WHL
`
`:
`
`(cid:12)(cid:12)(cid:13)(cid:13)(cid:12)(cid:12)(cid:12)(cid:13)(cid:13)(cid:12)(cid:12)(cid:12)(cid:13)(cid:13)(cid:12)(cid:12)(cid:6)(cid:17)(cid:12)(cid:12)(cid:12)(cid:9)(cid:12)(cid:18)(cid:12)(cid:12)(cid:14)(cid:12)(cid:1)(cid:10)(cid:5)(cid:13)(cid:19)(cid:1)(cid:13)(cid:13)(cid:20)(cid:11)(cid:12)(cid:15)(cid:16)(cid:21)(cid:8)(cid:7)(cid:13)(cid:12)(cid:12)(cid:13)(cid:12)(cid:12)(cid:12)(cid:13)(cid:12)(cid:13)(cid:12)(cid:12)(cid:13)(cid:12)(cid:13)(cid:6)(cid:2)(cid:3)(cid:3)(cid:4)(cid:22)
`0000 0000000000
`(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:6)(cid:4)(cid:4)(cid:7)
`
`0000200001 6844
`
`
`
`The masticumprehensive computing dictionary ever published
`V More than 00,000 entries
`
`
`
`(cid:56)(cid:49)(cid:44)(cid:41)(cid:44)(cid:40)(cid:39)(cid:3)(cid:20)(cid:19)(cid:20)4
`
`UNIFIED 1014
`
`
`
`

`

`IBM DICTIONARY
`
`OF COMPUTING
`
`
`

`

`
`
`
`E
`
`i
`
`IBM DICTIONARY
`OF COMPUTING
`
`Compiled and edited by
`GEORGE MCDANIEL
`
`f
`
`
`
`§
`-§
`
`
`
`
`
`w,-u.‘.‘
`
`McGRAW-HILL, INC.
`New York San Francisco Washington, D.C. Auckland Bogota’
`Caracas Lisbon London Madrid Mexico City Milan
`Montreal New Delhi San Juan Singapore
`Sydney Tokyo Toronto
`
`
`
`

`

`
`
`Limitation of Liability
`While the Editor and Publisher of this book have made reasonable efforts to
`ensure the accuracy and timeliness of the information contained herein, nei—
`ther the Editor nor the Publisher shall have any liability with respect to loss or
`damage caused or alleged to be caused by reliance on any information con-
`tained herein.
`
`Copyright © 1994 by International Business Machines Corporation. All rights
`reserved. Printed in the United States of America. Except as permitted under
`the United States Copyright Act of 1976, no part of this publication may be
`reproduced or distributed in any form or by any means, or stored in a data
`base or retrieval system, without the prior written permisssion of the pub-
`lisher.
`
`234567890 DOC/DOC 9987654
`
`ISBN 0-07-031488»8 (HC)
`ISBN 0-07~031489-6 (PBK)
`
`The sponsoring editor for this book was Daniel A. Gonneau and the
`production supervisor was Thomas G. Kowalczyk.
`
`Printed and bound by R. R. Donnelley & Sons Company.
`
`Tenth Edition (August 1993)
`This is a major revision of the IBM Dictionary of Computing, SC20-1699-8,
`which is made obsolete by this edition. Changes are made periodically to the
`information provided herein.
`
`It is possible that this material may contain reference to, or information about,
`IBM products (machines and programs), programming, or services that are
`not announced in your country. Such references or information must not be
`construed to mean that IBM intends to announce such IBM products, pro-
`gramming, or services in your country. Comments may be addressed to IBM
`Corporation, Department E37/656, P. O. Box 12195, Research Triangle Park,
`NC 27709.
`
`International Edition
`
`Copyright © 1994 by International Business Machines Corporation. Exclusive
`rights by McGraw-Hill, Inc. for manufacture and export. This book cannot be
`re—exported from the country to which it is consigned by McGraw-Hill. The
`International Edition is not available in North America.
`When ordering this title, use ISBN 0—07-113383-6.
`
`This book is printed on acid-free paper.
`
`
`
`

`

`
`
`[115]
`
`
`
`column function
`
`
`
`color space All the colors that can be represented by
`red, green, blue, cyan, magenta, yellow, black, and
`white.
`
`M color lookup table (CLUT)
`
`color lookup table (CLUT) (1) In the AIX operating
`system, synonym for color map.
`(2) In multimedia,
`
`
`synonym for color palette.
`
`the
`D network,
`1 station after it
`it all other data
`(T)
`
`
`
`
`
`
`
`ks where text is
`
`tion, the spectral
`JpOn the spectral
`1 response of the
`ition of
`incident
`it, including black
`)lor, direct color,
`
`color map (1) In AIX graphics, a lookup table in
`which each index is associated with a red, green, and
`blue value.
`Synonymous with color
`lookup table,
`color palette, color
`table.
`(2) In AIX Enhanced
`X~Windows,
`a set of color cells.
`A pixel value
`indexes the color map to produce RGB-intensities. A
`color map consists of a set of entries defining color
`values that, when associated with a window, is used to
`display the contents of the window.
`See also direct
`color, pseudocolor.
`(3) In AIX graphics, a lookup
`table that translates color indexes into RGB triplets.
`
`color subsampling In video systems, the technique of
`using less resolution for the color difference compo—
`nents of a video signal compared with the brightness
`component.
`
`color table (I) In System/38 graphics, a compilation
`of eight entries, each defining a color to be used in
`System/38 graphics, from which individual colors are
`selected. Many color tables can be defined, but only
`one can be current.
`(2) In AIX graphics, synonym for
`color map.
`
`color menu A menu in LinkWay and LinkWay Paint
`that lets the user select a color for use in drawing or
`in the fonts used in a text field object. CGA mode has
`three available colors. EGA and VGA have 16 avail—
`able colors. MCGA 256 has 256 available colors.
`
`color temperature A precise measure of the hue of a
`given source of light stated as the temperature to
`which a black body would have to be heated in order
`to display the same color.
`Color
`temperature is
`expressed in degrees Kelvin (°K).
`
` am, the process of
`1, green, and blue
`ombine to make a
`
`
`
`color value The three numbers specifying a given
`color. See pixel value.
`
`column (1) One of two or more vertical arrangements
`of
`lines, positioned side by side on a page or
`screen.
`(T)
`(2) A vertical arrangement of characters
`or other expressions.
`(A)
`(3) A character position
`within a print line or on a display. The positions are
`numbered from 1, by 1, starting at the leftmost Char-
`acter position and extending to the rightmost position.
`(4) In SQL, the vertical part of a table. A column has
`a name and a particular data type;
`for example, char-
`acter, decimal, or integer.
`(5) In COBOL, a character
`position within a print line. Columns are numbered
`consecutively from 1, starting at the leftmost character
`position of the print line and extending to the right—
`most position of the print line.
`(6) Contrast with row.
`(7) See card column, mark—sensing column, punch
`column.
`
`a test pattern com-
`following colors:
`.21, red, blue, black,
`:ss, contrast, color
`
` color model A technique for describing a color, See
`
`also cyan/magenta/yellow (CYA).
`
`
`
`
`
`color noise In video systems, random interference in
`the color portion of an image, caused by reduced color
`bandwidth or color subsampling and appearing as
`
`indows, an entry in
`streaks of incorrect color in the image.
`
`zalues based on red,
`
`: values are l6~bit,
`the
` color number In the IBM LinkWay product,
`sents
`the minimum
`number assigned to a given color in a color palette.
`d by the server to :
`The background color is color number 0. The rest of
`the colors are numbered sequentially, starting with l.
` ations, a device
`
`
`‘lor palette A set of colors that can be displayed on
`
`or video Signal.
`e screen at one time. This can be a standard set
`sed for all images or a set that can be customized for
` tpplicationss
`ach image.
`Synonymous with color
`lookup table
`a series are
`
`UT). See also standard palette, custom palette.
`
`
`
`column balancing The process of redistributing lines
`of text among a set of columns so that the amount of
`text in each column is as equal as possible.
`
`
`column binary (l) Pertaining to the binary represen-
`tation of data on cards in which the weights of punch
`positions
`are
`assigned along card
`columns. For
`example, each column in a 12—row card may be used
`to represent 12 consecutive bits. (A)
`Synonymous
`with Chinese binary.
`(2) Contrast with row binary.
`
`or ramp A progression of colors in a color map;
` that can display m
`xample, the full range of colors of the rainbow,
`produced by COmb‘:
`d into the color map. Most color ramps have
`.st with monoch
`a small number,
`if any, of discontinuities.
`See
`
`
`
`the AIX hope:
`i
`
`register An area in computer memory that
`0 eration t a
`
`nformation about color.
`,g gtel map data
`m the destination
`
`resolution In video systems, a measure of the
`1y adapter buffer
`ess of a color image.
`1 per pixel.
`
`
`
`
`
`
`
`column function In SQL, a process that calculates a
`value from a set of values and expresses it as a func-
`tion name followed by an argument enclosed in paren—
`theses.
`
`anner A device used for converting C010r
`hs and art to digital data for use in an audio
`velopment application.
`
`
`
`garation A negative used for making the
`print each separate color.
`
`
`
`

`

`
`
`column heading
`
`[116]
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`COM device Computer output microfilmer.
`
`(A)
`
`comic-strip oriented image (1) In micrographics, an
`image appearing on roll microfilm in such a manner
`that the top edge of the image is parallel to the long
`edge of
`the
`film. (A)
`(2) Contrast with due
`oriented image. See Figure 33.
`
`
`
`
` combined condition In COBOL. a condition 31
`the result of connecting two or more conditions:
`_ with order.
`the AND or the OR logical operator. Contrast.
`St a functlon «
`
`
`
`negated combined condition.
`geommand I
`
`combined dictation and transcription machineD
`tation equipment designed to record and to reprodu
`
`speech so that a written record can be produced. (T
`ids and respons
`combined file A data file that is USed as both an in
`quest from a te
`cration or the «
`.
`.
`.
`,
`_-
`A any :
`file and an output file. The output file contains on
`) In SN ’
`those fields described for the output file;
`H). request head
`
`.
`.
`i
`_
`'
`R1
`output record does not necessarily contain the same
`equest ugltgcg1’
`fields as the input record.
`‘
`ins a Pr
`’
`(session—control
`re
`combined head On dictation equipment, a device that
`Ya“? an ELL—Lg}
`combines the functions of any two or all three of the
`mmcamr m t eset
`following parts:
`a recording head, a playback head,
`Virtual route re
`.
`A
`.
`(
`and an erase head.
`(I)
`Synonym for read/write head.
`“715310” headel'
`‘
`
`combined station (I) In high level data link control L
`
`string from a sour
`
`the part of a data station that supports the
`(HDLC),
`ents a request for :
`combined control functions of the data link and that;
`nication, an instrut
`.
`.
`‘
`e and tr:
`generates commands and responses for transnnssron
`Of 2} tramn causec
`and
`interprets
`received
`commands
`and
`statlon.
`~
`
`station to execute
`responses. (I)
`(2) A data station that generates
`
`commands and responses for transmission over a data
`also response.
`(13
`link and inter
`
`prets received commands and responses.
`(3) Synonymous with balanced station.
`See also
`
`primary station, secondary station.
`
`
`
`
`
`
`
`
`Command (1) In
`architecture. an a
`
`taining the comp
`parameters aSSOCIE
`formed by an app1
`action request.
`
`command analyz
`program that pl‘0<
`essing includes v2
`to
`a
`command
`returning to the CG
`command area (
`which the user er
`screen of a 3790
`areas in the syst
`communication at
`some devices,
`the
`mode to a comm
`command area.
`Access architectu:
`the command enl
`field"
`command attent
`key that can bet
`figuresttuigeegutgcil;
`function (CF) key
`n
`.
`.
`
`
`
`1“
`
`column heading One or more words at the top of a
`column of information that identify the information in
`that column.
`
`column mark line In an XL compiler error message,
`the line that contains the l symbol
`to indicate the
`column of code where the error was detected.
`
`column separator A symbol on each side of a posi—
`tion of a field on a display. The symbol does not
`occupy a position on the display.
`
`a card~processing
`capability of
`column split The
`device to read or punch two parts of a card column
`independently.
`(I)
`
`COM Computer output microfilming. (A)
`
`comb In a magnetic disk unit, an assembly of access
`arms that moves as a unit.
`(T)
`
`combination A given number of different elements
`selected from a set without regard to the order in
`which the selected elements are arranged.
`(I)
`(A)
`Contrast with permutation.
`See forbidden combina—
`tion.
`
`circuit (1) A logic device whose
`combinational
`output values at any given instant depend only upon
`the input values at that
`time. (T)
`(2) Synonymous
`with combinatorial circuit.
`
`least one
`combinational gate A device having at
`output channel and zero or more input channels, all
`characterized by discrete states,
`such that at any
`instant the state of each output channel is completely
`determined by the states of the input channels at the
`same instant.
`(T)
`(A)
`combinational logic element (1) A device having at
`least one output channel and zero or more input chan—
`nelsnall characterized by discrete states, such that at
`any instant
`the state of each output channel
`is com-
`pletely determined by the states of the input channels
`at the same instant. (A)
`(2) Contrast with sequen-
`tial logic element.
`
`.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`i
`
`
`
`
`
`
`combination box In S
`.
`AA Advanced Common User
`Access architecture, a control that combines the capa—
`bilities of an entry field and a list box. The list box
`contains choices th
`at a user can scroll and select to
`b
`S
`.
`-
`I‘Op—down combination
`ee also list box.
`ox.
`c9mblnatorial
`circuit Synonym for
`combinational
`emu“-
`elfcilnllgnseg atllert In the NetView program, an alert that
`1
`e
`01
`a non-generic alert and a Generic alert in
`one network in
`b
`vector transport (NMVT).
`
`.
`
`.
`
`I
`
`to be ali ned to the left of a comma.
`
`Figure 33. Comic-Strip—Oriented Image
`comma alignment tab A tab that marks where text is
`g
`command (I) An order for an action to take place.
`schema language. the order or trigger for an action or
`(2) A control signal. (A)
`(A)
`(3) In a conceptual
`permissible action to take place. (A)
`(4) Loosely. a
`
`

`

`
`
`(5) Synony-
`logic operator. (A)
`mathematical or
`mous with order. (A)
`(6) A statement used to
`request a function of the system. A command consists
`of the command name abbreviation, which identifies
`the requested function, and its parameters.
`(7) In
`SDLC,
`a frame transmitted by a primary station.
`Asynchronous balanced mode stations send both com-
`mands and responses. Contrast with response.
`(8) A
`request
`from a terminal for the performance of an
`operation or the execution of a particular program.
`(9) In SNA, any field set
`in the transmission header
`(TH), request header (RH), and sometimes portions of
`a request unit (RU),
`that
`initiates an action or that
`begins a protocol;
`for example:
`(a) Bind Session
`(session—control
`request unit), a command that
`acti—
`vates an LU—LU session,
`(b) The change—direction
`indicator in the RH of the last RU of a chain, (c) The
`virtual route reset window indicator in an FID trans-
`mission header. See also VTAM operator command.
`(10) A request for system action.
`(11) A character
`string from a source external to a system that repres—
`ents a request for system action.
`(12) In data commu—
`nication, an instruction represented in the control field
`of a frame and transmitted by a primary or combined
`station.
`It causes the addressed secondary/combined
`station to execute a data link control function.
`See
`also response.
`(13) Deprecated term for instruction.
`
`command
`
`condition that-is
`3 conditions with
`r. Contrast With
`
`on machine Dic~
`and to reproduce
`e produced.
`(T)
`
`:d as both an input
`file contains only
`t file;
`that is, the
`contain the same
`
`ment, a device that
`or all three of the
`l, a playback head,
`for read/write head.
`
`el data link control
`in that supports the
`5 data link and that
`:es
`for transmission
`commands
`and
`.tion that generates
`smission over a data
`_
`iands and responses.
`gtation
`See also .
`
`.icrofilmer. (A)
`
`In micrographics, an
`a: Be::3:3CD
`3 w5 Cl}C:oD‘
`:f
`
`.
`.s parallel to t
`Contrast with Cine
`
`ed Image
`
`Command (1) In SAA Basic Common User Access
`architecture, an action that displays a pop-up con-
`taining the command area.
`(2) The typed name and
`parameters associated with an action that can be per-
`formed by an application. A command is one form of
`action request.
`
`command analyzer In System/38, an IBM—supplied
`program that processes commands. Command proc—
`sing includes validity checking, transferring control
`a
`command processing program (CPP),
`and
`turning to the caller of the command analyzer.
`
`mand area (1) An area of a display screen in
`oh the user enters commands, for example, on the
`yen of a 3790 display component, the first of four
`n the system control area, providing system
`unication and instructions for the operator. On
`devices,
`the user must change from a working
`o a command mode to place the cursor in the
`rid area.
`(2) In SAA Basic Common User
`architecture. the area on a panel that contains
`
`.
`
`e
`
`that marks Wher
`)mma.
`
`i
`an action
`
`.
`d' attention (CA) key In DDS, a keyboard
`can be. specified with the CA keyword to
`function specified by the keyword. Data is
`t
`d to the system. Contrast with command )‘ key.
`
`Command
`
`[117]
`
`command field prompt
`
`lan-
`schema
`command condition In a conceptual
`guage,
`the precondition,
`including synchronization
`aspects,
`that must be met before a permissible action
`may take place. (A)
`
`command control block (CCB) In the IBM Token—
`Ring Network, a specifically formatted information
`provided from the application program to the adapter
`support software to request an operation.
`
`the AS/4OO system and
`command definition In
`System/38, an object that contains the definition of a
`command,
`including the command name, parameter
`descriptions, and validity-checking information, and
`identifies
`the program that performs
`the function
`requested by the command.
`
`command definition statement In the AS/400 system
`and System/38,
`a
`source
`statement
`that defines
`keywords and parameter values, qualified names, ele-
`ments in a list, parameter requirements and interre-
`lationships,
`and
`prompt
`text
`for
`a
`command.
`Command definition statements are used to create a
`command language (CL) command.
`
`command display In System/36, a display thatallows
`an operator to display and send messages and use
`control commands and procedure commands to start
`and control jobs. Contrast with standby display. See
`also console display, subconsole display.
`
`command display station In System/36, a display
`station from which an operator can start and control
`jobs.
`A command display station can become an
`alternative system console, can be designated as a sub—
`console, and can also be used as a data display station.
`See also alternative system console, data display
`station, subconsole.
`
`command entry field In SAA Basic Common User
`Access architecture, an entry field in which a user
`types commands. See also command area.
`
`command facility The component of the NetView
`program that is a base for command processors that
`can monitor, control, automate, and improve the oper-
`ation of a network.
`
`command field (I) On a display screen, a part of a
`command area.
`(2) In DPCX, the first of four areas
`on the bottom line of a display during field-by-field
`operations.
`See also communication field, message
`field, mode field.
`
`command field prompt In SAA Basic Common User
`Access
`architecture,
`a
`field prompt
`showing the
`location of
`the command entry field in a panel
`(Command ===>).
`
`
`
`
`
`

`

` command file
`
`
`
`[118]
`
`Oo5Bm:so.
`
`
`
`
`
`'5‘:3
`
`_ prOfile
`command library can be concatenated to the 8y
`
`command library.
`
`command line (I) On a display screen, a display 1
`usually at
`the bottom of the screen,
`in which on"
`commands can be entered. See also floating comma;1
`and pI‘OCBSSOI
`line.
`(2) In SAA usage,
`deprecated term_
`flgillevel language
`
`command area.
`
`
`command file In AS/4OO RJE, a remote job input
`stream that can contain host system commands and job
`control
`language (JCL), data, and RJE control
`state—
`ments (READFILE or EOF). Contrast with data file.
`
`a
`transmitted by
`command frame (I) A frame
`primary station.
`(2) A frame transmitted by a com—
`bined station that contains the address of the other
`combined stations.
`
`a key~
`command function (CF) key (I) In DDS,
`board key that can be specified with the CF keyword
`to request
`the function specified by the keyword.
`Data is
`returned to the
`system.
`Contrast with
`command attention (CA) key.
`(2) In System/36, a
`key that is used with the command (CMD) function
`control key to request preassigned functions. At the
`system console, a keyboard key, called a CF key, that
`is used to request preassigned functions.
`
`command help In the ImagePlus Folder Application
`Facility, online help about
`the commands the users
`enter on the command line.
`
`command interpreter In the AIX operating system, a
`program that sends instructions to the kernel. See also
`shell.
`
`command key (1) Any key that causes a device to
`perform a predefined operation.
`(2) A key on a
`display station keyboard used to request a specific pro—
`grammed action.
`(3) On the keyboard of an IBM per—
`sonal computer, a key that causes the PC to perform a
`particular operation as opposed to a key used to enter
`data. See also typewriter key. The command keys are
`the alternate (Alt) key, Caps Lock key, control (Ctrl)
`key, cursor movement keys, delete (Del) key, End key,
`enter key, escape (Esc) key, function keys, Horne key,
`insert (Ins) key, Num Lock key, page down (PgDn)
`key, page up (PgUp) key, print screen (PrtSc) key,
`Scroll Lock (and Break) key, shift key, and tab key.
`(4) See alternate function key, character key, function
`key. program attention key, program function key.
`
`command key indicator In RPG, an indicator defined
`to correspond with the function keys
`to tell
`the
`program when one of the function keys is pressed.
`
`command language A set of procedural operators
`with a related syntax, used to indicate the functions to
`be performed by an operating system.
`(I)
`(A)
`Syn—
`onymous with control language.
`
`command level Pertaining to an operation performed
`for a particular command in a program. Contrast with
`program level.
`
`command library In TSO, a partitioned data set con-
`sisting of command processor programs.
`A user
`
`
`
`
`
`
`
`
`
`In the NetView program, a list
`command list
`
`commands and statements designed to perform a sp’
`
`cific function for the user. Command lists can
`written in REXX or in the NetView command list la
`
`bmmand Progrz,“
`'llows programmm
`than by writing sta’
`
`_‘ ng language-
`command mode (I) A state of a system or device In
`
`which the user can enter commands.
`(2) In TSO, the
`command Prompt
`entry mode immediately following LOGON, or fol-
`
`(‘9O 0‘(D ’U,— A
`OOBBp:D0..
`lowing completion of a command processor.
`In
`
` command mode, the system is ready to accept any
`
`(3) In DPCX, a
`command in the command libraries.
`‘: icommand/respons
`mode of operation in which a terminal operator can do ‘
`1 Carrier Interconne
`any operation in basic mode, issue additional operator-
`‘ function that allo
`commands,
`and
`execute
`command
`procedures
`commands in a car
`(PROCs).
`
`
`
`first
`command name The
`usually followed by operands.
`
`term in
`
`a
`
`command,
`
`the
`command phase In the network control program,
`portion of the system response field in a basic trans-
`mission unit that identifies the step to which a combi-
`nation command;
`for example, Write with Contact,
`has progressed.
`
`command privilege class See privilege class.
`
`command procedure (PROC) (1) In DPCX, a user-
`written set of commands that an operator can invoke
`by name. A command procedure consists of operator
`commands and PROC commands. See command list.
`(2) In TSO, a data set or a member of a partitioned
`data set containing TSO commands to be performed
`sequentially by the EXEC command.
`(3)
`In the
`NetView program,
`a command list,
`a
`command
`processor written in a high—level language (HLL), or a
`NetView pipeline.
`
`and
`analyzing,
`command processing The reading,
`performing of commands
`issued via a console or
`through an input stream.
`
`command processing program (CPP) In the AS/4OO
`system and System/38, a program that performs some
`validity checking and processes a command so that the
`requested function is performed.
`
`command processor (1) A problem program exe-
`cuted
`to perform an
`operation
`specified
`by
`a
`command.
`(2) In System/36, the part of the System
`
`i command retry I
`that causes a 09m
`an I/O interruptlol
`
`command scan
`command lme er
`CMS parameter li
`
`command state“
`used to issue CC
`input stream.
`
`command strinj
`character string t
`
`command subst
`the ability to cal
`value to another
`line within (gm
`command 01'
`0‘
`accents
`and ti
`including grave
`feature is often '
`
`command Vi)”
`system, the vrrt
`the command t
`command wind
`
`command Win
`system, a key (
`virtual terminal
`bination is A
`buttons on a 1“-
`See also comm
`
`
`
`

`

`1d processorMd.
`
`commit
`command profile
`
`Support Program Product that processes control com-
`mands and passes procedure commands and operation
`control
`language statements to the initiator.
`(3)
`In
`the NetView program, a module designed to perform a
`specific function for
`the user.
`Users can write
`command processors in assembler language or in a
`high—level
`language (HLL); command processors are
`invoked as commands.
`
`command profile See profile.
`
`command programming language A language that
`allows programming by the use of commands rather
`than by writing statements in a conventional program—
`ming language.
`
`command prompt A displayed character or string of
`characters
`that
`indicates
`that a user may enter a
`command to be processed.
`
`the Network
`In
`command/response application
`Carrier Interconnect Manager and Agent programs, a
`function that allows a NetView operator to execute
`commands in a carrier management system.
`
`the
`command word In the AIX operating system,
`name of the 16—bit units used for storing graphic prim—
`itive strings. The first command word determines the
`primitive type and sets the length of the string. Sub-
`sequent command words contain information in multi—
`ples of quid, or 4 bits of data.
`
`comment (1) In programming languages, a language
`construct for the inclusion of text in a program and
`having no impact on the execution of the program.
`Comments are used to explain certain aspects of the
`program.
`(I)
`(2) A statement used to document a
`program or file. Comments include information that
`may be helpful
`in running a job or
`reviewing an
`output
`listing.
`(3) In the C language, a token that
`consists of one or more lines, delimited by /* and *l.
`Comments can be written anywhere in the program.
`(4) In Pascal, a token consisting of characters on one
`or more lines, delimited by /* */,
`(i< *), or
`{
`}
`.
`Comments can be written anywhere in the program.
`(5) In SQL, source program information that
`is not
`translated by the compiler. The format of a comment
`is language specific.
`(6) Synonymous with computer
`program annotation, note, remark.
`
`command retry A channel and control unit procedure
`that causes a command to be retried without requiring
`an I/O interruption.
`
`comment-entry In COBOL, an entry in the Identifi-
`cation Division that may be any combination of char—
`acters from the character set of a computer.
`
`to the system
`
`, a display line
`in which only
`ating command
`ited
`term for
`
`gram, a list of
`perform a spe-
`nd lists can be
`)mmand list lan—
`
`.
`
`tem or device in
`(2) In TSO, the
`JOGON, or fol-
`processor.
`In
`to accept any
`(3) In DPCX, a
`ti operator can do
`dditional operator
`and
`procedures
`
`in
`
`a
`
`command,
`
`Introl program, the
`i in a basic trans-
`to which a combi—
`lrite with Contact,
`
`.lege class.
`
`. 1n DPCX, a user»
`an invok
`
`(3)
`nand.
`a
`comm
`list,
`anguage (HLL)’ 0
`
`(6) In IMS/VS, an
`
`command scan In CMS, a routine that scans the
`command line entered and converts it
`to a standard
`~ CMS parameter list.
`
`:ommand statement A job control statement that is
`sed to issue commands to the system through the
`
`mmand string In AS/4OO query management,
`aracter string that contains a query command.
`
`a
`
`mand substitution In the AIX operating system,
`ability to capture the output of any command as a
`e. to another command by placing that command
`thin (grave accents). The shell first runs the
`nd or commands enclosed within the grave
`and then replaces
`the whole
`expression,
`‘g grave accents, with their output.
`This
`is often used in assignment statements.
`
`terminal In the AIX operating
`d-virtual
`the Virtual terminal that becomes active when
`
`Window. hot key In the AIX operating
`combination that activates the command
`1. The command window hot key com~
`‘lt-Actlon on the keyboard,
`the two
`mouse, or button number 4 on a tablet.
`
`line In COBOL, a source program line
`comment
`represented by an asterisk (*) in the indicator area of
`the line and any characters from the character set of
`the computer in area A and area B of that line.
`
`comment statement A source language statement that
`has no effect other than to be reproduced on an output
`listing.
`
`of
`set A combination
`instruction
`commercial
`instructions of the standard instruction set and the
`decimal feature.
`
`Commission Internationale de l’Eclairage (CIE) An
`international committee that develops color standards.
`
`to ensure action on
`commit (1) In DPPX/DTMS,
`requests made by a program during its current scope
`of recovery to change resettable or recreatable data—
`bases and to execute transactions.
`(2) To end the
`current scope of recovery and begin a new one.
`(3)
`To make all changes permanent that were made to one
`or more database files
`since the last commit or
`rollback operation, and make the changed records
`available to other users.
`(4) In SQL, the process that
`allows data changed by one application or user to be
`used by other applications or users. When a commit
`operation occurs, the locks are released to allow other
`applications to use the changed data.
`(5) A service
`that performs commit actions.
`
`

`

` medium access control (MAC) sublayer
`
`[426]
`
`
`
`member (I) A partition of a partitioned data set-.-
`(2) In VSE,
`the smallest unit of data that can be
`stored in and retrieved from a sublibrary.
`See also
`library member.
`(3) A data object
`in a structure, a
`union, or a library.
`(4) In the AS/400 system and
`System/38, one of several different sets of data, each
`with the same format, within a database file. See also -
`source member.
`(5) Synonym for element.
`(6) See
`library member.
`
`(MAC) sublayer (1) In a‘
`medium access control
`local area network, the part of the data link layer that
`applies a medium access method. The MAC sublayer
`supports topology—dependent
`functions and uses the
`services of the physical layer to provide services to the
`logical
`link control sublayer.
`(T)
`(2) One of two
`sublayers of the ISO Open Systems Interconnection
`data link layer proposed for local area networks by the
`IEEE Project 802 Committee on Local Area Networks
`and the European Computer Manufacturers Associ—
`ation (ECMA).
`It provides functions that depend on
`the topology of the network and uses services of the
`physical
`layer to provide services to the logical
`link
`control (LLC) sublayer. The 081 data link layer cor—
`responds to the SNA data link control layer.
`
`medium attachment unit (I) In a data station on a
`local area network, a device used to couple the data
`terminal
`equipment
`to
`the
`transmission medium.
`(T)
`(2) See figure at attachment unit
`interface.
`(3) See also transceiver.
`
`megahertz (MHz) A unit of measure of frequency,
`megahertz : 1,000,000 hertz.
`
`_
`,
`,
`mega (M) Ten to the sixth power;
`decimal notation. When referring to storage capacity,
`two to the twentieth power;
`1,048,576 in decimal
`notation.
`
`member list display In System/38, a display that lists
`the names of the members in a file that can be
`selected for processing.
`
`prbcessor from V
`initiated.
`.(T
`ailable,
`logical1
`the operator.
`(‘
`ccess architecti
`alsplays a list
`‘choice in the m
`in the menu b:
`Additional pop—
`choices.
`(5) 5
`submenu, system
`Note:
`In CU/
`
`term. The end 1
`
`
`
`
`
`
`
`medium close-up (MCU) In video and film pro—
`duction, a camera shot closer than a medium shot but
`not as close as a standard close-up.
`
`medium dependent interface In a local area network,
`the material and electrical inteiface between the trans—
`mission medium and a medium attachment unit.
`(T)
`(A)
`
`an
`the Print Services Facility,
`medium map In
`internal object in a form definition that identifies the
`overlays to be used and defines page placement and
`modifications to the form.
`
`medium overlay Synonym for overlay.
`
`medium shot In multimedia applications, a camera
`angle that reveals more of the subject than a close—up
`but
`less
`than a wide shot, usually from face to
`waistline. Synonymous with mid—shot.
`
`medium speed Usually,
`between 600 bps and the
`facility.
`
`rate
`transmission
`data
`limit of a voice-grade
`
`and
`storage and real
`megabyte (1) For processor
`virtual memory, 230 or 1048576 bytes.
`(2) For disk
`storage capacity and transmission rates, 1000000
`bytes.
`
`megacycle See megahertz.
`
`(T)
`megaflops (l) Synonym for MFLOPS.
`(2) O