C

cable --
(programming) In a Scrollbar widget, the cable is the ``line'' on which the elevator moves. One end of the cable is connected to the anchor and the other is connected to the elevator. See also anchors and elevator.

cache --
(programming) A section of computer memory where the most recently used buffers, i-nodes, pages, and so on are stored for quick access.

callback --
(programming) A callback routine is a routine written by an application programmer and associated with a specific widget resource. The callback routine is invoked as a result of a specific activity associated with that widget (the widget calls back the program using that routine). For example, the XtNselect resource contains the name of the callback routine that is entered when a button is pushed or when a CheckBox is selected; the XtNverification resource contains the name of the callback routine to invoke when a TextField widget is exited. The act of associating the name of a callback routine with a widget resource is called registration. See also register.

Cancel button --
A button in some dialog boxes that closes the dialog box without implementing any changes. Click on the Cancel button with mouse button 1 to cancel any changes you have made.

canonical processing --
(programming) Terminal character processing in which the erase character, delete, and other commands are applied to the data received from a terminal before the data is sent to a receiving program. Other terms used in this context are canonical queue, which is a buffer used to retain information while it is being canonically processed, and canonical mode, which is the state where canonical processing takes place. See also raw mode.

cartridge tape --
A storage medium that consists of a magnetic tape wound on spools housed in a plastic container.

cascading menu --
A submenu that displays when you select certain menu items. A cascading menu provides additional menu items.

cast --
(programming) An expression which describes the nature or use of that which follows it to the interpreter. In FMLI, casts are used: to describe whether a file is a menu definition file, a form definition file, or a text frame definition file; to indicate how often to evaluate a descriptor.

CDE --
Common Desktop Environment. An initiative by SCO, Hewlett-Packard, Sun, IBM, Novell and Univel to further desktop consistency and interoperability between UNIX providers. CDE is the default desktop for UnixWare 7.

C shell --
An alternative UNIX System V shell supplied with the system. This shell, written by William Joy at the University of California at Berkeley, is known for its interactive features, such as the ability to recall and modify previous command lines. The C shell shell programming language has a syntax like that of the C language, hence the name. C shell is the standard shell on older versions of the Berkeley UNIX operating system found at many universities. To start a C shell from the command line, type csh and press <Enter>. See also Bourne shell and Korn shell.

channel --
Permits a system to exchange data using a single type of network communications protocol. It handles the mail transport protocol so that neither the operating system nor the rest of the mail transport system has to know about the intricacies of a particular mail transport protocol. Channels act not only as protocol handlers, but in some cases actually initiate the communications to the network or to another machine as needed. They also may convert address or message formats as necessary.

channel input program --
The program used by a channel to monitor and manage incoming mail. For example, /usr/bin/rmail is used by the UUCP channel. See also channel.

channel output program --
The program used by a channel to process outgoing mail. For example, /usr/mmdf/chans/uucp is used by the UUCP channel. See also channel.

channel queue --
The holding space used by a channel for incoming or outgoing mail that is waiting to be delivered. See also channel, channel input program, and channel output program.

character class table --
(programming) A character class table is used for character classification and conversion. The table is built by the commands chrtbl(1M) and wchrtbl(1M) and is located in the file /usr/lib/locale/LC_CTYPE.

character I/O --
(programming) The process of reading and writing to or from a terminal.

character device --
(programming) A device, such as a terminal or printer, that conveys data character by character. See also block device.

character driver --
(programming) The driver that conveys data character by character between the device and the user program. Character drivers are usually written for use with terminals, printers, and network devices, although block devices, such as tapes and disks, also support character access.

chat script --
A series of requests and responses that establish a connection between the operating system and a modem. Chat scripts for different types of modems are contained in the /etc/uucp/Dialers file.

checkbox --
An onscreen button that lets you select or deselect an option by clicking mouse button 1. When the checkbox is highlighted or colored, that option is selected. Checkboxes are used when you can select none, one, or more than one of a group of options. See also radio button.

child process --
See fork .

choices menu --
(programming) A menu that can be provided to show a list of possible entries to a form field. An FMLI application developer defines choices where appropriate using the rmenu descriptor.

chording --
If you have a two-button mouse, pressing both mouse buttons at the same time, known as ``chording'', is equivalent to pressing mouse button 2 on a three-button mouse.

class --
A file's class is indicated by a group of one to six characters that show its type, permissions, and ownership.

click --
To press briefly and release a mouse button. You click a mouse button; you click on an icon or onscreen button (by pointing to it and clicking the mouse button). When the mouse button is not specified, click refers to mouse button 1. See also double-click.

client --
1. In the SCO graphical environment, client usually refers to an application that creates a display on the screen. 2. (programming) The transport user in connection-mode that requests a transport connection. 3. SNMP software, usually run on a network management station, which requests MIB information and receives responses from an SNMP agent.

client mode --
The mode in which a host polls a time server that it might synchronize with, but will not respond to polls from the time server. When a host is operating in this mode, the time server it is polling is said to operate in server mode.

client title --
The title on a window. The title need not be the same as the string shown by the icon label.

Clipboard --
A utility that allows you to transfer information between applications or within an application. The Clipboard provides a temporary storage place for information and translates it from its original file format to the correct type, if necessary. See also data integration and file type.

clone driver --
(programming) A software driver used by STREAMS drivers to select an unused minor device number, so that the user process does not need to specify it.

CLTS --
(programming) Connectionless Transport Service.

command menu --
(programming) A menu provided automatically in FMLI applications that lists a sub-set of the FMLI built-in commands and any application-specific commands that have been defined in a commands file. Users can execute a command in the Command Menu by selecting it, as in any menu. The Command Menu can be made current by pressing the <CMD-MENU> function key.

commands file --
(programming) A script in which an FMLI developer can redefine or disable FMLI built-in commands, and define new, application-specific commands. The contents of a commands file are reflected in the Command Menu. Users can execute a command by selecting it from the Command Menu, or by typing it on the FMLI command line. A commands file is optional, but if one is written, it must be named as an argument when fmli(1) is invoked.

COM ports --
The name used to designate serial ports (COM1, COM2) on an IBM-compatible personal computer.

command --
1. A series of words or characters that send an instruction or request to the computer. 2. (programming) One of a set of executables, such as open and close, built into FMLI, to which descriptors of type command must evaluate. A command line consists of the command followed by its arguments. For example, the following command

$ cc file1.c file2.c

instructs the operating system to execute the C compiler program, which is stored in the file cc, and to use the source files file1.c and file2.c as input. A command line can extend over multiple terminal lines.

command alias --
An alternative name for a command. When you type the alias, the command is substituted for the alias. Aliases are useful when you remember commands by names other than their UNIX system names; for example, DOS users may think of dir rather than ls when they want to list a directory. Aliases are also useful for creating commands that perform several UNIX system commands at once.

command line --
1. The instructions you type at the shell prompt. Command lines can contain commands, arguments, and filenames. You can enter more than one command on a command line by joining commands with a pipe (|), or by separating commands using the command separator (;). The shell executes your command line when you press <Enter>. 2. (programming) The next-to-the-last line on the screen in FMLI applications, where users can enter an application's commands without using the menus provided in the application.

command separator --
The semicolon (;) serves as a command separator on the UNIX system. To issue several commands on one line, separate the commands with semicolons before you press <Enter>. For example, type ls; pwd and press <Enter> to list files and then print the working directory. Commands are executed in sequence as separate processes.

command substitution --
(programming) In a shell program, the text of a command surrounded by backquotes is replaced with the output from that command; the output is ``substituted'' for the command. See also backquoted expression.

compiler --
(programming) A program which reads a program file and translates it into the computer's internal machine code, which can then be executed faster than an interpreted program. The C programming language is a compiled language; programs in C must be passed through a compiler before they can be executed. See also interpreter.

composite widget --
(programming) A widget that is a parent of other widgets and physically contains other widgets. See also widget.

computer name --
The name by which the computer is known on the network. Each computer's name on the network must be unique.

configuration --
The arrangement of the software or hardware of a system, peripheral, or network as defined by the nature, number, and chief characteristics of its functional units.

configuration management --
The identification of a system's hardware, software, firmware, documentation, test fixtures, and test documentation and changes made to them throughout the development and operational life of the system. The current configuration and revision level of all components should be known so these components can be effectively and productively integrated, managed, and used.

connection establishment --
(programming) The phase in connection-mode that enables two transport users to create a transport connection between them.

connection-mode --
(programming) A circuit-oriented mode of transfer in which data is passed from one user to another over an established connection in a reliable, sequenced manner.

connection-oriented transport --
(programming) Connection-oriented transports are reliable and support byte-stream deliveries of unlimited data size.

connectionless transport --
(programming) Connectionless transports have less overhead than connection-oriented transports, but are less reliable and maximum data transmissions are limited by buffer sizes.

console terminal --
The directly connected terminal used for communication between the operator and the computer. See also system console.

constant --
(programming) A fixed quantity or string that is invariant throughout the execution of a process that refers to it.

construct --
(programming) A complex command in a programming language that controls the execution of a group of other commands. Constructs follow a rigid syntax, and often require one or more parameters to determine how they operate. The three most common constructs are branching constructs (which choose whether or not to execute a group of commands), looping constructs (which can repeatedly execute a group of commands), and modular constructs (such as functions, which group a collection of commands together in a single, new command).

container --
(programming) A widget that defines a region that holds zero or more sub-objects of a given type.

context-sensitive help --
A facility that provides information specific to the command, window, or part of the screen that you are currently using.

control --
A Desktop program that modifies or controls some aspect of your Desktop environment, such as colors, fonts, or startup behavior.

control area --
(programming) The area located directly under the header of a window. It is used to display command buttons if the application in the window provides them.

control character --
A character that was typed using the <Ctrl> key in conjunction with another key.

control key --
The control key is marked <Ctrl> on most terminals and is used as a modifier key. It is represented as <Ctrl> in this documentation. The control key can be compared with the <Shift> key because it is always used in conjunction with another key or mouse button. This is done by pressing and holding down the control key, pressing the required character or mouse button, then releasing both.

controller --
The circuit board that connects a device, such as a terminal or disk drive, to a computer. A controller converts software commands from a driver into hardware commands that the device understands. For example, on a disk drive, the controller accepts a request to read a file and converts the request into hardware commands to have the reading apparatus move to the precise location and send the information until a delimiter is reached.

controlling process --
(programming) A session leader that established a connection to a controlling terminal.

controlling terminal --
(programming) A terminal that is associated with a session. Each session can have, at most, one controlling terminal associated with it and a controlling terminal can be associated with only one session. Certain input sequences from the controlling terminal cause signals to be sent to process groups in the session associated with the controlling terminal; see termio(7).

control program --
A computer program that controls certain elements of Desktop configuration, including mouse configuration, colors, fonts, and session management. See also control.

conversation --
(programming) The negotiation and the data transfer between Source and Destination. Both tasks are accomplished through the selection mechanism.

Coordinated Universal Time --
The international standard reference time. It also corresponds to the local time at zero longitude. The standards pertaining to the definition and maintenance of Coordinated Universal Time, which effectively replaced Greenwich Mean Time (GMT) on 1 January 1972, are promulgated in Recommendation 460 of the International Consultative Committee for Radio (Comite Consultatif International de Radiodiffusion or CCIR) of the International Telecommunications Union. The CCIR is located at 2, rue de Varembe, 1211 Geneva 20, Switzerland. Responsibility for time standards in the United States rests with the Time and Frequency Division of the National Institute of Standards and Technology (NIST) in Boulder, Colorado.

core --
Core is a name commonly associated with main memory, although very little memory is still ``core''. A better term might be ``main memory''.

core file --
A core image of a terminated process saved for debugging. A core file is created under the name core in the current directory of the process. See also core image.

core image --
A core image is a copy of the memory image of a process. A file named core is created in your current directory when the operating system aborts an executing program. The file contains the core image of the process at the time of the failure. See also core file.

counter --
For SNMP, an object syntax type representing a non-negative integer, which increases monotonically until it reaches the maximum value (2[31] - 1), when it wraps back to zero.

crash --
Occurs when a hardware or software error condition occurs that causes the system to take itself out of service. For example, such conditions might occur when the system cannot allocate resources, manage processes, or respond to requests for system functions, or when the electrical power is unstable.

cyclic redundancy check (CRC) --
A way to check the transfer of information over a channel. When the message is received, the computer calculates the remainder and checks it against the transmitted remainder.

critical code --
(programming) A section of code is critical if execution of arbitrary interrupt handlers could result in consistency problems. The kernel raises the processor execution level to prevent an interrupt during a critical code section.

cron --
A command that creates a daemon that invokes commands at specified dates and times; see also daemon.

CSMA/CD --
Carrier Sense Multiple Access/Collision Detection.

control and status register (CSR) --
Memory locations providing communication between the device and the driver. The driver sends control information to the CSR, and the device reports its current status to it.

current --
(programming) The frame, menu item, form field, or activity in which the cursor is positioned. An element of the FMLI screen which is current is usually distinguished in some way from other screen elements being displayed the current frame; for example, it might be shown in bright video, while non-current frames might be shown in half-bright video. User input is processed by, or applies to, elements such as the current frame.

current context --
(programming) When using the GUI debugger, the current context for a Window Set determines what is displayed in each of the windows. The current context is determined by the current frame of the current process.

current directory --
See current working directory.

current frame --
(programming) When using the GUI debugger, the current frame, along with the current process, determines the current context. The current frame is shown with a pointing hand to its left in the Process Pane of the Context Window.

current process --
(programming) When using the GUI debugger, the current process, along with the current frame, determines the current context. The current process is shown with a pointing hand to its left in the Process Pane of the Context Window.

current program --
(programming) When using the GUI debugger, the current program is the program containing the current process. The current program can also contain other processes derived from the same executable file.

current working directory --
The directory where you are currently located. Use the pwd(1) command (print working directory) to see your current working directory. The current working directory is taken as the starting point for all relative pathnames. This directory is symbolically referred to as ``.'' in directory listings.

cursor --
A blinking or constant box, underline, I-shaped character, or other graphical image that shows your position in text. See also mouse pointer.

cut --
To remove a marked area of text to a clipboard so it can be inserted elsewhere. See also cut and paste.

cut and paste --
To move a block of text from one position to another, either within a file or between files or windows. The text is temporarily stored on a clipboard during the cut-and-paste operation. See also cut.

cylinder --
The set of all tracks on a disk that are the same distance from the axis about which the disk rotates.