because computers can process billions of calculations per second, they can even break complex algorithms in a matter of seconds. Therefore, modern cryptography involves developing encryption methods that are difficult for even supercomputers to break. Updated July 15, 2015 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cryptography Copy

CSS

CSS Stands for "Cascading Style Sheet." CSS is a style sheet language used for formatting content in HTML webpages. CSS style sheets can define the appearance and formatting of text, tables, and other elements separately from the content itself. Styles may be found within a webpage's HTML file or in a separate document referenced by multiple webpages. CSS helps web developers create a uniform look across an entire website. Instead of formatting the appearance of each table and block of text in a webpage's HTML code, a style is defined once in a CSS style sheet. Common HTML formatting tags, like , , and can have custom formatting defined in a CSS file; custom styles can also be created and applied to text, images, and tables. Once a style is defined, it can be used by any page that links to the CSS file. By separating a webpage's content from its formatting, CSS makes it easy to update styles across several pages at once. For example, if you want to increase the body text size from 10pt to 12pt across dozens of separate HTML pages, you only need to change the style once in the CSS file. The text size changes for every instance of that style on any webpage using that style sheet. Some web browsers include a reader mode that automatically changes text formatting from the webpage's default to a special built-in stylesheet optimized for easy reading. NOTE: The word "cascade" refers to the priority scheme used by CSS when multiple style rules overlap. User-defined CSS overrules styles applied directly to an HTML tag, which overrule any styles defined within the HTML document's header, which overrule any styles defined in an external CSS file. Updated March 7, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/css Copy

CSV

CSV Stands for "Comma-Separated Values." CSV is a standard way to store structured data in a plain text format. It is a common export option in desktop applications and some websites. Most spreadsheet programs can import data from a .CSV file. A list of comma-separated values represents a table. Each line in a CSV file is a row and the value between each comma is a column. The first row is often a table header containing labels for each column. Since the data in a CSV file represents a table, each line should have the same number of comma-separated values. CSV Format Since CSV files use the comma character "," to separate columns, values that contain commas must be handled as a special case. These fields are wrapped within double quotation marks. The first double quote signifies the beginning of the column data, and the last double quote marks the end. If the value contains a string with double quotes, these are replaced by two double quotes, or "". Below are some standard CSV formatting rules: Table data is represented using only plain text. The first line may or may not represent the table header. Rows are separted by line breaks (newline characters). Columns (fields) are separated by commas. All lines contain the same number of values. Fields that contain commas must begin and end with double quotes. Fields that contain line breaks must begin and end with double quotes (not all programs support values with line breaks). All other fields do not require double quotes. Double quotes within values are represented by two contiguous double quotes. Example CSV Data The following three lines represent a table with three rows and four columns, starting with a table header. ID,Website,URL,Description 1,TechTerms,https://techterms.com,"TechTerms, the Computer Dictionary" 2,Slangit,https://slangit.com,"Slangit, the ""Clean Slang"" Dictionary" The data above may be displayed in a table like this: IDWebsiteURLDescription 1TechTermshttps://techterms.comTechTerms, the Computer Dictionary 2Slangithttps://slangit.comSlangit, the "Clean Slang" Dictionary Using CSV Files A *.csv file can be opened, viewed, and edited in any text editor. However, because of the minimalistic nature of the CSV format, the data is often difficult to read. Therefore, it is best to view CSV files in a spreadsheet program like Microsoft Excel or Apple Numbers. These applications parse the comma-delimited data and display the values as a table within a spreadsheet. File extension: .CSV Updated July 18, 2020 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/csv Copy

CTP

CTP Stands for "Composite Theoretical Performance." CTP is used to measure the performance of computer processors. The values returned by CTP calculations are used for benchmarking purposes, which compare the performance of different processors. For example, Intel and AMD use CTP calculations to measure how many millions of theoretical operations per second (MTOPS) their processors can perform. An Intel Pentium M 770, which runs at 2.13 GHz, has a CTP of 7100 MTOPs, while an AMD Opteron 146, which runs at 2.0 GHz, has a CTP of 7168 MTOPS. As seen in the example above, faster processor speeds do not always result in a higher CTP. Other considerations, such as the processor's architecture and the speed of the frontside bus also affect the overall performance. CTP is useful for comparing different brands of processors, as well as comparing different models of processors made by the same company. With dual and quad processors becoming more prevalent, CTP is now also being used to measure the performance increase when multiple processors are used together. CTP also stands for "Computer to Plate." This is a process where printing plates are made without using costly film. Instead, the images are sent directly to the plate from the computer. Updated in 2006 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/ctp Copy

CTR

CTR Stands for "Click-Through Rate." CTR is a term used in online marketing that measures the percentage of times an ad gets clicked out of the times it appears. It is one measurement of the success of an advertisement in an online marketing campaign using a Pay Per Click (PPC) model. Online marketers track the CTR for a campaign as a whole, as well as for each individual ad and keyword. This allows advertisers to see which ads are most effective, then tailor their ads for the most effective messaging. Search engines that show advertisements often take an ad's CTR into account when determining its relevancy and overall quality score. An ad with a high quality score will appear more often and cost less on a Cost Per Click (CPC) basis, which incentivizes advertisers to continually improve the CTR of their ads. The number that is considered "good" for a CTR depends on the context of the ad. Most display and banner ads have a CTR of under 1%, social media ads are typically between 1-2%, and a good search keyword CTR is around 3-5%. CTR is also a metric tracked in email marketing, measuring the percentage of readers that click a link in an email. Other measurements for email marketing include the open rate (what percentage of people who received an email opened it) and the bounce rate (what percentage of emails sent were not delivered). Updated November 10, 2022 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/ctr Copy

CTV

CTV Stands for "Connected Television." CTV refers to any television that can connect to the Internet and stream video content. The term encompasses Smart TVs, which can connect directly to the Internet over Wi-Fi or ethernet, and any television that uses an Internet-connected streaming device like an Apple TV, Amazon FireTV stick, or Roku. A CTV can still connect to an antenna or set-top box to access traditional over-the-air, cable, and satellite TV but has additional options to access live and on-demand streaming video using built-in and third-party apps like Netflix, Hulu, and YouTube TV. Most televisions sold now (as of 2023) are CTVs. CTV is often used synonymously with another term, OTT (Over-The-Top). OTT refers to Internet-delivered video content accessible by Smart TVs, streaming devices, and other devices like desktop and laptop computers, tablets, and smartphones. As an increasing share of households drop cable and satellite TV services, they're accessing shows using OTT services on their CTVs instead. A Vizio D-Series Smart TV is an example of a Connected TV The advertising industry first introduced the term "CTV" to refer to a new advertising method in contrast to traditional linear broadcast television. Advertising to CTV devices adds several benefits to advertisers that were not possible before. For example, each video stream is delivered independently to each device, allowing the streamer to show different ads to each viewer targeted to their specific demographics and interests. They may also track a viewer's habits across devices using information like shared IP addresses and user accounts. Advertisers can also place ad buys programmatically and in real-time (instead of showing the same ad each time a show is streamed), which is more like how ads are placed on websites instead of traditional television. Updated December 12, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/ctv Copy

CUDA

CUDA Stands for "Compute Unified Device Architecture." CUDA is a parallel computing platform developed by NVIDIA and introduced in 2006. It enables software programs to perform calculations using both the CPU and GPU. By sharing the processing load with the GPU (instead of only using the CPU), CUDA-enabled programs can achieve significant increases in performance. CUDA is one of the most widely used GPGPU (General-Purpose computation on Graphics Processing Units) platforms. Unlike OpenCL, another popular GPGPU platform, CUDA is proprietary and only runs on NVIDIA graphics hardware. However, most CUDA-enabled video cards also support OpenCL, so programmers can choose to write code for either platform when developing applications for NVIDIA hardware. While CUDA only supports NVIDIA hardware, it can be used with several different programming languages. For example, NVIDIA provides APIs and compilers for C and C++, Fortran, and Python. The CUDA Toolkit, a development environment for C/C++ developers, is available for Windows, OS X, and Linux. Updated July 3, 2015 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cuda Copy

Cursor

Cursor A cursor is a movable icon on a computer screen that indicates where user input will take place. The two most common cursor types are the mouse cursor (which selects objects and clicks buttons) and the text cursor (which shows where the next typed character appears). Both cursors are controlled by the computer's mouse or trackpad, and the text cursor may also be controlled by the keyboard. In a computer with a graphical user interface, the mouse cursor is the primary way for you to interact with things on the screen. As you move the mouse across a surface (or your finger across a trackpad), the mouse cursor moves with it. You can issue commands by moving the mouse cursor onto an object and clicking the mouse button. The mouse cursor is typically an arrow, with its point indicating the exact spot that you'll interact with. However, the cursor's shape often changes to reflect a special interaction. For example, a mouse cursor changes to a hand icon when it hovers over a hyperlink on a webpage, or to a double-ended arrow when you can click and drag a window's border to resize it. Some applications, particular image editors, change the cursor's appearance when a tool is active to help you know what will happen when you click the mouse. For example, a crosshair icon indicates a rectangular selection, while a magnifying glass means you will zoom in when you click somewhere. The text cursor, also known as the insertion point, is a special cursor that appears in text fields and documents to show where newly typed characters will appear. It is typically a blinking vertical line, although sometimes it may be a horizontal line just below the text baseline. You can reposition the insertion point by clicking elsewhere in the text field, or by using the arrow keys to move it left, right, up, or down. In most applications, the mouse cursor disappears once you start typing to reduce distractions, but it will reappear once you move the mouse. Updated October 10, 2023 by Brian P. APA MLA Chicago HTML Link https://techterms.com/definition/cursor Copy

Cut

Cut Cut is a command that allows you to "cut out" a selection of text or other data and save it to the clipboard. It is similar to the Copy command, but instead of just copying the data to the clipboard, it removes the selected data at the same time. For example, if you highlight a sentence in a word processing program and select "Cut," the sentence is removed from the document and is added to the clipboard. Therefore, selecting "Cut" is an simple way to both copy and delete a selection in a single step. Objects that can be cut include text, images, audio and video segments, and other types of data. However, you may notice that some selections can only be copied and not cut. This is typically because the object is not editable and therefore can only be copied. If you cut a selection from a document, it can be pasted into another similar document. However, if you copy something else to the clipboard before pasting the selection, the cut data may be lost. Like the Copy and Paste commands, the Cut command is located in the Edit menu of most programs. The standard shortcut for "Cut" is Control-X in Windows and Command-X in Mac OS X. (If you're wondering why it isn't the "C" key, that shortcut is reserved for the Copy command.) Therefore, you can tell if a program supports the Cut command by clicking the Edit menu and looking for the Cut command. Updated February 13, 2009 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cut Copy

CVE

CVE Stands for "Common Vulnerabilities and Exposures." CVE is a system that provides unique identifiers for publicly known cybersecurity vulnerabilities. It operates like an extensive catalog, indexing security risks in software and assigning a distinct identifier to each, thereby facilitating standardized discussions, assessments, and management of these vulnerabilities across various platforms. The core principle of CVE is to establish a unified understanding of software vulnerabilities. When a new vulnerability is identified, it is recorded in the CVE database with a unique identifier in the format "CVE-YYYY-NNNNN", where "YYYY" represents the year of disclosure. This system, complemented by descriptive metadata and references, enables professionals in different fields—such as software development, system administration, and cybersecurity — to accurately and consistently reference each vulnerability. The CVE initiative is not standalone but part of a broader cybersecurity ecosystem. It is managed by the MITRE Corporation, with backing from the U.S. government. The integration of CVE identifiers into various cybersecurity tools and services aids in effective vulnerability management and remediation strategies. Additionally, the National Vulnerability Database (NVD) enhances the CVE system by providing extended metadata, including risk assessments and impact evaluations for each listed vulnerability. CVE's role is critical in the contemporary digital landscape. It provides a common language for diverse entities, from IT departments implementing system patches to software vendors resolving product bugs. Awareness and understanding of relevant CVEs are essential for ensuring that the software and systems in use are protected against known vulnerabilities, thereby promoting a more secure digital environment for individuals and organizations alike. Updated January 22, 2024 by Nils-Henrik G. Reviewed by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cve Copy

Cyberbullying

Cyberbullying There are bullies and then there are cyberbullies. While bullying typically happens at school or work, cyberbullying takes place over cyberspace. This includes both Internet and cell phone communication. Like physical bullying, cyberbullying is aimed at younger people, such as children and teenagers. It may involve harassing, threatening, embarrassing, or humiliating young people online. Cyberbullying can take many forms. The following are just a few examples: Making fun of another user in an Internet chat room. Harassing a user over an instant messaging session. Posting derogatory messages on a user's Facebook or MySpace page. Circulating false rumors about someone on social networking websites. Publishing lewd comments about another person on a personal blog. Posting unflattering pictures of another user on the Web. Spamming another user with unwanted e-mail messages. Sending threatening or provocative e-mails. Repeatedly calling another person's cell phone. Sending unsolicited text messages to another user. Cyberbullying may seem humorous to some people, but it is a serious matter. Kids who are bullied online often feel hurt and rejected by their peers. This can lead to low self esteem and depression. Therefore, cyberbullying should not be tolerated and should be reported to authorities. NOTE: Technically, cyberbullying takes place between two young people. When adults are involved, it may be called cyber-harassment or cyberstalking. Updated September 15, 2009 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cyberbullying Copy

Cybercrime

Cybercrime Cybercrime is criminal activity done using computers and the Internet. This includes anything from downloading illegal music files to stealing millions of dollars from online bank accounts. Cybercrime also includes non-monetary offenses, such as creating and distributing viruses on other computers or posting confidential business information on the Internet. Perhaps the most prominent form of cybercrime is identity theft, in which criminals use the Internet to steal personal information from other users. Two of the most common ways this is done is through phishing and pharming. Both of these methods lure users to fake websites (that appear to be legitimate), where they are asked to enter personal information. This includes login information, such as usernames and passwords, phone numbers, addresses, credit card numbers, bank account numbers, and other information criminals can use to "steal" another person's identity. For this reason, it is smart to always check the URL or Web address of a site to make sure it is legitimate before entering your personal information. Because cybercrime covers such a broad scope of criminal activity, the examples above are only a few of the thousands of crimes that are considered cybercrimes. While computers and the Internet have made our lives easier in many ways, it is unfortunate that people also use these technologies to take advantage of others. Therefore, it is smart to protect yourself by using antivirus and spyware blocking software and being careful where you enter your personal information. Updated in 2006 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cybercrime Copy

Cyberspace

Cyberspace "Cyberspace" is the digital world created by computers and other network-connected devices. It encompasses everything from local data storage to global communication over the Internet. Whether you're viewing photos on your computer, sending an email, or browsing the web, you are operating within cyberspace. Origin of Cyberspace The term "Cyberspace" was popularized by science fiction author William Gibson in his 1984 novel Neuromancer. Gibson depicted cyberspace as: "a consensual hallucination experienced daily by billions of legitimate operators, in every nation, by children being taught mathematical concepts... A graphical representation of data abstracted from the banks of every computer in the human system. Unthinkable complexity. Lines of light ranged in the non-space of the mind, clusters and constellations of data." A visual depiction of cyberspace Though a novel concept at the time, cyberspace is now an integral part of everyday life. In fact, it is so ubiquitous that people rarely use the term anymore. Instead, people use terms like social media, e-commerce, and the metaverse to describe more specific aspects of cyberspace. Updated July 31, 2024 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cyberspace Copy

Cybersquatter

Cybersquatter In the early days of the United States, pioneers traveled west and claimed federal land as their own. These people were called "squatters," since they claimed rights to the land simply by occupying it. In the mid-1800s, during the California gold rush, squatters became especially prominent and settled land throughout the west coast. In the early 1990s, a new gold rush began, but this time the rush was for domain names, rather than gold. Many early Internet users saw the potential value of prominent domain names and began to register as many domains as they could. Over the course of a few years, nearly all common "dot coms" were registered. Many of these domain names were registered for investment purposes, rather than being used for legitimate websites. This practice soon became known as "cybersquatting." Cybersquatters may own anywhere from a single domain to a few thousand domain names. These "domainers," as they are also called, typically register domain names that contain popular words and phrases. High profile domain names may generate traffic through manual "type-ins" or may simply be attractive to potential buyers. Some domainers, called "typosquatters," register domain names that are similar to well-known websites, but contain typos. The goal of these domains is to generate traffic through mistyped URLs. Generally, cybersquatters profit from their domain names by one of two ways: 1) generating advertising clicks on parked pages (single-page websites), or 2) selling the domains at a significant premium to those interested in buying them. While some cybersquatters have made huge profits by selling high-interest domain names, others have been forced to give up domains to the rightful owners. The Anticybersquatting Consumer Protection Act (ACPA) was passed in 1999, which gives owners of trademarked or registered names legal rights to a related domain name. In general terms, the law states that users cannot register a domain name that is the same or similar to the name of a known entity. This prevents cybersquatters from extorting money from businesses or individuals by obtaining a specific domain name. If a dispute over a domain name arises, the two parties may bring the case through a legal proceeding. However, since this is a time-consuming process, ICANN has developed the Uniform Domain Name Dispute Resolution Policy (UDRP), which givens trademark owners a simple means to retrieve domain names from cybersquatters. While cybersquatters still exist and remain prominent today, the rightful owners of certain names now have an easier (and much less expensive) way of getting the domain names they deserve. Updated December 23, 2010 by Per C. APA MLA Chicago HTML Link https://techterms.com/definition/cybersquatter Copy