C2
The security level that Windows NT was given by the NCSC. It includes the following capabilities:
  • The owner of a resource controls access to the resource.
  • Users identify themselves when they logon.
  • Security related events can be audited.
C/C++
A structured programming language that was developed in 1972 by Ken Thompson and Dennis Ritchie (K & R) at Bell Labs. C was developed to overcome the limitations of B, which itself was based on BCPL, a language developed in 1967. Bjarne Stroustrup started work on C++ in 1979 at AT&T as an OOP version of C. The UNIX operating system is itself written in C. See programming languages.
cable modem
A cable that utilizes cable TV cable instead of phone lines. Compare the typical phone modem of 33.6 kb/s to cable modem's maximum of 30 Mb/s. Realistically, cable modem is typically 1.5 Mb/s for download and 300 kb/s for upload. Cable modem is a dedicated connection instead of dialup. However rates can vary depending on the usage of your neighbors.
cache
A portion of memory set aside for instructions and data frequently used. The main purpose is to increase speed. This is contrasted with buffering, whose main purpose is to provide uninterrupted data.

Cached data occurs at different levels:
  • On the macro level, i.e. at a organization, regional, national, or world level.
  • On your local network's proxy server.
  • Onto a particular directory on your local disk.
  • Onto a particular disk cache. 
  • Onto your computer's RAM cache. Memory caching utilizes the faster and more expensive SRAM instead of the slower and cheaper DRAM.
  • On your system's L2 cache memory, i.e. on a chip separate from the microprocessor.
  • On your system's L1 cache memory, i.e. on the same chip as the microprocessor.
CAD
Computer Aided Drawing. Aka Computer Aided Drawing. Technical drawings made by using computers. This includes dimensioning the items and providing different views of the item.
Caesar shift encryption
Simple encryption where given a set of N characters, a character is encrypted by shifting it X places. EG: If N=26 (for the 26 characters in English), and X=13, then the letter A would be encrypted as N because 1+13=14 and the 14th letter is N. Legend has it that the Roman Emperor Gaius Julius Caesar, (100 - 44 BC) utilized this sort of encryption. See also rot13.
CAL
Client access license. A model for software licensing where the software (usually server software) is sold with a number of CALs thus limiting the number of workstations that can access that server. EG: A Microsoft SQL Server 2005 Standard Edition server might be sold for $2,799 USD and it will come with 10 CALs. If many users will access the server, then it might be more cost effective to buy it at the $5,999 per processor price.
Call Level Interface
See CLI.
Call Progress Tones
See CPT.
carriage return
See CR.
Carrier Sense Multiple Access with Collision Detection
See CSMA/CD.
Cartesian product
Mathematically a Cartesian product of two sets (denoted as A x B) combines them into ordered pairs whose first member comes from the first set, and the second member comes from the second set. EG: Cartesian 2D space is defined as the set of (x,y), where x and y are real numbers. EG: Given a party with boys {A,B,C} and girls {1,2,3}, then the Cartesian product of boys x girls is {A1,A2,A3,B1,B2,B3,C1,C2,C3}.
Cascading Style Sheets
See CSS.
CASE
Computer Aided Software Engineering. Software that helps in the development of other software. CASE tools often include text editing, compilers, graphical data modeling, auto-normalization, and the automatic production of SQL statements.
cc
carbon copy. To send to additional recipients. To send to additional recipients without letting the others know, use bcc (blind carbon copy).
CCD
Charge-Coupled Device. A strip of light sensitive cells used in scanners to detect light and convert it into digital information.
CCITT
Consultative Committee for International Telephony and Telegraphy. See ITU.
CCP
Cut, Copy, and then Paste. A common operation done with clipboards for many applications.
ccTLD
See TLD.
CD
Compact Disc. 4.75 inch silicon disk with data encoded into it by laser. The data is inside the disk not on the surface so the data is better protected. A CD can hold 650 Mb; when run at the speed played to hear music this is 74 minutes. The CD players for computers can spin the disk faster since the data does not necessarily need to be heard as it is read. Thus you have players from double speed (2X) up to 24X and beyond.

CDs come out in different flavors:
  • CD-ROM (CD-Read Only Memory). Aka data CD. CD-ROM is the standard CD for computers. The binary 0s and 1s are etched or stamped into the disk itself. These disks have a bright metallic, iridescent appearance. ISO 9660 is the worldwide standard which specifies the logical format for files and directories in CD-ROMs.
  • CD-R (Recordable) can be written on once but then its just a CD-ROM. These are made by a laser burning into a dye layer between the reflective base and the protective plastic surface. The bluish or greenish dye is permanently removed. They come in blue/gray short term disks that last approximately five years and also in goldish long term disks that last approximately 100 years. Take care of these light sensitive disks
  • CD-RW (ReWritable) can be written on and re-written on multiple times. These disks have a crystalline layer instead of a dye layer. This material can be transformed from reflective to translucent and vice versa by the proper application of a laser. The disk can be reburned to have totally different data many times.
  • CD-I (Interactive). Aka the green standard. An unpopular variation. CD-I drives had their own microprocessors to access some of the special features in CD-Is.
  • CD-DA (Compact Disc-Digital Audio). The worldwide standard for digital audio CDs. This is the usual albums and songs that you buy at a music store. These hold up to 74 minutes of sound in up to 99 tracks.
Watch out CD! DVD is coming! See also removable storage.
CDFS
CD-ROM File System. A 32 bit driver for Windows 95 which enables systems to recognize and control CD-ROM players. CDFS utilizes the VCACHE. See also MSCDEX.
CD-ROM File System
See CDFS.
cell relay
A packet switching technology which utilizes small, fixed size packets called cells. Cells are faster and more predictable then packets or frames that vary in size, so cell relay can be used to carry real time data such as audio and video. ATM (Asynchronous Transfer Mode) is a type of cell relay protocol set by the CCITT utilizing 53 byte cells.
cellular
Wireless communication. Cell refers to the area of coverage of radio towers that send and receive data. These cell site towers are roughly 50 m tall and are spaced several km apart so the cells overlap.
Central Office Exchange
See centrex.
Central Processing Unit
See CPU.
centrex
CENTRal office EXchange. A type of PBX where the switching occurs at the local telco instead of on the company premises. The telco usually owns and manages all the necessary telecommunications equipment for the centrex and sell the service to companies.
CER
Character Entity Reference. CERs use symbolic names so that authors need not remember code positions. EG: For the character a with a grave accent (à), the NCR is either à or à, while the CER is à. See also NCR.
CGA
Color Graphics Adapter. A standard for video cards and monitors. It has a resolution of 640 x 200 pixels. See video standards.
CGI
(1) Computer Gateway Interface. A real time executable script (in something like Perl or AppleScript) or program (in something like C/C++ or Fortran) on a server which is accessed by a user. The CGI acts as a gateway by communicating with databases or other applications on the server/network and then returning the results in HTML format that can be read by the user's browser. See also ASP and IIS.

CGI is server-side programming. In contrast, client-side programming would use JavaScript, VBScript, or DHTML.
(2) Computer Generated Imagery. More of a Hollywood term describing special effects generated by computer.
channel
(1) A broadly applied term referring to a designated separate communication path between two points. Here are typical applications of the term:
  • TV channels and radio stations are transmitted, each with a distinct frequencies.
  • IRC servers can have a channel for each chat session.
  • The PSTN has multiple channels within a single link between network points. EG: A T1 line has 24 channels of digital data transmission, each of which has 64 kb/s.
  • DWDM, used  in optical fiber transmissions, has channels each of which is on a different wavelength, within a combined, multiplexed light stream.
  • In the Web, a channel is a Web site that can push or automatically send updated info to the client.
  • In mainframes a channel refers to a high bandwidth local connection. This is in contrast with a remote connection.
(2) A digital image is composed of pixels, eg 800 pixels by 600 pixels. Each pixel is a combination of channels of colors, eg RGB images have three channels, red, green, and blue. An image may contain additional channels called alpha channels which are used by certain applications to create special effects. See also RGB, CMYK, LAB, duotone, and alpha channel.

(3) In marketing speak, a channel is the middleman between vendors and the market. The channels in this sense are typically retail stores or VARs.
Channel Service Unit/Data Service Unit
See CSU/DSU.
character set
A list of characters numerically defined for recognition by computers. The most common is ASCII (Standard ASCII). Others include extended ASCII/high ASCII, ISO Latin, and Unicode. See also my section on Character Sets.
Charge-Coupled Device
See CCD.
chart
A graphical representation of data. See also graph.
chat room
A network service that clients can connect to and exchange text messages in relative real time. AOL has chat rooms for its members only. Yahoo! has chat rooms accessible by the Internet. Other chat rooms often utilize IRC. See also my article on Chat Room Shorthand.
checksum
A method that ensures the integrity of data in a transmission by seeing that the number of bits in a transmission unit are what they supposed to be. This is used by both TCP and UDP communication layers.
CHRP
Common Hardware Reference Platform. Aka PPCP. A computer hardware system developed by Apple, IBM, and Motorola that can run MacOS, Windows NT, OS/2, UNIX OS, Solaris (Sun's UNIX OS), AIX (IBM's UNIX OS), and Novell's NewWare.
chmod
A UNIX command which CHanges the access MODe of files, eg chmod 755 gives permission for the owner of the file to read, write, and execute whereas the group the file is in and the world are only given permission to read and execute.
chrome
Showy, flashy features added to a program that attracts users but does not contribute to the power of the system. The term chrome is sometimes used in a derogatory manner. Bells and whistles are added for the programmer's sake whereas chrome is added for the user's sake.
CIDR
Classless Inter Domain Routing. Routing routine used by routers to refer a packet of information to a bigger provider which probably has the table to figure out where the packet should go. This saves each router from having to store such a table.
CIL
Components Integration Labs. A consortium of computer vendors, including IBM, Apple, and Novell, interested in component technologies. They put together the OpenDoc object standard, an attempt to compete with Microsoft's ActiveX. See also OMG.
CIR
Committed Information Rate. The guaranteed line bandwidth (in b/s) available in frame relay, DS1, or DS3 service.
circuit switching
The protocol of establishing a dedicated channel, i.e. circuit, to transmit real time data like audio and video for the duration of the transmission. Circuit switching is used for telephone calls.

In contrast to circuit switching, packet switching breaks up info (like e-mail or web pages) into packets and sends them out. ATM (asynchronous transfer mode) tries to utilize both types of switching.
CISC
Complex Instruction Set Computing. A processor design that is slower than RISC but more common. Macs in the 68000 series and Pentiums use CISC chips. See also CPU.
CJK
Chinese-Japanese-Korean text. There are over 31,000 ideographs that form the Chinese, Japanese, and Korean languages. Luckily the Han dynasty (3rd century A.D.) codified a majority of the characters to form Hanzi in Chinese, Kanji in Japanese, and Hanja in Korean.
class
Aka type. A class is template for items with fundamentally similar characteristics (much like the ancient Greek philosophic concept of "forms"). Classes are stored in type libraries and are often viewed with object browsers. The class defines, amongst many things, the object's interfaces. Creating with a class is instantiating an object.

The interface is the set which exposes the members of an object. An object can have multiple interfaces to support inheritance and polymorphism. Inheritance allows changes in the class to propagate to its objects. Polymorphism is coding for members that are very similar the members of other classes or objects. Classes themselves are hierarchical, eg the human class can have sub-classes of men and women.
CLI
(1) Command Line Interface. Any interface which involves entering text that calls methods or functions. A CLI may be for the operating system (EG: The ksh (Korn shell) for Unix) or for an app (EG: Most RDBMS have a CLI for entering SQL). See also shell.

(2) Common Language Infrastructure. The foundation of Microsoft's .NET strategy. Different languages like C#, VB .NET, and J .NET meet the CLS (Common Language Specification) if they can access a common class library, support CTS (Common Type System) data types, and can be compiled into CIL (Common Intermediate Language) bytecode. CIL bytecode can be run via a CLR (Common Language Runtime) virtual machine. CVMs only work for versions of Windows whereas JVMs exist for most operating systems.
click
To move the pointer over the desired item or area and then press and let go the button on the mouse. In Windows this usually means the left button.
client
In software, a client is an application or user that taps into resources "served" up by another application called a server.

In hardware, a "dumb client" is hardware that merely accesses a server which does all the processing work.

In a true client/server setup, the client and server share the processing workload.
client access license
See CAL.
client-server architecture
Two-tier model. The second kind of computer network in which the users or clients have the user interface and applications while tapping into a server which has the data. An example would be a Windows NT server and Windows 95 clients.

Dumb clients let the server do all the processing work. Dumb servers only provide access to files and/or a printer but let the clients do all the processing work. In a true client/server setup, the client and server share the processing workload. See also mainframe architecture and NCA. See also my article on Tier Architecture.
clip art
Ready made illustrations that are usually royalty free.
cluster
To have several servers working together to function as one server.
CMOS
Complementary Metal Oxide Semiconductor. A memory chip that retains can retain its data even when the power is off--as long as the computers battery is running. It stores the computer's basic system configuration and any changes to it. See also PRAM.
CMS
Content Management System. Aka Content Management Software. CMS is used to organize and facilitate the collaborative creation of content. A CMS is often implemented over the web so that users can work on website content, newspapers, real world documents, etc.
CMYK
Cyan Magenta Yellow Black. The four ink hues that compromise most commercial process color prints. The range of colors produced by CMYK is less than the range of RGB.
coaxial cable
See 10BASE-X and media.
COBOL
COmmon Business Oriented Language. A high level programming language developed in 1959 by a group called CODASYL Committee (COnference on DAta SYstems Languages). It is designed for high volume commercial applications such as payroll and inventory. It is less suitable for more complex calculations as is commonly found in the sciences. It is very wide spread and can be compiled on many different machines. The most common versions are ANS COBOL 68, 74, and 85.
codec
COmpressor-DECompressor. Aka endec (ENcoder-DECoder). A device or program that transforms a data stream or signal. The data is compressed or encrypted or otherwise encoded, and back again. Often the raw data encoded is "essence" (audio or video or both) plus some metadata (which syncs the essence, provides titles & subtitles, etc.). Compression may be lossy (some data lost) or lossless. The resulting data encoded by a codec is then stored in a file format. Some file formats store only one kind of codec while others take more. Some "super" file formats (ASF, Matroska, Ogg, and Quicktime) store a wide variety of video or audio codecs. A codec is usually software, while an endec is usually hardware. See also Sound and Video for more codecs and file formats.
ColdFusion

ColdFusion is a set of products made by Allaire for building and serving Web sites. Content is entered via user friendly ColdFusion templates and stored in a database. The content is then reassembled, structured, formatted, and administered via ColdFusion Studio. ColdFusion Server then uses CFML (ColdFusion Markup Language) to serve up the content dynamically. CFML is their particular mix of HTML and XML (Extensible Markup Language). ColdFusion can connect to different databases using OLE DB or ODBC. ColdFusion can also work with distributed components via CORBA and DCOM.

collection
In OOP (Object Oriented Programming), this is an object that has a group of objects of the same class. Objects within a collection are said to be members of the collection. The objects within a collection can be referred to by qualifying the object with the collection name. EG: Controls("List1"), Controls!List1, Controls.List1, or Controls(3) .
color
There are many systems to define color. Most utilize the color wheel model. In a color wheel, the color spectrum (rainbow) is evenly spaced. See also my section on Color. See also video card and monitor.
Color Graphics Adapter
See CGA.
color wheel
A wheel where the color spectrum (rainbow) is evenly spaced. The hues of red, yellow, and blue form an equilateral triangle on the circle. Those hues are connected by gradations of different hues.
columnated
A table of data stored as plain text and using position (column) and line (row). EG: positions 0-49 is for the Name column, 50-59 is for the Phone Number column, and a carriage return (char(13)) marks the end of a row.
COM
(1) COMmunication port. The name of serial communication ports in DOS systems. DOS has four COMs: COM1, COM2, COM3, and COM4. Four devices may be put on the ports. There is a silly quirk in the OS: although there are 4 ports, they typically share two IRQs. Most software use the IRQs to access the ports. EG: Since COM2 and COM4 usually share IRQ3, and COM1 and COM3 usually share IRQ4, you would not be able to use devices on COM2 and COM4 simultaneously!

(2) Component Object Model. A model developed by Microsoft for binary code. In the model, programmers can develop objects that can be accesses by any COM compliant program. OLE and ActiveX are both based on COM. COM is Microsoft's counter to OMG's CORBA and IBM's SOM. The distributed objects version of COM is called  DCOM (Distributed COM). DCOM is Microsoft's counter to IBM's DSOM and Sun's RMI. DCOM however is only implemented on Microsoft Windows.
COM+
COM for Windows 2000. It utilizes MTS TP monitor and MOM.
com
.com. Dos files that are like .exe but are usually utilities.
comma delimited
See csv.
command.com
A file invoked at startup after config.sys is accessed on PCs. It contains key parts of the OS and initiates the autoexec.bat.
comment
Annotations added to programming code to help programmers decipher the program. See also my article on Language Features.
Common Hardware Reference Platform
See CHRP.
Common Language Infrastructure
See CLI.
Common Object Request Broker Architecture
See CORBA.
compiler
An application that takes the source code of a program, optimizes it, and makes an executable file out of it, eg Java. In other word it translates a high-level symbolic language program, written in ASCII text, into a low-level machine language program. By distributing the executable instead of the source code, a programmer takes a step to keep the program details confidential. Some languages do not need to be compiled but can be interpreted directly with an interpreter.
Complex Instruction Set Computing
See CISC.
component software
Small pieces of programming that concentrate on only a few functions and are more easily developed and tested than large applications. Although each component is free standing, they are meant to be used cooperatively with other components, thus acting like a large application and reducing the duplication of tasks. Plug-Ins are examples of component software.

Components should cooperate, self-install, be certifiably safe, and be small. Four big component makers are Apple's OpenDoc, Microsoft's ActiveX/COM, Sun's JavaBeans, and OMG's CORBA (Object Management Group's Common Object Request Broker Architecture).
Components Integration Labs
See CIL.
COM port
A serial port on the PC.
compound document
A document made by one application that can also contain or be linked to documents made by different applications. For Windows OS, OLE makes compound documents by utilizing the component software technology of ActiveX. For Mac OS, Publish and Subscribe makes compound documents utilizing the component software technology of OpenDoc.
compress
To reduce the size of a file. It must be decompressed before use. Examples include .sit, .zip, and .gz.
computer
A device which is used to store, transmit, and process data. The data is in binary form and can represent text, graphics, sounds, and other information. A user utilizes software to provide instructions which manipulate the data through the physical hardware.
Computer Aided Drawing
See CAD.
Computer Aided Software Engineering
See CASE
Computer Gateway Interface
See CGI.
Computer Telephony Integration
See CTI.
concatenate
To link together, eg Bat + man becomes Batman.
concentrator
See hub.
condition
An expression which is concerned with evaluating for a boolean truth value (true or false).
config.sys
A DOS file that can be modified by the user and is invoked at startup of PCs. It tells the OS how to handle certain operations, eg how many files can be opened at a time, how many buffers, and which drivers to load.
connector
The part of the wire, cable, or other medium that connects to other pieces of medium or ports/interfaces on various devices. Most connectors are either male (with prongs or pins) or female (with receiving holes or slots). See also my article on Media.
constant
A meaningful name that take the place of text string or number that doesn't change, eg pi is a mathematically fixed number. In programming it is more efficient to use constant instead of variables whenever possible because it takes less memory, is more legible, and is unaffected by program-wide changes.
Consultative Committee for International Telephony and Telegraphy
See CCITT.
container
In OOP, this is an object that that has a group of objects of one or more related classes. EG: A form object can contain objects from different classes.
content type
See MIME.
contrast
The degree of separation between values.
control
(1) The button on the keyboard usually marked "CTRL". This button is usually simultaneously pressed with another button to perform particular function. Some of the most common keyboard shortcuts using control are: CTRL-S (Save), CTRL-A (Select All), CTRL-C (Copy), CTRL-V (Paste), CTRL-P (Print), CTRL-N (New Document), CTRL-O (Open Document), and CTRL-F (Find). See also my article on Shortcuts for Windows.

(2) Aka widget. Interface elements such as command buttons, check boxes, pull down lists, etc., through which a user communicates or "controls" an application. By analogy, the controls of a car include the steering wheel, brakes, light switch, and speedometer.
controller
A device, often a chip or a card, that controls data transfer between the computer and its peripherals. Most computers come with controller chips for standard devices like disk drives, display screens, keyboards, and printers. Additional devices often require the installation of an expansion card like AT bus, PCI, or SCSI.
control panel
Mini-applications, many of which come with the operating system, that modify the functionality of elements of the computer such as the mouse or keyboard. For the Mac OS prior to System 7, these were known as cdev, components, or shared libraries.
control structure
See flow control.
conventional memory
The first 640 kB of RAM in older PCs running under DOS. The programs then had could only utilize this amount of memory. See also upper memory.
cookie
A text file initially sent from certain web sites to a web browser and then stored on the web browsers machine. When the user goes to that site again, the web server checks the cookie. The cookie stores information which can customize the site for the user. This includes information such as your usage, your preferences, and your username and password for the site. Cookies can not make viruses, look at other data on your computer, or overpower other cookies. Persistent cookies have a typical life span of 6 months since its last usage. Session cookies self-destruct when you leave the website.
cooperative multitasking
See multitasking.
CORBA
Common Object Request Broker Architecture. A framework developed by OMG (Object Management Group), a consortium of over 500 computer vendors. CORBA is sanctioned as the standard architecture for distributed objects by the ISO and X/Open. DSOM and OpenDoc are distributed object protocols that are CORBA compliant. COM is Microsoft's counter to CORBA although CORBA objects can communicate with COM servers and COM objects can communicate with CORBA servers.

The core concept of CORBA is the ORB (Object Request Broker) concept. Basically ORB handles communication between objects such as server apps and client apps so that the apps don't have to know the specifics of each other. LAN communication is handled with GIOP (General Inter-ORB Protocol), while Internet communication is done by IIOP (Internet Inter-ORBB Protocol) which basically maps GIOP communication to TCP.
CPT
Call Progress Tone. Tones transmitted across a phone line that indicate the status of the call. This includes the busy signal, the dial tone, the ringback (i.e. the phone is ringing sound), and the fast-busy tone. EG: The North American busy signal has a cadence of 500 ms of sound (at a pitch of 480 and 620 Hz) alternating with 500 ms of silence. The CPTs for a PBX should differ slightly from the CPTs of the PSTN.
CPU
Central Processing Unit. The core of a computer, i.e. the processor, the ALU, and the internal memory. It is composed of the main silicon chips of the computer which do the actual processing, as opposed to supporting services. See also my section on CPUs.
CR
Carriage Return. ASCII decimal code 13. VB chr(13). A CR indicates the end of a line while LF indicates a new line. It is common to use both CR and LF.
CrLf
Carriage Return and Line Feed. ASCII decimal codes 13 and 10 respectively. It is common to use both CR and LF.
cruft
(1) In regular English, cruft is dust that you have a hard time sweeping up or getting out from under your bed, i.e. dust bunnies.

(2) In regular English, cruft is the result of shoddy construction, i.e. cruft instead of craft.

(3) To write directly write assembly code for stuff that would normally (and usu. preferably done by a compiler).

(4) Excess; superfluous junk; redundant or superseded code.

(5) At the University of Wisconsin, a cruft is a group of hackers, i.e. "a cruft of hackers".
Cross-Site Scripting
See XSS.
CRUD
Create, Read/Retrieve, Update, and Delete/Destroy. The four basic functions of persistent storage. These four major functions correspond to these four SQL statements: INSERT, SELECT, UPDATE, and DELETE.
CSMA/CD
Carrier Sense Multiple Access with Collision Detection. See Ethernet.
CSS
(1)Cascading Style Sheets. A feature of HTML developed by the W3C that is utilized by browsers of version 3 or later. Style sheets are templates that define how different elements such as headers and margins are displayed. The style sheets can be cascaded because an HTML page can accept multiple styles sheets.
(2)See XSS (Cross-Site Scripting).
CSU/DSU
Channel Service Unit/Data Service Unit. The CSU does performs diagnostic and protective functions for a telecommunications line. The DSU is very much like a super-modem in that it converts digital data to analog signals, but it is used for dedicated phone line. CSUs and DSUs are usually coupled together and are used for higher speeds such as 56 kb/s, T1, or T3. Usually the two ends of such a connections will have CSU/DSUs by the same manufacturer.
csv
.csv. Comma Separated Values. A text file where each individual field of information is delimited by commas. This is a common format for importing and exporting data between different kinds of databases. Spreadsheets usually open csv files as a spreadsheet. See also CVS.
CTI
Computer Telephony Integration. Systems where a computer accepts, handles and routes phone calls. This has spread to include incoming and outgoing phone calls, faxes, and e-mail.
CTRL
ConTRoL. Usually refers to the key on the keyboard marked as such. The Mac equivalent is the Command key, marked with something like a four-leaf clover. The CTRL key is usually combined with another key to perform something. These are common shortcuts: CTRL-x (cuts), CTRL-c (copies), CTRL-v (pastes), CTRL-z (undoes), CTRL-o (opens), CTRL-p (prints), and CTRL-f (finds). In a Unix context the CTRL key is sometimes abbreviated as "C". EG: C-/ is the same as CTRL-/.
Cupertino, CA
Apple's HQ.
cursor
(1) A special symbol that signifies the point of interaction on a computer screen. In command lines or text, the cursor is usually a solid rectangle, a blinking vertical line, or a blinking underscore, that can be moved around with the keyboard. If the application or operating system has a GUI (graphic user interface), there may be a cursor for text and second cursor that follows the mouse or pointer device. A GUI cursor has many symbols including arrows, hands, I-beams, hourglasses, and animated dogs.

(2) Aka puck. A pointing device, similar to a mouse, used for high precision digital tablets.

(3)CURrent Set Of Records. In databases and database APIs, the cursor is literally the current set of records, a mechanism for storing and using at least a portion of a record set, particularly the current row in the record set. There are different options available when choosing a cursor.
  • Location. The cursor is either built either on the client or the server.
    • Client cursors are good for spreading the workload across many workstations.
    • Server cursors are good for lightweight clients dealing with large record sets.
  • Membership/Cursortype. Which rows are in the cursor. Also what activity by other users the cursor is aware of (deletions, changes, or new rows). Obviously the latter cursors are more complete but also use more resources.
    • Static cursors (aka snapshot or insensitive) do not detect changes to rows, or new or deleted rows. Good for displaying data that does not need to be modified.
    • Keyset cursors detect changes to rows, but not new or deleted rows.
    • Dynamic cursors detect changes to rows, as well as new or deleted rows.
  • Scrolling Ability
    • Scrollable cursors can move forward and backward and can also set bookmarks to desirable records.
    • Forward-Only cursors can only go forward but are fast and light.
  • Updating Ability
    • Updateable cursors can be updated directly.
    • Read-Only cursors are fast and light and can still be updated with action queries if necessary.
It should be noted that Microsoft's ADO only allows four cursors: Keyset (1), Static (3), Dynamic (2), and Forward-Only (0, the default; it is like a forward-only static cursor). ADO does however let you decide the cursor location, but if a client-side cursor is chosen, then it has to be a Static cursor.
CVS
Concurrent Versions System = Concurrent Versioning System. A revesion control system that is popular, no-cost, and open-source. The svn (Subversion) system was designed specifically to overcome the deficiencies of CVS. See also csv.
Cyan Magenta Yellow Black
See CMYK.
Cygwin
Cygnus+GNU+Windows. A Linux-like environment for Windows. Cygwin.com

2008-01-03 22:04:40Z