Glossary terms provided by TechTerms.com.
| Word | Description |
| C/C++ | C is a high-level programming language that was developed in the mid-1970s. It was originally used for writing Unix programs, but is now used to write applications for nearly every available platform. Compared to most previous languages, C is easier to read, more flexible (can be used for a wide variety of purposes), and more efficient at using memory. C++, pronounced "C plus plus," is a programming language that was built off the C language. The syntax of C++ is nearly identical to C, but it has object-oriented features, which allow the programmer to create objects within the code. This makes programming easier, more efficient, and some would even say, more fun. Because of the power and flexibility of the language, most software programs today are written in C++. |
| CA | Certificate Authority. |
| Cab file (cabinet file) | A compressed file with the extension .cab. Cabinet files are used to store installation files for Microsoft applications, most commonly Windows 9x operating systems and Internet Explorer. Cab files were initially designed to fit large installations onto a group of 1.44 MB floppy disks. |
| Cabinet file (cab file) | A compressed file with the extension .cab. Cabinet files are used to store installation files for Microsoft applications, most commonly Windows 9x operating systems and Internet Explorer. Cab files were initially designed to fit large installations onto a group of 1.44 MB floppy disks. |
| Cable Modem | A modem for use with cable systems. Offers much higher data rates than conventional analogue modems. Where a cable modem has LEDs on the front, these are typically one or more of: LED Short for Description PWR Power Power on indicator. USB USB Indicates activity on USB connection. ENET Ethernet Indicates activity on Ethernet connection. U/S Up Stream D/S Down Stream SYNC RDY Ready Indicates that the modem is ready for normal use. Off indicates that it is performing its self test or that there is a fault. |
| Cable Select (CSEL) | This is basically Plug-and-Play ATA. You plug in your ATA/IDE hard drives, set them to CSEL (Cable Select), and they determine whether they are master or slave automatically, saving you from manual configuration. |
| Cache | A memory store used to hold a copy of data, to improve the apparent speed of computer components including processors, disk drives, graphics cards etc. Where data is available in the cache it is retrieved from the cache instead of the device. For example most processors contains a memory cache with faster access than main memory, data that is available in the cache is therefore available to the processor much faster than it would be if it had to go to main memory to retrieve the data. Information available in a disk cache can be returned almost instantly whilst data that is not available in the cache would need to be read from the physical disk and this would be magnitudes slower. cf buffer. It is common for a cache to use a LRU algorithm to determine which item to remove from the cache when new data needs to be loaded into the cache. However there are other algorithms that some caches use, for example discarding the oldest item or an algorithm based on the frequency of use. |
| Cache Cramming | Cache Cramming is the technique of tricking a browser to run cached Java code from the local disk, instead of the internet zone, so it runs with less restrictive permissions. |
| Cache memory | Generally a small chunk of fast memory that sits between either 1) a smaller, faster chunk of memory and a bigger, slower chunk of memory, or 2) a microprocessor and a bigger, slower chunk of memory. The purpose of cache memory is to provide a bridge from something that’s comparatively very fast to something that’s comparatively slow. Most microprocessors have built-in cache memory that holds some of the information from main memory. When the processor needs the information it takes it from the speedy cache instead of the slower main memory. Cache memory GREATLY increases the speed of a computer by storing data that is most often accessed. |
| Cache Poisoning | Malicious or misleading data from a remote name server is saved [cached] by another name server. Typically used with DNS cache poisoning attacks. |
| CACHED LINK | In search results from Google, Yahoo! Search, and some other search engines, there is usually a Cached link which allows you to view the version of a page that the search engine has stored in its database. The live page on the web might differ from this cached copy, because the cached copy dates from whenever the search engine's spider last visited the page and detected modified content. Use the cached link to see when a page was last crawled and, in Google, where your terms are and why you got a page when all of your search terms are not in it. |
| Caching | To make us of a cache, for improved performance (i.e. typically to increase apparent speed). |
| CAD | Stands for "Computer-Aided Design." Also known by engineers and architects as the best invention of all time. Today, CAD software is used for nearly all three-dimensional designing. Designers can turn an object into an electronic representation more quickly and accurately than by diagraming it with a pencil and paper. Better yet, objects created with CAD software can be moved, resized, and rotated instantly. With a pencil and paper, you can only erase so much before it starts to smudge. |
| CAL | 1. Client Access License. 2. Computer Aided Learning or Computer Assisted Learning. |
| Camera RAW | Most digital cameras process and compress the pictures you take immediately after capturing the image. This can be helpful, as it keeps the file sizes low (using JPEG compression) and takes care of color correction, including white-balance, tint, and exposure, so you don't have to. However, some people, such as professional photographers, prefer to have more control over how each image is processed. Therefore, many high-end cameras have the ability to shoot in RAW mode. This mode does not compress the images at all and leaves them completely unprocessed. Because Camera RAW files are uncompressed, they take up more space than typical JPEG images. In fact, RAW files often require 2 to 3 times more space for each image captured. So, you'll want to have an extra-large memory card in your camera if you plan on shooting in RAW mode. But since RAW photos are not compressed, you maintain the full quality of each image. This can make a noticeable difference when printing images, especially for large prints. Camera RAW files are also unprocessed, meaning all the photo processing is done on the computer. It is like taking a film negative to a dark room to be developed. The RAW file is the negative and the computer serves as the dark room. With a RAW file, you have complete control over the temperature adjustments (for white-balance), tint, hue, and exposure. However, since Camera RAW files are not typical images, most image-viewing programs will not open them. Therefore, most camera companies include Camera RAW editing software with their high-end cameras. These programs allow you to open RAW files, do the necessary processing, and save them in common image formats such as bitmap, TIFF, and JPEG. While shooting in Camera RAW mode offers a lot of control over your photos, it takes additional software and extra time to open and edit each picture you take. For most casual photography, using the camera's built-in processing is the most suitable option. |
| Capacitor | An electronic component that stores up an electrical charge to a certain level and then releases it. A capacitor stores energy between two conducting plates separated by an insulator, or dialectric. Capacitance, or the amount of current that is stored, is measured in farads. You may notice large looking electronic cylinders on your motherboard. These are capacitors, and they are used to provide clean power to your processor. You’ll also find larger capacitors in your power supply. CRT televisions and monitors contain many capacitors, that’s why you are warned against opening up a CRT device or power supply even when it is off, as there may still be electrical energy in the capacitors. |
| Capacity Planning | The operation of calculating how many resources a physical server will need for hosting a certain amount of virtual machines. It's a critical task to be achieved at very beginning of any virtualization project. |
| caps | Upper-case letters. When you press the Caps Lock key on your keyboard, it makes everything you type upper-case. In the early days of computing, many computers had no way of representing lower-case and upper-case letters, but all computers today have that capability. You should avoid typing a message in all caps, because it makes the text harder to read. |
| Captcha | A captcha is a challenge-response test that determines whether a user is human or an automated bot. A typical captcha includes an image of distorted text and a form field for the user to enter the text. Captchas are commonly found at the end of website forms, and must be filled out in order for the form to be submitted. By requiring users to decipher and enter the captcha text, webmasters can prevent automated programs from sending spam or other unwanted data through online forms. |
| Capture | The process of copying digital information from the web to a repository for collection or archive purposes. |
| Cardbus | The 32-bit PCMCIA card slot and cards that can work in this slot. Standard PCMCIA, or PC Card, slots were originally 16-bit slots. This caused problems when 100Mbit network cards and fast SCSI cards were used and throughput would not go high enough because the 16-bit slots were too slow. |
| CAS | Code Access Security. The security mechanism used in the Microsoft CLR. CAS works by assigning trust levels (i.e. permissions) to software code (rather than the traditional model of assigning permissions by user). |
| CAT5 | Category 5 Ethernet network cabling. The CAT5 standard allows for transmission speeds of up to 100mbps over distances of up to 100m. cf CAT5E, CAT6. |
| CAT5E | Category 5 Ethernet network cabling. (CAT 5 Enhanced.) The CAT5E standard allows for transmission speeds of up to 1000mbps (giga-bit Ethernet). There is little real difference in the cabling standards between CAT5 and CAT5E, the standards for CAT5E being only a little more stringent over CAT5. CAT6 gives a more stringent standard for 1000mbps Ethernet network cabling. |
| CAT6 | Category 6 Ethernet network cabling. The CAT6 standard allows for transmission speeds of up to 1000mbps (giga-bit Ethernet). CAT6 is similar to CAT5E, but to a higher standard. cf CAT5E. |
| CC | 1. Carbon Copy. An e-mail or memo that is CC'd to someone is copied to that person, with all the recipients of the e-mail or memo seeing the person named on the distribution list. cf BCC. 2. Continuity Check. 3. C Compiler. cc is the name of a C language compiler available on most Unix systems. 4. Credit Card. Any credit card. 5. Conditional Compilation. A software language construct which allows blocks of code to be included or excluded at compile time. Software which is conditionally compiled out, will not then exist in the resultant library or executable. 6. Conditional Comments. Comments embedded in HTML that allow sections of the HTML to be included or excluded depending on a specified condition. Supported by Internet Explorer (IE), but not commonly supported by other browsers. 7. Cubit Centimeter. Also written as cm3. The SI-unit of volume, corresponds to the volume of a cube measuring 1cm on each side (i.e. the volume enclosed by the cube measuring 1cm x 1cm x 1cm). 1cc of water is also defined as equal to 1 gram of water. 8. Cubic Capacity. Term used when describing the volume of a cylinder in an engine (for example in a car engine). It is the available volume of the cylinder when the piston is pushed fully out. Also known as engine displacement. It should be appreciated that cubic capacity is a term and does not imply units. Cubic capacity is typically (but not always) expressed in cubic inches or cubic centimeters. 9. Closed Caption (or Closed Captioning). A system for encoding a text version of the dialog contained on a TV, film or computer presentation allowing the captions to be displayed for those who are hard of hearing. Closed Caption is encoded with the video. Video or DVD players which support closed caption allow the closed captions to be displayed as subtitles. In most contexts "Closed Caption" means the same as "Subtitles". |
| Cc (Carbon Copy) | Stands for "Carbon Copy." The term comes from carbon copying, in which a piece of carbon paper copies writing from one paper to another (often used when filling out forms). However, the term is now commonly used in reference to e-mail. When you send an e-mail message, you typically type the recipient's address in the "To:" field. If you want to send the message to one or more other recipients, you can use the "Cc:" field to add additional addresses. This will send the e-mail to the address in the "To:" field and to each address listed in the "Cc:" field as well. The "Cc:" option is often used in business communications when a message is intended for one person, but is relevant to other people as well. For example, a retail employee may e-mail another employee saying he can work for her on a certain day. He might include his manager's and assistant manager's e-mail addresses in the "Cc:" field to let them know he is taking the work shift. Similarly, a team member working on a product design may e-mail his boss with the latest design revisions and may "Cc:" the other members of his team to let them know the e-mail has been sent. "CCing" (yes, it can also be used as a verb) is a quick way to let other people in on your e-mail communications. It is efficient because you don't have to send separate messages to each individual address. However, remember that When you Cc an e-mail, all the recipients can see the other addresses the message was sent to. If you want to hide the additional addresses, use Blind Carbon Copy (Bcc) instead. |
| CCD | Charge Coupled Device. The image recording device inside a digital camera. |
| CCTV | Closed Circuit Television. A television system where the camera and video monitor (or TV) are connected directly via cables and the camera signal is not broadcast for others to pick-up. CCTV is typically used for video monitoring and surveillance and used as part of a security system. |
| CD-R | CD-Recordable. A recordable (normally write once) compact disc (CD), cf CD-RW. |
| CD-RW | CD-Readable-Writable. A compact disc (CD) which can be recorded to and overwritten many times. cf CD-R. |
| CDP Server | CDP Server 2.0 is a near continuous backup application for Windows and Linux computers, produced by R1Soft. CDP Server 2.0 provides user scheduled near continuous disk-based online backups for one or more Windows or Linux servers. Each time a user scheduled backup is performed, Delta encoding deltas are transmitted to a backup repository effectively creating a virtual Disk image. CDP Server can restore previously captured disk images to another disk effectively replicating the structure and contents to a new disk. Individual files inside of a disk image can be restored to their original location or an alternate computer. As of November 2008 the application is reported to be used on over 90,000 Linux servers.[4] Operation The first time the CDP Server application is used on a new backup target computer it creates a replica of all data and structure on disk to a disk-based backup repository. After this initial replica the CDP Server application uses a volume filter device driver to track block level deltas between scheduled synchronizations. The next scheduled backup operation involves creating a point in time snapshot and reading the deltas as tracked by the volume filter device driver. Synchronizations can be scheduled as frequently as every 15 minutes for an entire server.[4] CDP Server is known for its simple web based interface.[5] Microsoft Volume Shadow Copy Service is used on Windows to take a point in time snapshot. On Linux a proprietary Linux kernel module is used. [edit]Supported File Systems File systems supported by software:[6] NTFS ext2 ext3 ReiserFS Linux Swap Limitations CDP Server 2.0 can only backup disks or volumes less than or equal to 8TB in size.[7] Each disk is required to contain a valid partition table.[8] Bare-metal system restore can only be performed to the same hardware. |
| cell | The box in a spreadsheet that occurs at each intersection of a row and column. You can use a cell to store text, number, formulas, or dates. |
| CentOS | CentOS is a community-supported, free and open source operating system based on Red Hat Enterprise Linux. It exists to provide a free enterprise class computing platform and strives to maintain 100% binary compatibility with its upstream distribution.[1] CentOS stands for Community ENTerprise Operating System. Structure Red Hat Enterprise Linux is available only through a paid subscription service that provides access to software updates and varying levels of technical support. The product is largely composed of software packages distributed under open source licenses, and the source code for those packages is made public by Red Hat. CentOS developers use Red Hat's source code to create a final product very similar to Red Hat Enterprise Linux. Red Hat's branding and logos are changed because Red Hat does not allow them to be redistributed.[2] CentOS is available free of charge. Technical support is primarily provided by the community via official mailing lists, web forums, and chat rooms. The project is not affiliated with Red Hat and thus receives no financial or logistical support from the company; instead, the CentOS Project relies on donations from users and organizational sponsors. |
| Certificate | An SSL certificate, or secure certificate, is a file installed on a secure Web server that identifies a website. This digital certificate establishes the identity and authenticity of the company or merchant so that online shoppers can trust that the website is secure and reliable. In order to verify that these sites are legitimate (they are who they say they are), the companies and their websites are verified by a third party, such as Verisign or Thawte. Once the verification company establishes the legitimacy of an organization and the associated website, they will issue an SSL certificate (for the small fee of a few hundred dollars). This digital certificate is installed on the Web server and will be viewable when a user enters a secure area of the website. You can tell you are visiting a secure page when the URL starts with "https." To view the certificate, click the lock icon near one of the edges of your browser window. Because digital certificates verify a company's current status, they do not last forever. SSL certificates typically expire every one to three years. If the certificate is not renewed in time, you may see an alert box pop up that says "This website's certificate has expired." This error has nothing to do with you or your computer, but is displayed because the Web server you connected to has not renewed its SSL certificate. While this does not necessarily mean the site is fraudulent, it does show that the site is less than professional. |
| Certificate-Based Authentication | Certificate-Based Authentication is the use of SSL and certificates to authenticate and encrypt HTTP traffic. |
| cf | is an abbreviation for the Latin word confer, meaning "compare" or "consult", and is hence used to refer to other material or ideas which may provide different information or arguments. It is mainly used in scholarly or educated contexts, such as in academic (mainly humanities) or legal texts. |
| CGI | Common Gateway Interface. Interface standard allowing programs to interface to web servers. CGI programs can be written in any compilable language. CGI programs are executed on the server, normally in response to some input from a web page. See also: ASP. |
| cgi-bin | The most common name of a directory on a web server in which CGIprograms are stored. |
| Challenge-Handshake Authentication Protocol (CHAP) | The Challenge-Handshake Authentication Protocol uses a challenge/response authentication mechanism where the response varies every challenge to prevent replay attacks. |
| Channel | The group of resellers that supply most companies with software, hardware, and support. The channel is a force to be reckoned with, and it competes directly against, and works with, companies like Dell and IBM. A channel can also be a content container, like a television channel. |
| CHAP | 1. Challenge Handshake Authentication Protocol. An authentication protocol. The server sends the client a (one time) key to be used to encrypt a username and password combination. Subsequently the server may reconfirm the connection by repeating the process - this is to protect against an attacker substituting a different client once the connection has been made. 2. In general speech: A man or boy. |
| Character | A character is any letter, number, space, punctuation mark, or symbol that can be typed on a computer. The word "computer," for example, consists of eight characters. The phrase "Hi there." takes up nine characters. Each character requires one byte of space, so "computer" takes up 8 bytes. The list of characters that can be typed is defined by the ASCII and extended ASCII set. Some of the symbols available are pretty strange and may even make you say, "That's quite a character!" |
| Chassis | Pronounced “chassy,” this is the frame or case which holds your computer components. |
| Checkpoint | At a database checkpoint the database flushes out data not yet written to disk. |
| Checksum | A checksum is a calculated sum used to check the integrity of a file. It can be generated from one of many algorithms, such as cyclic redundancy check (CRC) or a cryptographic hash function. When the checksums of two sets of data match, it indicates that the data sets are identical. Therefore, checksums are a quick and easy way to verify disk images, burned discs, and other types of files. |
| Chip | Technically speaking, a computer chip is a piece of silicon with an electonic 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. |
| Chipset | chipset describes the architecture of an integrated circuit. This includes the layout of the circuitry, the components used within the circuit, and the functionality of the circuit board. For example, the chipset of a modem card is much much different than the chipset of a computer's CPU. Processors themselves also have different chipsets. For example, A PowerPC processor, which uses RISC architecture, will have a much different chipset than an Intel processor that uses CISC technology. Even a Pentium II and Pentium III have slightly different chipsets, though they are both made by Intel. Regardless of what chipset a circuit uses, the important thing is that it works with other components inside the computer. Therefore, whenever you upgrade your computer's hardware, make sure you buy components that are compatible with the chipsets in your machine. |
| chkdsk (check disk) | A Microsoft program that checks your hard drive for logical errors as opposed to physical defects. This program is supported in DOS and all versions of Windows. Windows NT/2000/XP uses it as its main disk checking program. DOS and Windows replaced this program with the friendlier scandisk.exe, but chkdsk.exe is still available and is still the main disk checking program for NTFS partitions. |
| Chmod | Abbreviation for "Change Mode". Chmod is a command line utility available on both Unix systems which allows the file permissions of files to be changed. (The closest equivalent to Chmod on Windows is the command line utility chmod, but the permissions settings are very different.) For full details on how to use chmod consult the Unix man pages. The following is intended as a summary: The syntax for using chmod is as follows: chmod switches mode file Where switches can be any of: -R --recursive Recursive. Change the mode of the directories as well as the files. -P --physical --nofollow Do not follow symbolic links. -f --quiet --silent Do not display any messages. -h --symlink For symbolic links, change the mode of the link -v --verbose Show all files and changes. The mode indicates file permissions for the owner, group and all users. These can either be expressed using a number or symbolically. As a number, it appears as a three digit octal number. The first digit specifying the owner permissions, the second group permissions and the final digit all user (i.e. world) permissions. Where each digit is made up of any combination of the following binary flags: Flag Meaning 4 Allow read 2 Allow write 1 Allow execute (for scripts and programs) Thus the 8 possible values for each digit are: Digit Meaning 0 Deny all 1 Execute only (no read or write permissions) 2 Write only. 3 Write or execute (but not read) 4 Read only. 5 Read and execute. 6 Read and write. 7 Allow all. So to grant the owner full access, members of the group read and execute and all other users execute only, would be: chmod 751 file |
| CIDR | Classless Inter-Domain Routing. An addressing scheme for IP addresses, providing greater flexibility in defining the domain than was possible with simple class A, B and C addressing. |
| CIFS | Common Internet File System. File sharing protocol based originally on SMB (Server Message Block). |
| Cipher | A cryptographic algorithm for encryption and decryption. |
| Ciphertext | Ciphertext is the encrypted form of the message being sent. |
| Circuit breaker | A device that interrupts the flow of electricity if an excessive level of current is detected. It’s a better design than the fuse, as it can just be reset (instead of replaced) to turn the electrical flow back on. |
| Circuit Switched Network | A circuit switched network is where a single continuous physical circuit connected two endpoints where the route was immutable once set up. |
| CISCO | Cisco Systems is a leading network solutions provider. The term CISCO is normally used to refer to network equipment produced by Cisco or one of their certification schemes (see also CCNA and CCNP). |
| Class A IP | A group of IP addresses where the first number remains the same, and the last three can vary. It could be represented by w.x.y.z, where the x, y, and z can be any number from 0-255, and the w represents the first static part of the IP address (e.g., 10.x.y.z). Thus, the number of possible combinations within the Class A address are 256*256*256 = 16,777,216. Of course, some of the addresses, like those ending in .0 and .255, are not used, so the actual number of usable addresses in a Class A is somewhat less than that. The subnet mask of a class A IP address is 255.0.0.0. Thus, only the last three digits of the IP address are used to determine where traffic gets routed within the Class A. There are 254 class A groups in existence. |
| Class B IP | A group of IP addresses where the first two numbers remain the same and the last two can vary. It could be represented by w.x.y.z, where the y and z can be any number from 0-255, and the w and x represent the first static part of the IP address (e.g., 10.251.y.z). Thus, the number of possible combinations within the Class B address are 256*256 = 65,536. Of course, some of the addresses, like those ending in .0 and .255, are not used, so the actual number of usable addresses in a Class B is somewhat less than that. The subnet mask of a class B IP address is 255.255.0.0. Thus, only the last two digits of the IP address are used to determine where traffic gets routed within the Class B. There are about 65,000 class B groups in existence. |
| Class C IP | A group of IP addresses where the first three numbers remain the same and the last one can vary. It could be represented by w.x.y.z, where the z can be any number from 0-255, and the w, x, and y represent the first static part of the IP address (e.g., 10.251.37.z). Thus, the number of possible combinations is 256. Of course, some of the addresses, like those ending in .0 and .255, are not used, so the actual number of usable addresses in a Class C is 254. The subnet mask of a class C IP address is 255.255.255.0. Thus, only the last digit of the IP address is used to determine where traffic gets routed within the Class C. There are about 16.7 million class C groups in existence. |
| CLEC (Competitive Local Exchange Carrier) | The Telecommunications Act of 1996 sought to create this type of service company that would offer local calling, long distance, international calling, and Internet access. The CLECs would compete with the incumbent local exchange carrier (then Bell Atlantic) by leasing their local loops and creating their own on which to sell services. |
| CLI | 1. Call Level Interface. An interface with a computer requiring solely textual input and providing only textual output. 2. Command Line Interface. cf GUI. 3. Caller Line Identification. Allows the recipient of a telephone call to see the caller's phone number before answering the call. |
| Click Fraud | Click Fraud The repetitive clicking on ads on a website in order to generate revenue for the website. More accurately known as pay-per-click fraud, for more details see Pay-Per-Click Fraud. |
| Client | A software program that is used to contact and obtain data from a Server software program on another computer, often across a great distance. EachClient program is designed to work with one or more specific kinds of Server programs, and each Server requires a specific kind of Client. A Web Browser is a specific kind of Client. |
| Client/Server | Client server technology came about when computers began to cost less. Mainframes are very expensive, and didn’t give users much personal freedom. The client/server model promised to change that scenario, and it’s much more popular today. Basically, a client computer with its own memory and hard drive communicates with a server whenever it needs data from the server. The client can run by itself without the server and communicate with different servers as it needs to. |
| Clipboard | The clipboard is a section of RAM where your computer stores copied data. This can be a selection of text, an image, a file, or other type of data. It is placed in the clipboard whenever you use the "Copy" command, which is located in the Edit menu of most programs. Data from the clipboard can be pasted into a document or program using the "Paste" command, which is also located in most programs' Edit menu. For example, an image copied to the clipboard from your photo album may be pasted into an image editing program such as Photoshop. A Web address can be copied to the clipboard from an e-mail and pasted into your Web browser's address field. Some programs allow you to see what data is stored in the clipboard. For example, the Finder in Mac OS X allows you to choose "Show Clipboard" from the Edit menu. When you copy data to the clipboard, whatever data was already stored in the clipboard is typically replaced by the new data. Because the clipboard data is stored in RAM, it is also deleted when your computer is shut down or restarted. |
| Clock Cycle | Think of a clock cycle as one tick of the second hand (but generally at a much higher speed). Computer clocks run voltage through a tiny crystal that oscillates at a predictable speed to give a meaningful timing method to the computer. One clock cycle doesn’t necessarily mean that the processor does one operation. Today’s high-end processors often complete more than one operation per clock cycle, and other times, in the worst cases, it will take several clock cycles to complete one operation. |
| Clock Speed | Clock speed is the rate at which a processor can complete a processing cycle. It is typically measured in megahertz or gigahertz. One megahertz is equal to one million cycles per second, while one gigahertz equals one billion cycles per second. This means a 1.8 GHz processor has twice the clock speed of a 900 MHz processor. However, it is important to note that a 1.8 GHz CPU is not necessarily twice as fast as a 900 MHz CPU. This is because different processors often use different architectures. For example, one processor may require more clock cycles to complete a multiplication instruction than another processor. If the 1.8 GHz CPU can complete a multiplication instruction in 4 cycles, while the 900 MHz CPU takes 7 cycles, the 1.8 GHz processor will be more than twice as fast as the 900 MHz processor. Conversely, if the 1.8 GHz processor takes more cycles to perform the instruction, it will be less than 2x as fast as the 900 MHz processor. Other factors, such as a computer's bus speed, cache size, speed of the RAM, and hard drive speed also contribute to the overall performance of the machine. Therefore, while the processor's clock speed is a significant indicator of how fast a computer is, it is not the only factor that matters. |
| Clone | What do sheep, droids, and computers all have in common? They can all be cloned! Of the three, computer clones are by far the most common. The term "clone" arose in the mid-1980s to describe DOS or Windows-based computers made by companies other than IBM. The machines were often referred to as "IBM clones," or "IBM compatible" computers. They were called clones because the computers functioned exactly the same way as the ones made by IBM. They used similar hardware and ran the same software. PC clones are still around today. In fact there are dozens more manufacturers of Windows-based computers now than there were in the 1980s. Companies like Dell, Gateway, HP, Compaq, and Sony all make Windows-based computers, as well as many other manufacturers. Today, the term "PC," which technically stands for "Personal Computer," is often used to refer to IBM clones. Macintosh clones were made for a few years in the late 1990s, but Apple forced the end of their production by making the Macintosh operating system only run on the Apple-branded machines. "Clone" can also be used to refer to software that serves the same purpose as another more mainstream software program. It can also refer to electronic devices other than computers that are similar to other electronics. |
| Cloud computing | Cloud computing is Internet- ("cloud-") based development and use of computer technology ("computing").[1] In concept, it is a paradigm shift whereby details are abstracted from the users who no longer have need of, expertise in, or control over the technology infrastructure "in the cloud" that supports them.[2] Cloud computing describes a new supplement, consumption and delivery model for IT services based on the Internet, and it typically involves the provision of dynamically scalable and often virtualized resources as a service over the Internet.[3][4] The term cloud is used as a metaphor for the Internet, based on the cloud drawing used to depict the Internet in computer network diagrams as an abstraction of the underlying infrastructure it represents.[5] Typical cloud computing providers deliver common business applications online which are accessed from a web browser, while the software and data are stored on servers. These applications are broadly divided into the following categories that emphasize the notion of "Everything-as-a-Service"[6]: Software as a Service (SaaS), Utility Computing, Web Services, Platform as a Service (PaaS), Managed Service Providers (MSP), Service Commerce, and Internet Integration. |
| CLR | Common Language Runtime. The CLR executes .NET code and is similar in concept to the Java Virtual Machine. |
| Cluster | Cluster 1. In general usage a cluster is a number of similar things which are grouped together. For example a cluster of stars or a set of events grouped by date and/or geographic location. 2. A number of linked computers, which work together and can appear and be treated in some respects as though they were a single computer. Also known as clustering. 3. The smallest amount of space that is allocated on a disk for a file or folder. The cluster size is fixed when a disk is formatted, and may vary between systems as a function of disk size, operating system, file system type (e.g. FAT or NTFS). cf cluster size. |
| Cluster Size | The smallest amount of space that a file can occupy on a disk. Storage on a hard or floppy disk is made up of disk sectors, a cluster is a set of one or more adjacent disk sectors. The operating system allocates disk storage by allocating one or more whole clusters, so the space occupied by a file is always an integral multiple of the cluster size. |
| Clustering | Connecting many computers together so that they appear (for many purposes) as a single machine. Clustering computers together in this way is normally done to provide greater reliability and performance. It is also known as a (computer) cluster. |
| CMOS | Stands for "Complementary Metal Oxide Semiconductor." This technology is typically used in making transistors. The "complementary" part of the term unfortunately does not mean these semiconductors are free. Instead, it refers to how they produce either a positive or negative charge. Because CMOS-based transistors only use one charge at a time, they run efficiently, using up very little power. This is because the charges can stay in one state for a long period of time, allowing the transistor to use little or no power except when needed. Because of their wonderful efficiency, processors that use CMOS-based transistors can run at extremely high speeds without getting too hot and going up in flames. You may also find CMOS memory in your computer, which holds the date and time and other basic system settings. The low power consumption of CMOS allows the memory to be powered by a simple Lithium battery for many years. |
| CMS | 1. Content Management System. An application designed to help manage the content of a website. Typically a CMS allows multiple people to work on the content of a website without them needing to know HTML. A CMS system will provide the ability to edit and update pages as well as adding new pages and adding pictures. A CMS system may also provide the ability to update the navigation and menu structure of a site. |
| CMYK (Cyan-Magenta-Yellow-Black) | An alternate color scheme to the RGB color scheme. Combinations of cyan, magenta, yellow, and black are used to represent colors. The CMYK scheme is used mainly in print, such as magazines. Combining cyan, magenta, and yellow produces black, but that black is not always pure enough, thus, the addition of the K, for pure black. Color inkjet printers use CMYK to represent images. The best printers have separate black instead of wasting all the colors to print a faux brownish black. |
| CNAME | Canonical Name. A domain name alias. It allows a domain name to act as an alias for an existing domain. A CNAME record should point to either an "A record" (recommended) or another CNAME. |
| Co-Location | Most often used to refer to having a server that belongs to one person or group physically located on an Internet-connected network that belongs to another person or group. Usually this is done because the server owner wants their machine to be on a high-speed Internet connection and/or they do not want the security risks of having the server on thier own network. |
| COA | . Certificate Of Authentication (or Certificate of Authenticity). A paper document which certifies that an item is genuine. A COA is typically used where the certificate is easier to verify than the item. The COA is intended as an mechanism to help prevent piracy or imitation. For example Microsoft Windows comes with a COA which is normally stuck to the side of the PC on which Windows has been installed. Similarly some works or art (or even children's toys) come with a certificate of authenticity to help distinguish them from imitations or fakes. 2. Course (or Courses) of Action. |
| Coaxial cable | he type of cable used by the 10Base2 Ethernet standard, and also in most home cable television. It consists of a single, insulated copper wire, surrounded by a copper braid or foil that acts as a ground. The entire wire is then coated with plastic. |
| COD | Cash on delivery. Indicates that a purchase will be paid for at the point (or time) or delivery. |
| Code | A series of instructions that make up a program. |
| Code generator | A code generator is part of a compiler. It takes intermediate code and translates it into the final workable code in the target language. |
| Codec | No, this is not just a cheap rip-off of Kodak. The name "codec" is short for "coder-decoder," which is pretty much what a codec does. Most audio and video formats use some sort of compression so that they don't take up a ridiculous amount of disk space. Audio and video files are compressed with a certain codec when they are saved and then decompressed by the codec when they are played back. Common codecs include MPEG and AVI for video files and WAV and AIFF for audio files. Codecs can also be used to compress streaming media (live audio and video) which makes it possible to broadcast a live audio or video clip over a broadband Internet connection. |
| Collision | What happens on a piece of networking equipment, usually a shared hub, that is being asked to transfer more data than it can handle. Collisions occur when a client on the network tries to transfer data and has to retry because the device is busy and the data figuratively “collides” with other data on the network. |
| COM | 1. Component Object Model. Defined by Microsoft. |
| COM Port | An abbreviation for communications port, this generally refers to a serial port. |
| command key | A key on Mac keyboards only that is used to access commands through the keyboard rather than the menus. commands are commonly shortcuts. |
| Command Prompt | Any blinking cursor waiting, or prompting, for user input. In DOS the C: prompt greets you on most systems–this is a type of command prompt. As well, if you use any version of Windows you can get to a DOS-looking window that allows you to type in commands. UNIX can also greet you with a command prompt. For novice users a command prompt can be confusing, as it’s unclear what to do next; but for experts a command prompt is a necessity at times. |
| 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. |
| Compact Flash | Often abbreviated as simply "CF," Compact Flash is a type of flash memory. Compact flash cards are most commonly used for storing pictures in digital cameras, but are also used in devices such as PDAs and portable music players. There are two types of Compact Flash cards, creatively named "Type I" and "Type II." Type I cards are 3.3 mm thick, while Type II are 5 mm thick. IBM makes a "MicroDrive" card that has the same dimensions as a Type II CF card, but uses an actual hard drive construction rather than flash memory. Compact Flash cards originally could only store a few megabyes of data, but now can store several gigabytes. The new CF+ standard can store a possible 137 GB of data. I don't know about you, but I'd think about backing up that information before throwing the card in my pocket. |
| Competitive Intelligence | Competitive Intelligence is espionage using legal, or at least not obviously illegal, means. |
| Compile | When programmers create software programs, they first write the program in source code, which is written in a specific programming language, such as C or Java. These source code files are saved in a text-based, human-readable format, which can be opened and edited by programmers. However, the source code cannot be run directly by the computer. In order for the code to be recognized by the computer's CPU, it must be converted from source code (a high-level language) into machine code (a low-level language). This process is referred to as "compiling" the code. Most software development programs include a compiler, which translates source code files into machine code or object code. Since this code can be executed directly by the computer's processor, the resulting application is often referred to as an executable file. Windows executable files have a .EXE file extension, while Mac OS X programs have an .APP extension, which is often hidden. |
| Compiler | compiler is a software program that compiles program source code files into an executable program. It is included as part of the integrated development environment IDE with most programming software packages. The compiler takes source code files that are written in a high-level language, such as C, BASIC, or Java, and compiles the code into a low-level language, such as machine code or assembly code. This code is created for a specific processor type, such as and Intel Pentium or PowerPC. The program can then be recognized by the processor and run from the operating system. After a compiler compiles source code files into a program, the program cannot be modified. Therefore, any changes must be made in the source code and the program must be recompiled. Fortunately, most modern compilers can detect what changes were made and only need to recompile the modified files, which saves programmers a lot of time. This can help reduce programmers' 100 hour work weeks before project deadlines to around 90 or so. |
| 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. |
| Compression | To reduce in size. The amount of storage space required to store data can be reduced if the data is compressed. Compression can be achieved either without loss of information (called lossless) or may result in some loss of information (called lossy). Lossy compression algorithms typically allow a choice between low compression and low data loss or high compression with correspondingly higher data loss. Lossless compression is used for compressing where no data loss can be tolerated, for example when compressing applications or application data. Lossy compression is used where some data loss can be tolerated and is typically used for images, for example jpeg and mpeg are lossy image compression techniques |
| Computer | Technically, a computer is a programmable machine. This means it can execute a programmed list of instructions and respond to new instructions that it is given. Today, however, the term is most often used to refer to the desktop and laptop computers that most people use. When referring to a desktop model, the term "computer" technically only refers to the computer itself -- not the monitor, keyboard, and mouse. Still, it is acceptable to refer to everything together as the computer. If you want to be really technical, the box that holds the computer is called the "system unit." Some of the major parts of a personal computer (or PC) include the motherboard, CPU, memory (or RAM), hard drive, and video card. While personal computers are by far the most common type of computers today, there are several other types of computers. For example, a "minicomputer" is a powerful computer that can support many users at once. A "mainframe" is a large, high-powered computer that can perform billions of calculations from multiple sources at one time. Finally, a "supercomputer" is a machine that can process billions of instructions a second and is used to calculate extremely complex calculations. |
| Computer Emergency Response Team (CERT) | An organization that studies computer and network INFOSEC in order to provide incident response services to victims of attacks, publish alerts concerning vulnerabilities and threats, and offer other information to help improve computer and network security. |
| Computer Ethics | Ethics is a set of moral principles that govern the behavior of a group or individual. Therefore, computer ethics is set of moral principles that regulate the use of computers. Some common issues of computer ethics include intellectual property rights (such as copyrighted electronic content), privacy concerns, and how computers affect society. For example, while it is easy to duplicate copyrighted electronic (or digital) content, computer ethics would suggest that it is wrong to do so without the author's approval. And while it may be possible to access someone's personal information on a computer system, computer ethics would advise that such an action is unethical. As technology advances, computers continue to have a greater impact on society. Therefore, computer ethics promotes the discussion of how much influence computers should have in areas such as artificial intelligence and human communication. As the world of computers evolves, computer ethics continues to create ethical standards that address new issues raised by new technologies. |
| Computer model | A computer model is a recreation of a static scene, be it a house or a complex CAD design. |
| Computer Network | A collection of host computers together with the sub-network or inter-network through which they can exchange data. |
| Computer simulation | A prediction of the outcome of events by using actual data and attempting to mimic the environment on a computer. Computer simulations are used often in predicting the weather. |
| Confidentiality | Confidentiality is the need to ensure that information is disclosed only to those who are authorized to view it. |
| Configuration | This is a general-purpose computer term that can refer to the way you have your computer set up. It is also used to describe the total combination of hardware components that make up a computer system and the software settings that allow various hardware components of a computer system to communicate with one another. |
| Configuration Management | Configuration Management is a discipline to ensure that the configuration of an item (and its components) is known and documented and that changes are controlled and tracked. Sometimes abbreviated as CM. |
| Configure | The act of changing software or hardware actions by changing the settings. |
| Connect | A term that commonly refers to accessing a remote computer; also a message that appears at the point when two modems recognize each other. |
| Connection Failover | Connection Failover Where if the server that an application wants to connect to is unavailable then a connection is made instead to a second server. Connection Failover is different to Application Failover, although the two are often implemented together to provide a fault tolerant solution. |
| Connection Oriented Protocol | A protocol where a connection must be established before hosts can exchange data. TCP is an example of a connection oriented protocol. cf Connectionless protocol. |
| Connectionless Protocol | A protocol where there is no handshaking between the sender and receiver. In a connectionless protocol neither the delivery of messages nor the correct sequencing of messages is guaranteed. UDP is an example of a connectionless protocol. |
| Connectivity | A general term indicating the ability to connect two or more items. Generally used when referring to one of: Network connectivity - connecting and communicating between two or more computers. Database connectivity - connecting to and communicating with a database. |
| Console | This term can be used generally to describe a computer, a terminal, or, more recently, a dedicated gaming system. |
| Contextual Menu | A contextual menu is a pop-up menu that appears when you right-click on a certain area of the screen. It is "contextual" because the menu options are relevant to what you click on. While not all programs support contextual menus, most modern operating systems and applications include them as part of the interface design. Contextual menus provide a choice of options that depend on where the cursor is when you click the right mouse button. For example, if you right-click on your computer's desktop, the menu that appears will have desktop-specific commands. These may include options to change the desktop background, create a new folder, clean up the icons, or view the desktop properties. If you right-click within a desktop window, you might see options to create a new folder, change the view options, or view the folder properties. Right-clicking within an application typically provides menu options that are specific to the current program. For example, if you right-click in a Web browser window, the menu that appears may include options such as "Back," "Reload," and "Print." Right-clicking a misspelled word in a word processing program often presents a list of similar correctly spelled words. If you right-click a picture in an image-editing program, you may see a choice of editing options. These are just a few examples of the many contextual menus included in different programs. It may be helpful to think of a contextual menu of as a streamlined menu bar. This is because they typically contain many of the same options as the program's main menu, but only include the choices relevant to the location you clicked. Therefore, contextual menus can be a quick and efficient way of selecting the option you need. So next time you use your favorite program, try right-clicking in different areas of the screen. You might find some pretty useful options you didn't even know existed! |
| 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. |
| Controller | A device that manages the flow of data between a computer and a peripheral. Specific devices have their own kinds of controllers. PCs come with controllers for standard built-in devices such as hard drives, keyboards, and monitors. But other add-on peripherals may require expansion cards with new controllers. |
| Controller Card | The controller card, or simply "controller," is a piece of hardware that acts as the interface between the motherboard and the other components of the computer. For example, hard drives, optical drives, printers, keyboards, and mice all require controllers to work. Most computers have all the necessary controllers built in the motherboard as chips, not full-sized cards. However, if you add additional components such as a SCSI hard drive, you may need to add a controller card as well. Controller cards are typically installed in one of the computer's PCI slots. |
| Convergence | The ability of the three electron beams (red, green, and blue) in a CRT monitor to meet at a single point and produce one dot. If a monitor is mis-converging, you will notice shadows of blue or red around any white images. Often, this will occur in only some parts of the screen. Some CRT monitors have convergence controls, but most do not, making it impossible to correct this condition without opening it up, which isn’t a good idea due to how CRT monitors hold electrical energy. |
| Cookie | Data stored locally by a browser when it visits a website, used to stored information to customise the browsing experience - for example name and language selections. |
| Cooperative Multitasking | Cooperative Multitasking Multitasking operating system strategy in which each process has complete control of the system until it voluntarily relinquishes control. Cooperative multitasking systems are much simpler to design than pre-emptive multitasking systems, but suffers if one process hogs the processor. cf preemptive multitasking. |
| Copy | Many software programs allow you to copy data, such as text in Microsoft Word or an image in Adobe Photoshop. To copy a piece of data, you need to first select it (or highlight it) and choose "Copy" from the Edit menu within the program. Most programs allow you to use the keyboard shortcut "Control-C" for Windows or "Command-C" for the Mac OS. When you copy a piece of data, it is moved to a buffer in the system's memory called the "Clipboard." This is a temporary storage area in your computer's RAM that holds the most recent item that has been copied. Of course, copying isn't very helpful if you can't use the data somewhere else. To insert the copied data into a document, choose "Paste" from the Edit menu and the data will be pasted into the document. |
| Core | In UNIX systems this term is commonly used in reference to memory, and the crash dump “core” files you will find if you do something naughty in UNIX. The term goes back to when memory chips were actually magnetic coils, or core memory. Yeah, I want my enterprise systems running on that! Just kidding, real core memory hasn’t been built into systems in many, many years. |
| Core Dump | In UNIX systems, when a program crashes it “dumps” out an image of the memory and registers so that you may go through and see what caused the problem. This is almost as useful as the Netware and Windows NT memory dumps (which is not very, if you can’t taste my sarcasm). The problem is that if you really have to know what’s going on at a low level, you won’t understand the dump–not many people can do that. However, if the problem is important enough and persistent enough, the dump gives knowledgeable developers/admins something to look at in order to try to fix the bugs in the system. |
| Corruption | A threat action that undesirably alters system operation by adversely modifying system functions or data. |
| Cost Benefit Analysis | A cost benefit analysis compares the cost of implementing countermeasures with the value of the reduced risk. |
| Countermeasure | eactive methods used to prevent an exploit from successfully occurring once a threat has been detected. Intrusion Prevention Systems (IPS) commonly employ countermeasures to prevent intruders form gaining further access to a computer network. Other counter measures are patches, access control lists and malware filters. |
| courseware | Software designed specifically for use in a classroom or other educational setting. |
| CPM | Stands for "Cost Per 1,000 Impressions," and is used in online advertising. CPM defines the cost an advertiser pays for 1,000 impressions of an advertisement, such as a banner ad or other promotion. An impression is counted each time an advertisement is shown. While some advertisers pay publishers an amount based strictly on impressions, most advertisers pay for individual clicks or leads generated from their advertisements. Therefore, in Web advertising, it may be more effective to measure pay per click (PPC) or pay per lead (PPL) rates. Either way, the advertiser's goal is to generate as many leads as possible by keeping the rates as low as possible. Web publishers also use the CPM to measure the revenue per 1,000 impressions. While technically this should be "revenue per 1,000 impressions," or RPM, the terms CPM and RPM are often used interchangeably from the publisher's perspective. |
| CPU | Central Processing Unit. The CPU is the part of a computer that executes machine code instructions and coordinates and directs the interaction of the different components of the computer. A typical computer has a single CPU, but some have dual (i.e. two) CPUs or even quad (i.e. four) CPUs. |
| Cracker | This is the common term used to describe a malicious hacker, though it also can refer to code breakers. Crackers get into all kinds of mischief, including breaking or “cracking” copy protection on software programs, breaking into systems and causing harm, changing data, or stealing. Hackers largely regard crackers as a less educated group of individuals who cannot truly create their own work, and simply steal other people’s work to cause mischief or for personal gain, not to promote understanding. |
| crash | A hardware or software problem that causes information to be lost or the computer to malfunction. Sometimes a crash can cause permanent damage to a computer. |
| CRAWLER or WEBCRAWLER | Same as Spider. |
| CRM (Customer Relationship Management) | A class of enterprise software that enables a large company to manage all contact (or “touches”) that it has with its customers. It would track, for example, calls to tech support, faxes, e-mails, direct mail, telephone contacts, and any other contact that a company would have with a customer and vice-versa. This information can be used for analysis of customer relationships, and gives salespeople an understanding of what to say when calling up a customer. |
| Cron | A UNIX/Linux daemon that allows tasks to be scheduled on a regular basis. The crontab command is used to schedule and view jobs. |
| Crontab | A UNIX/Linux command that allows you to view (crontab -l) or make changes (crontab -e) to the list of jobs scheduled to be run by the cron daemon. |
| Crop | When you crop an image or photo, you remove part of the image. This may involve cutting some of the image from the left, right, top, bottom, or any combination thereof. It may also mean just cutting out a small rectangular of the image. For example, your friend takes a picture of your family and leaves a good five feet of headroom above the tallest person. If you are going to use the photo as your Christmas card picture, you probably don't want half the picture to be filled with sky. Therefore, you can use an image-editing program to crop the top part of the image, leaving only a small area above the tallest person's head. If the camera was zoomed out too far, you may want to crop some of the sides as well. Most image editing programs include a crop function. Typically, you select a rectangular area using the mouse and click "Crop" to remove the area outside the selection. Once the image is cropped, the cropped section is discarded, leaving only the remainder. Therefore, if you are working with an original photo, you may want to create a duplicate file before cropping and saving it. Note that cropping is different than simply reducing a image's size, which involves lowering the image resolution. |
| 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. |
| Crossover Cable | An Ethernet cable using RJ-45 connectors, where one end of the cable has the order of the second two pairs of the 8 wires (green and orange) swapped. Instead of wires 1, 2, 3, and 6 going straight through, you have 1 going to 3, 2 going to 6, 3 going to 1, and 6 going to 2. (Thanks to DN for pointing that out.) You can use a crossover cable to directly connect two 10BaseT or 100BaseT network cards, basically making a network of two computers for easy file transfer or configuration of network printers or other devices. As well, crossover cables are often used to connect 10BaseT and 100BaseT hubs together. |
| Crossplatform | Software that can run on multiple types of computer systems. For example, the graphics program Adobe Photoshop and the word processor Microsoft Word are both available for the Windows and Macintosh operating systems. Therefore, Photoshop and Word are considered to be crossplatform applications. While "crossplatorm" is typically used to describe computer software, it can refer to hardware as well. For example, peripherals such as keyboards, mice, printers, scanners, and digital cameras that work on both Mac and PC are crossplatorm. Software and hardware that work on more than one platform are also called multiplatform. |
| CRT | Cathode Ray Tube. Most monitors and televisions (other than 'thin' LCD ones) use and are referred to as CRT monitors. Unlike LCD monitors, CRT monitors are characterised by being bulky and heavy (and can be prone to flicker because the image is repeatedly being redrawn each second). |
| Cryptanalysis | The mathematical science that deals with analysis of a cryptographic system in order to gain knowledge needed to break or circumvent the protection that the system is designed to provide. In other words, convert the cipher text to plaintext without knowing the key. |
| Crypto (Cryptography) | The study of decryption and encryption technologies |
| Cryptographic Algorithm or Hash | An algorithm that employs the science of cryptography, including encryption algorithms, cryptographic hash algorithms, digital signature algorithms, and key agreement algorithms. |
| Cryptography (crypto) | The study of decryption and encryption technologies. |
| CSS | Cascading Style Sheet(s). Extension to HTML allowing paragraph formatting to be defined once and then applied to multiple paragraphs in an HTML document. |
| CSV | Comma Separated Value. An ASCII text file containing values with comma delimiters (i.e. commas separating distinct fields). Occasionally, but by no means a standard, the first line may contain the names of the fields. CSV files are normally denoted with a .csv file extension. Most spreadsheet packages will import csv files directly and can also save a csv file. Some databases provide tools to import and/or export csv files. Some systems, when generating csv files, will place double quotes around strings others will not - there is no defining standard. |
| CSV (Comma Separated Values) | A file extension used for a flat text data file consisting of items of data separated by commas. Each line of data is separated by a carriage return. |
| CTR | Click Through Rate. Abbreviation used by affiliate networks. Is the percentage of the number of advertisement displays that resulted in a click. |
| CUPS | Common UNIX Printing System. CUPS provides a portable printing layer for UNIX based operating systems. |
| Cursor | The cursor on your screen can indicate two things: 1) where your mouse pointer is, or 2) where the next character typed will be entered in a line of text. The mouse cursor is most often an arrow that you can use to point to different objects on your screen. When the cursor is over an object, you can click or double-click the mouse button to perform an action on that object (such as opening a program). The mouse cursor can change into other images, such as a small hand (when you roll over a link in a Web page), or an hourglass (when Windows is "thinking" so hard, it won't let you click on anything). The text cursor is typically a straight vertical line or I-shaped object that flashes in a line of text. Typically, when you are typing a paper, the cursor will be at the end of the line, because you are adding new text to the uncharted white area of the page. However, if you want to insert a word or phrase somewhere else in a line of text, you can use the mouse cursor to click the position where you would like to insert the text. In most word processing programs, once you start typing, the text cursor continues to flash, but the mouse pointer disappears until you move the mouse again. This is to avoid "cursor confusion," since most people can't type and click on things at the same time. |
| CUSTOM SEARCH ENGINE (CSE) | A Google service in which individuals can create a Google account (free) and create a search engine directed to search within a group of websites or pages they select. More information at CSEs: Make Your Own Search Engine and Finding CSEs. |
| Cut | The Cut command removes a selected object and copies it to the clipboard. It performs both a Delete and Copy operation at the same time. After data has been cut from a document, it can be pasted into another similar document. Objects like text, images, audio, and video selections can be cut. However, only editable items can be cut since the command removes the selection from the document. |
| cut and paste | A type of editing in which data is copied or moved from one location to another. Example: rearranging paragraphs within a document. |
| Cut-Through | ut-Through is a method of switching where only the header of a packet is read before it is forwarded to its destination. |
| 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. |
| Cyberspace | Term originated by author William Gibson in his novel Neuromancer the word Cyberspace is currently used to describe the whole range of information resources available through computer networks. |
| Cyclic Redundancy Check (CRC) | A test to see whether data has been transferred properly over a modem or to and from disk media. The sender of the data adds a check number to the end of the data being sent, and the receiver applies the same check to the data and compares the number it gets with the check number. If they don’t match, the data can be requested again. |
| Cylinder | This term is somewhat synonymous with the tracks on a hard disk drive. However, instead of a single track, a cylinder refers to the location of all the drive read and write heads, typically accessing multiple platters. Thus, when these tracks are mentally pictured, they are stacked up like a cylinder. Since all the heads are locked together, a specific cylinder number is equivalent to a track number on a specific platter, but refers to all platters at once. |
