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OS/2 Help File | 1995-03-14 | 86KB | 2,405 lines

ΓòÉΓòÉΓòÉ 1. Glossary ΓòÉΓòÉΓòÉ

This glossary defines many of the terms used in this book. It includes terms
and definitions from the IBM Dictionary of Computing, as well as terms specific
to the OS/2 operating system and the Presentation Manager. It is not a complete
glossary for the entire OS/2 operating system; nor is it a complete dictionary
of computer terms.

Other primary sources for these definitions are:

   o  The American National Standard Dictionary for Information Systems, ANSI
      X3.172-1990, copyrighted 1990 by the American National Standards
      Institute, 11 West 42nd Street, New York, New York 10036. These
      definitions are identified by the symbol (A) after the definition.

   o  The Information Technology Vocabulary, developed by Subcommittee 1, Joint
      Technical Committee 1, of the International Organization for
      Standardization and the International Electrotechnical Commission
      (ISO/IEC JTC1/SC1). Definitions of published parts of this vocabulary are
      identified by the symbol (I) after the definition; definitions taken from
      draft international standards, committee drafts, and working papers being
      developed by ISO/IEC JTC1/SC1 are identified by the symbol (T) after the
      definition, indicating that final agreement has not yet been reached
      among the participating National Bodies of SC1.


ΓòÉΓòÉΓòÉ 1.1. Glossary Listing ΓòÉΓòÉΓòÉ

Select a starting letter of glossary terms:

 A    N
 B    O
 C    P
 D    Q
 E    R
 F    S
 G    T
 H    U
 I    V
 J    W
 K    X
 L    Y
 M    Z


ΓòÉΓòÉΓòÉ <hidden> Glossary - A ΓòÉΓòÉΓòÉ

 accelerator  -In SAA Common User Access architecture, a key or combination of
   keys that invokes an application-defined function.

 accelerator table  -A table used to define which key strokes are treated as
   accelerators and the commands they are translated into.

 access mode  -The manner in which an application gains access to a file it has
   opened. Examples of access modes are read-only, write-only, and read/write.

 access permission  -All access rights that a user has regarding an object. (I)

 action  -One of a set of defined tasks that a computer performs. Users request
   the application to perform an action in several ways, such as typing a
   command, pressing a function key, or selecting the action name from an
   action bar or menu.

 action bar  -In SAA Common User Access architecture, the area at the top of a
   window that contains choices that give a user access to actions available in
   that window.

 action point  -The current position on the screen at which the pointer is
   pointing. Contrast with hot spot and input focus.

 active program  -A program currently running on the computer.  An active
   program can be interactive (running and receiving input from the user) or
   noninteractive (running but not receiving input from the user). See also
   interactive program and noninteractive program.

 active window  -The window with which the user is currently interacting.

 address space  -(1) The range of addresses available to a program. (A)  (2)
   The area of virtual storage available for a particular job.

 alphanumeric video output  -Output to the logical video buffer when the video
   adapter is in text mode and the logical video buffer is addressed by an
   application as a rectangular array of character cells.

 American National Standard Code for Information Interchange  -The standard
   code, using a coded character set consisting of 7-bit coded characters (8
   bits including parity check), that is used for information interchange among
   data processing systems, data communication systems, and associated
   equipment. The ASCII set consists of control characters and graphic
   characters. (A)

   Note:  IBM has defined an extension to ASCII code (characters 128-255).

 anchor  -A window procedure that handles Presentation Manager* message
   conversions between an icon procedure and an application.

 anchor block  -An area of Presentation-Manager-internal resources to allocated
   process or thread that calls WinInitialize.

 anchor point  -A point in a window used by a program designer or by a window
   manager to position a subsequently appearing window.

 ANSI  -American National Standards Institute.

 APA  -All points addressable.

 API  -Application programming interface.

 application  -A collection of software components used to perform specific
   types of work on a computer; for example, a payroll application, an airline
   reservation application, a network application.

 application object  -In SAA Advanced Common User Access architecture, a form
   that an application provides for a user; for example, a spreadsheet form.
   Contrast with user object.

 application programming interface (API)  -A functional interface supplied by
   the operating system or by a separately orderable licensed program that
   allows an application program written in a high-level language to use
   specific data or functions of the operating system or the licensed program.

 application-modal  -Pertaining to a message box or dialog box for which
   processing must be completed before further interaction with any other
   window owned by the same application may take place.

 area  -In computer graphics, a filled shape such as a solid rectangle.

 ASCII  -American National Standard Code for Information Interchange.

 ASCIIZ  -A string of ASCII characters that is terminated with a byte
   containing the value 0.

 aspect ratio  -In computer graphics, the width-to-height ratio of an area,
   symbol, or shape.

 asynchronous (ASYNC)  -(1) Pertaining to two or more processes that do not
   depend upon the occurrence of specific events such as common timing
   signals. (T)  (2) Without regular time relationship;  unexpected or
   unpredictable with respect to the execution of program instructions. See
   also synchronous.

 atom  -A constant that represents a string. As soon as a string has been
   defined as an atom, the atom can be used in place of the string to save
   space. Strings are associated with their respective atoms in an atom table.
   See also integer atom.

 atom table  -A table used to relate atoms with the strings that they
   represent. Also in the table is the mechanism by which the presence of a
   string can be checked.

 atomic operation  -An operation that completes its work on an object before
   another operation can be performed on the same object.

 attribute  -A characteristic or property that can be controlled, usually to
   obtain a required appearance;  for example, the color of a line. See also
   graphics attributes and segment attributes.

 automatic link  -In Information Presentation Facility (IPF), a link that
   begins a chain reaction at the primary window. When the user selects the
   primary window, an automatic link is activated to display secondary windows.

 AVIO  -Advanced Video Input/Output.


ΓòÉΓòÉΓòÉ <hidden> Glossary - B ΓòÉΓòÉΓòÉ

 BВzier curve  -(1) A mathematical technique of specifying smooth continous
   lines and surfaces, which require a starting point and a finishing point
   with several intermediate points that influence or control the path of the
   linking curve. Named after Dr. P. BВzier. (2) (D of C) In the AIX Graphics
   Library, a cubic spline approximation to a set of four control points that
   passes through the first and fourth control points and that has a continuous
   slope where two spline segments meet. Named after Dr. P. BВzier.

 background  -(1) In multiprogramming, the conditions under which low-priority
   programs are executed. Contrast with foreground. (2) An active session that
   is not currently displayed on the screen.

 background color  -The color in which the background of a graphic primitive is
   drawn.

 background mix  -An attribute that determines how the background of a graphic
   primitive is combined with the existing color of the graphics presentation
   space. Contrast with mix.

 background program  -In multiprogramming, a program that executes with a low
   priority. Contrast with foreground program.

 bit map  -A representation in memory of the data displayed on an APA device,
   usually the screen.

 block  -(1) A string of data elements recorded or transmitted as a unit. The
   elements may be characters, words, or logical records. (T)  (2) To record
   data in a block. (3) A collection of contiguous records recorded as a unit.
   Blocks are separated by interblock gaps and each block may contain one or
   more records. (A)

 block device  -A storage device that performs I/O operations on blocks of data
   called sectors. Data on block devices can be randomly accessed. Block
   devices are designated by a drive letter (for example, C:).

 blocking mode  -A condition set by an application that determines when its
   threads might block. For example, an application might set the Pipemode
   parameter for the DosCreateNPipe function so that its threads perform I/O
   operations to the named pipe block when no data is available.

 border  -A visual indication (for example, a separator line or a background
   color) of the boundaries of a window.

 boundary determination  -An operation used to compute the size of the smallest
   rectangle that encloses a graphics object on the screen.

 breakpoint  -(1) A point in a computer program where execution may be halted.
   A breakpoint is usually at the beginning of an instruction where halts,
   caused by external intervention, are convenient for resuming
   execution. (T)  (2) A place in a program, specified by a command or a
   condition, where the system halts execution and gives control to the
   workstation user or to a specified program.

 broken pipe  -When all of the handles that access one end of a pipe have been
   closed.

 bucket  -One or more fields in which the result of an operation is kept.

 buffer  -(1) A portion of storage used to hold input or output data
   temporarily. (2) To allocate and schedule the use of buffers. (A)

 button  -A mechanism used to request or initiate an action. See also barrel
   buttons, bezel buttons, mouse button, push button, and radio button.

 byte pipe  -Pipes that handle data as byte streams. All unnamed pipes are byte
   pipes. Named pipes can be byte pipes or message pipes. See byte stream.

 byte stream  -Data that consists of an unbroken stream of bytes.


ΓòÉΓòÉΓòÉ <hidden> Glossary - C ΓòÉΓòÉΓòÉ

 cache  -A high-speed buffer storage that contains frequently accessed
   instructions and data; it is used to reduce access time.

 cached micro presentation space  -A presentation space from a
   Presentation-Manager-owned store of micro presentation spaces. It can be
   used for drawing to a window only, and must be returned to the store when
   the task is complete.

 CAD  -Computer-Aided Design.

 call  -(1) The action of bringing a computer program, a routine, or a
   subroutine into effect, usually by specifying the entry conditions and
   jumping to an entry point. (I)  (A)  (2) To transfer control to a procedure,
   program, routine, or subroutine.

 calling sequence  -A sequence of instructions together with any associated
   data necessary to execute a call. (T)

 Cancel  -An action that removes the current window or menu without processing
   it, and returns the previous window.

 cascaded menu  -In the OS/2 operating system, a menu that appears when the
   arrow to the right of a cascading choice is selected. It contains a set of
   choices that are related to the cascading choice. Cascaded menus are used to
   reduce the length of a menu. See also cascading choice.

 cascading choice  -In SAA Common User Access architecture, a choice in a menu
   that, when selected, produces a cascaded menu containing other choices.  An
   arrow () appears to the right of the cascading choice.

 CASE statement  -In PM programming, provides the body of a window procedure.
   There is usually one CASE statement for each message type supported by an
   application.

 CGA  -Color graphics adapter.

 chained list  -A list in which the data elements may be dispersed but in which
   each data element contains information for locating the
   next. (T)Synonymous with linked list.

 character  -A letter, digit, or other symbol.

 character box  -In computer graphics, the boundary that defines, in world
   coordinates, the horizontal and vertical space occupied by a single
   character from a character set. See also character mode. Contrast with
   character cell.

 character cell  -The physical, rectangular space in which any single character
   is displayed on a screen or printer device. Position is addressed by row and
   column coordinates. Contrast with character box.

 character code  -The means of addressing a character in a character set,
   sometimes called code point.

 character device  -A device that performs I/O operations on one character at a
   time. Because character devices view data as a stream of bytes,
   character-device data cannot be randomly accessed. Character devices include
   the keyboard, mouse, and printer, and are referred to by name.

 character mode  -A mode that, in conjunction with the font type, determines
   the extent to which graphics characters are affected by the character box,
   shear, and angle attributes.

 character set  -(1) An ordered set of unique representations called
   characters; for example, the 26 letters of English alphabet, Boolean 0 and
   1, the set of symbols in the Morse code, and the 128 ASCII
   characters. (A)  (2) All the valid characters for a programming language or
   for a computer system. (3) A group of characters used for a specific reason;
   for example, the set of characters a printer can print.

 check box  -In SAA Advanced Common User Access architecture, a square box with
   associated text that represents a choice. When a user selects a choice, an X
   appears in the check box to indicate that the choice is in effect. The user
   can clear the check box by selecting the choice again. Contrast with radio
   button.

 check mark  - (1) (D of C) In SAA Advanced Common User Access architecture, a
   symbol that shows that a choice is currently in effect. (2) The symbol that
   is used to indicate a selected item on a pull-down menu.

 child process  -In the OS/2 operating system, a process started by another
   process, which is called the parent process. Contrast with parent process.

 child window  -A window that appears within the border of its parent window
   (either a primary window or another child window). When the parent window is
   resized, moved, or destroyed, the child window also is resized, moved, or
   destroyed; however, the child window can be moved or resized independently
   from the parent window, within the boundaries of the parent window. Contrast
   with parent window.

 choice  -(1) An option that can be selected. The choice can be presented as
   text, as a symbol (number or letter), or as an icon (a pictorial symbol).
   (2) (D of C) In SAA Common User Access architecture, an item that a user can
   select.

 chord  -(1) To press more than one button on a pointing device while the
   pointer is within the limits that the user has specified for the operating
   environment. (2) (D of C) In graphics, a short line segment whose end points
   lie on a circle. Chords are a means for producing a circular image from
   straight lines. The higher the number of chords per circle, the smoother the
   circular image.

 class  -In object-oriented design or programming, a group of objects that
   share a common definition and that therefore share common properties,
   operations, and behavior. Members of the group are called instances of the
   class.

 class method  -In System Object Model, an action that can be performed on a
   class object. Synonymous with factory method.

 class object  -In System Object Model, the run-time implementation of a class.

 class style  -The set of properties that apply to every window in a window
   class.

 client  -(1) A functional unit that receives shared services from a
   server. (T)  (2) A user, as in a client process that uses a named pipe or
   queue that is created and owned by a server process.

 client area  -The part of the window, inside the border, that is below the
   menu bar. It is the user's work space, where a user types information and
   selects choices from selection fields.  In primary windows, it is where an
   application programmer presents the objects that a user works on.

 client program  -An application that creates and manipulates instances of
   classes.

 client window  -The window in which the application displays output and
   receives input. This window is located inside the frame window, under the
   window title bar and any menu bar, and within any scroll bars.

 clip limits  -The area of the paper that can be reached by a printer or
   plotter.

 clipboard  -In SAA Common User Access architecture, an area of computer
   memory, or storage, that temporarily holds data. Data in the clipboard is
   available to other applications.

 clipping  -In computer graphics, removing those parts of a display image that
   lie outside a given boundary. (I)  (A)

 clipping area  -The area in which the window can paint.

 clipping path  -A clipping boundary in world-coordinate space.

 clock tick  -The minimum unit of time that the system tracks. If the system
   timer currently counts at a rate of X Hz, the system tracks the time every
   1/X of a second. Also known as time tick.

 CLOCK$  -Character-device name reserved for the system clock.

 code page  -An assignment of graphic characters and control-function meanings
   to all code points.

 code point  -(1) Synonym for character code. (2) (D of C) A 1-byte code
   representing one of 256 potential characters.

 code segment  -An executable section of programming code within a load module.

 color dithering  -See dithering.

 color graphics adapter (CGA)  -An adapter that simultaneously provides four
   colors and is supported by all IBM Personal Computer and Personal System/2
   models.

 command  -The name and parameters associated with an action that a program can
   perform.

 command area  -An area composed of a command field prompt and a command entry
   field.

 command entry field  -An entry field in which users type commands.

 command line  -On a display screen, a display line, sometimes at the bottom of
   the screen, in which only commands can be entered.

 command mode  -A state of a system or device in which the user can enter
   commands.

 command prompt  -A field prompt showing the location of the command entry
   field in a panel.

 Common Programming Interface (CPI)  -Definitions of those application
   development languages and services that have, or are intended to have,
   implementations on and a high degree of commonality across the SAA
   environments. One of the three SAA architectural areas. See also Common User
   Access architecture.

 Common User Access (CUA) architecture  - Guidelines for the dialog between a
   human and a workstation or terminal. One of the three SAA architectural
   areas. See also Common Programming Interface.

 compile  -To translate a program written in a higher-level programming
   language into a machine language program.

 composite window  -A window composed of other windows (such as a frame window,
   frame-control windows, and a client window) that are kept together as a unit
   and that interact with each other.

 computer-aided design (CAD)  -The use of a computer to design or change a
   product, tool, or machine, such as using a computer for drafting or
   illustrating.

 COM1, COM2, COM3  -Character-device names reserved for serial ports 1 through
   3.

 CON  -Character-device name reserved for the console keyboard and screen.

 conditional cascaded menu  -A pull-down menu associated with a menu item that
   has a cascade mini-push button beside it in an object's pop-up menu. The
   conditional cascaded menu is displayed when the user selects the mini-push
   button.

 container  -In SAA Common User Access architecture, an object that holds other
   objects. A folder is an example of a container object. See also folder and
   object.

 contextual help  -In SAA Common User Access Architecture, help that gives
   specific information about the item the cursor is on. The help is contextual
   because it provides information about a specific item as it is currently
   being used. Contrast with extended help.

 contiguous  -Touching or joining at a common edge or boundary, for example, an
   unbroken consecutive series of storage locations.

 control  -In SAA Advanced Common User Access architecture, a component of the
   user interface that allows a user to select choices or type information; for
   example, a check box, an entry field, a radio button.

 control area  -A storage area used by a computer program to hold control information. (I)  (A)

 Control Panel  -In the Presentation Manager, a program used to set up user
   preferences that act globally across the system.

 Control Program  -(1) The basic functions of the operating system, including
   DOS emulation and the support for keyboard, mouse, and video input/output.
   (2) A computer program designed to schedule and to supervise the execution
   of programs of a computer system. (I)  (A)

 control window  -A window that is used as part of a composite window to
   perform simple input and output tasks. Radio buttons and check boxes are
   examples.

 control word  -An instruction within a document that identifies its parts or
   indicates how to format the document.

 coordinate space  -A two-dimensional set of points used to generate output on
   a video display of printer.

 Copy  -A choice that places onto the clipboard, a copy of what the user has
   selected. See also Cut and Paste.

 correlation  -The action of determining which element or object within a
   picture is at a given position on the display. This follows a pick
   operation.

 coverpage window  -A window in which the application's help information is
   displayed.

 CPI  -Common Programming Interface.

 critical extended attribute  -An extended attribute that is necessary for the
   correct operation of the system or a particular application.

 critical section  -(1) In programming languages, a part of an asynchronous
   procedure that cannot be executed simultaneously with a certain part of
   another asynchronous procedure. (I)

   Note:  Part of the other asynchronous procedure also is a critical section.
   (2) A section of code that is not reentrant; that is, code that can be
   executed by only one thread at a time.

 CUA architecture  -Common User Access architecture.

 current position  -In computer graphics, the position, in user coordinates,
   that becomes the starting point for the next graphics routine, if that
   routine does not explicitly specify a starting point.

 cursor  -A symbol displayed on the screen and associated with an input device.
   The cursor indicates where input from the device will be placed. Types of
   cursors include text cursors, graphics cursors, and selection cursors.
   Contrast with pointer and input focus.

 Cut  -In SAA Common User Access architecture, a choice that removes a selected
   object, or a part of an object, to the clipboard, usually compressing the
   space it occupied in a window. See also Copy and Paste.


ΓòÉΓòÉΓòÉ <hidden> Glossary - D ΓòÉΓòÉΓòÉ

 daisy chain  -A method of device interconnection for determining interrupt
   priority by connecting the interrupt sources serially.

 data segment  -A nonexecutable section of a program module; that is, a section
   of a program that contains data definitions.

 data structure  -The syntactic structure of symbolic expressions and their
   storage-allocation characteristics. (T)

 data transfer  -The movement of data from one object to another by way of the
   clipboard or by direct manipulation.

 DBCS  -Double-byte character set.

 DDE  -Dynamic data exchange.

 deadlock  -(1) Unresolved contention for the use of a resource. (2) An error
   condition in which processing cannot continue because each of two elements
   of the process is waiting for an action by, or a response from, the other.
   (3) An impasse that occurs when multiple processes are waiting for the
   availability of a resource that will not become available because it is
   being held by another process that is in a similar wait state.

 debug  -To detect, diagnose, and eliminate errors in programs. (T)

 decipoint  -In printing, one tenth of a point.  There are 72 points in an
   inch.

 default procedure  -A function provided by the Presentation Manager Interface
   that may be used to process standard messages from dialogs or windows.

 default value  -A value assumed when no value has been specified. Synonymous
   with assumed value. For example, in the graphics programming interface, the
   default line-type is `solid'.

 definition list  -A type of list that pairs a term and its description.

 delta  -An application-defined threshold, or number of container items, from
   either end of the list.

 descendant  -See child process.

 descriptive text  -Text used in addition to a field prompt to give more
   information about a field.

 Deselect all  -A choice that cancels the selection of all of the objects that
   have been selected in that window.

 Desktop Manager  -In the Presentation Manager, a window that displays a list
   of groups of programs, each of which can be started or stopped.

 desktop window  -The window, corresponding to the physical device, against
   which all other types of windows are established.

 detached process  -A background process that runs independent of the parent
   process.

 detent  -A point on a slider that represents an exact value to which a user
   can move the slider arm.

 device context  -A logical description of a data destination such as memory,
   metafile, display, printer, or plotter. See also direct device context,
   information device context, memory device context, metafile device context,
   queued device context, and screen device context.

 device driver  -A file that contains the code needed to attach and use a
   device such as a display, printer, or plotter.

 device space  -(1) Coordinate space in which graphics are assembled after all
   GPI transformations have been applied. Device space is defined in
   device-specific units. (2) (D of C) In computer graphics, a space defined by
   the complete set of addressable points of a display device. (A)

 dialog  -The interchange of information between a computer and its user
   through a sequence of requests by the user and the presentation of responses
   by the computer.

 dialog box  -In SAA Advanced Common User Access architecture, a movable
   window, fixed in size, containing controls that a user uses to provide
   information required by an application so that it can continue to process a
   user request. See also message box, primary window, secondary window. Also
   known as a pop-up window.

 Dialog Box Editor  -A WYSIWYG editor that creates dialog boxes for
   communicating with the application user.

 dialog item  -A component (for example, a menu or a button) of a dialog box.
   Dialog items are also used when creating dialog templates.

 dialog procedure  -A dialog window that is controlled by a window procedure.
   It is responsible for responding to all messages sent to the dialog window.

 dialog tag language  -A markup language used by the DTL compiler to create
   dialog objects.

 dialog template  -The definition of a dialog box, which contains details of
   its position, appearance, and window ID, and the window ID of each of its
   child windows.

 direct device context  -A logical description of a data destination that is a
   device other than the screen (for example, a printer or plotter), and where
   the output is not to go through the spooler. Its purpose is to satisfy
   queries. See also device context.

 direct manipulation  -The user's ability to interact with an object by using
   the mouse, typically by dragging an object around on the Desktop and
   dropping it on other objects.

 direct memory access (DMA)  -A technique for moving data directly between main
   storage and peripheral equipment without requiring processing of the data by
   the processing unit.(T)

 directory  -A type of file containing the names and controlling information
   for other files or other directories.

 display point  -Synonym for pel.

 dithering  -(1) The process used in color displays whereby every other pel is
   set to one color, and the intermediate pels are set to another. Together
   they produce the effect of a third color at normal viewing distances. This
   process can only be used on solid areas of color; it does not work, for
   example, on narrow lines. (2) (D of C ) In computer graphics, a technique of
   interleaving dark and light pixels so that the resulting image looks
   smoothly shaded when viewed from a distance.

 DMA  -Direct memory access.

 DOS Protect Mode Interface (DPMI)  -An interface between protect mode and real
   mode programs.

 double-byte character set (DBCS)  -A set of characters in which each character
   is represented by two bytes.  Languages such as Japanese, Chinese, and
   Korean, which contain more characters than can be represented by 256 code
   points, require double-byte character sets. Since each character requires
   two bytes, the entering, displaying, and printing of DBCS characters
   requires hardware and software that can support DBCS.

 doubleword  -A contiguous sequence of bits or characters that comprises two
   computer words and is capable of being addressed as a unit. (A)

 DPMI  -DOS Protect Mode Interface.

 drag  -In SAA Common User Access, to use a pointing device to move an object;
   for example, clicking on a window border, and dragging it to make the window
   larger.

 dragging  -(1) In computer graphics, moving an object on the display screen as
   if it were attached to the pointer. (2) (D of C) In computer graphics,
   moving one or more segments on a display surface by translating. (I)  (A)

 drawing chain  -See segment chain.

 drop  -To fix the position of an object that is being dragged, by releasing
   the select button of the pointing device.

 drop  -To fix the position of an object that is being dragged, by releasing
   the select button of the pointing device. See also drag.

 DTL  -Dialog tag language.

 dual-boot function  -A feature of the OS/2 operating system that allows the
   user to start DOS from within the operating system, or an OS/2 session from
   within DOS.

 duplex  -Pertaining to communication in which data can be sent and received at
   the same time. Synonymous with full duplex.

 dynamic data exchange (DDE)  -A message protocol used to communicate between
   applications that share data. The protocol uses shared memory as the means
   of exchanging data between applications.

 dynamic data formatting  -A formatting procedure that enables you to
   incorporate text, bit maps or metafiles in an IPF window at execution time.

 dynamic link library  -A collection of executable programming code and data
   that is bound to an application at load time or run time, rather than during
   linking. The programming code and data in a dynamic link library can be
   shared by several applications simultaneously.

 dynamic linking  -The process of resolving external references in a program
   module at load time or run time rather than during linking.

 dynamic segments  -Graphics segments drawn in exclusive-OR mix mode so that
   they can be moved from one screen position to another without affecting the
   rest of the displayed picture.

 dynamic storage  -(1) A device that stores data in a manner that permits the
   data to move or vary with time such that the specified data is not always
   available for recovery. (A)  (2) A storage in which the cells require
   repetitive application of control signals in order to retain stored data.
   Such repetitive application of the control signals is called a refresh
   operation. A dynamic storage may use static addressing or sensing
   circuits. (A)  (3) See also static storage.

 dynamic time slicing  -Varies the size of the time slice depending on system
   load and paging activity.

 dynamic-link module  -A module that is linked at load time or run time.


ΓòÉΓòÉΓòÉ <hidden> Glossary - E ΓòÉΓòÉΓòÉ

 EBCDIC  -Extended binary-coded decimal interchange code. A coded character set
   consisting of 8-bit coded characters (9 bits including parity check), used
   for information interchange among data processing systems, data
   communications systems, and associated equipment.

 edge-triggered  -Pertaining to an event semaphore that is posted then reset
   before a waiting thread gets a chance to run. The semaphore is considered to
   be posted for the rest of that thread's waiting period; the thread does not
   have to wait for the semaphore to be posted again.

 EGA  -Extended graphics adapter.

 element  -An entry in a graphics segment that comprises one or more graphics
   orders and that is addressed by the element pointer.

 EMS  -Expanded Memory Specification.

 encapsulation  -Hiding an object's implementation, that is, its private,
   internal data and methods. Private variables and methods are accessible only
   to the object that contains them.

 entry field  -In SAA Common User Access architecture, an area where a user
   types information. Its boundaries are usually indicated. See also selection
   field.

 entry panel  -A defined panel type containing one or more entry fields and
   protected information such as headings, prompts, and explanatory text.

 entry-field control  -The component of a user interface that provides the
   means by which the application receives data entered by the user in an entry
   field. When it has the input focus, the entry field displays a flashing
   pointer at the position where the next typed character will go.

 environment segment  -The list of environment variables and their values for a
   process.

 environment strings  -ASCII text strings that define the value of environment
   variables.

 environment variables  -Variables that describe the execution environment of a
   process. These variables are named by the operating system or by the
   application. Environment variables named by the operating system are PATH,
   DPATH, INCLUDE, INIT, LIB, PROMPT, and TEMP. The values of environment
   variables are defined by the user in the CONFIG.SYS file, or by using the
   SET command at the OS/2 command prompt.

 error message  -An indication that an error has been detected. (A)

 event semaphore  -A semaphore that enables a thread to signal a waiting thread
   or threads that an event has occurred or that a task has been completed. The
   waiting threads can then perform an action that is dependent on the
   completion of the signaled event.

 exception  -An abnormal condition such as an I/O error encountered in
   processing a data set or a file.

 exclusive system semaphore  -A system semaphore that can be modified only by
   threads within the same process.

 executable file  -(1) A file that contains programs or commands that perform
   operations or actions to be taken. (2) A collection of related data records
   that execute programs.

 exit  -To execute an instruction within a portion of a computer program in
   order to terminate the execution of that portion. Such portions of computer
   programs include loops, subroutines, modules, and so on. (T)  Repeated exit
   requests return the user to the point from which all functions provided to
   the system are accessible. Contrast with cancel.

 expanded memory specification (EMS)  -Enables DOS applications to access
   memory above the 1MB real mode addressing limit.

 extended attribute  -An additional piece of information about a file object,
   such as its data format or category. It consists of a name and a value. A
   file object may have more than one extended attribute associated with it.

 extended help  -In SAA Common User Access architecture, a help action that
   provides information about the contents of the application window from which
   a user requested help. Contrast with contextual help.

 extended-choice selection  -A mode that allows the user to select more than
   one item from a window. Not all windows allow extended choice selection.
   Contrast with multiple-choice selection.

 extent  -Continuous space on a disk or diskette that is occupied by or
   reserved for a particular data set, data space, or file.

 external link  -In Information Presentation Facility, a link that connects
   external online document files.


ΓòÉΓòÉΓòÉ <hidden> Glossary - F ΓòÉΓòÉΓòÉ

 family-mode application  -An application program that can run in the OS/2
   environment and in the DOS environment; however, it cannot take advantage of
   many of the OS/2-mode facilities, such as multitasking, interprocess
   communication, and dynamic linking.

 FAT  -File allocation table.

 FEA  -Full extended attribute.

 field-level help  -Information specific to the field on which the cursor is
   positioned. This help function is "contextual" because it provides
   information about a specific item as it is currently used; the information
   is dependent upon the context within the work session.

 FIFO  -First-in-first-out. (A)

 file  -A named set of records stored or processed as a unit. (T)

 file allocation table (FAT)  -In IBM personal computers, a table used by the
   operating system to allocate space on a disk for a file, and to locate and
   chain together parts of the file that may be scattered on different sectors
   so that the file can be used in a random or sequential manner.

 file attribute  -Any of the attributes that describe the characteristics of a
   file.

 File Manager  -In the Presentation Manager, a program that displays
   directories and files, and allows various actions on them.

 file specification  -The full identifier for a file, which includes its drive
   designation, path, file name, and extension.

 file system  -The combination of software and hardware that supports storing
   information on a storage device.

 file system driver (FSD)  -A program that manages file I\O and controls the
   format of information on the storage media.

 fillet  -A curve that is tangential to the end points of two adjoining lines.
   See also polyfillet.

 filtering  -An application process that changes the order of data in a queue.

 first-in-first-out (FIFO)  -A queuing technique in which the next item to be
   retrieved is the item that has been in the queue for the longest time. (A)

 flag  -(1) An indicator or parameter that shows the setting of a switch. (2) A
   character that signals the occurrence of some condition, such as the end of
   a word. (A)  (3) (D of C) A characteristic of a file or directory that
   enables it to be used in certain ways. See also archive flag, hidden flag,
   and read-only flag.

 focus  -See input focus.

 folder  -A container used to organize objects.

 font  -A particular size and style of typeface that contains definitions of
   character sets, marker sets, and pattern sets.

 Font Editor  -A utility program provided with the IBM Developers Toolkit that
   enables the design and creation of new fonts.

 foreground program  -(1) The program with which the user is currently
   interacting. Also known as interactive program. Contrast with background
   program. (2) (D of C) In multiprogramming,  a high-priority program.

 frame  -The part of a window that can contain several different visual
   elements specified by the application, but drawn and controlled by the
   Presentation Manager. The frame encloses the client area.

 frame styles  -Standard window layouts provided by the Presentation Manager.

 FSD  -File system driver.

 full-duplex  -Synonym for duplex.

 full-screen application  -An application that has complete control of the
   screen.

 function  -(1) In a programming language, a block, with or without formal
   parameters, whose execution is invoked by means of a call. (2) A set of
   related control statements that cause one or more programs to be performed.

 function key  -A key that causes a specified sequence of operations to be
   performed when it is pressed, for example, F1 and Alt-K.

 function key area  -The area at the bottom of a window that contains function
   key assignments such as F1=Help.


ΓòÉΓòÉΓòÉ <hidden> Glossary - G ΓòÉΓòÉΓòÉ

 GDT  -Global Descriptor Table.

 general protection fault  -An exception condition that occurs when a process
   attempts to use storage or a module that has some level of protection
   assigned to it, such as I/O privilege level. See also IOPL code segment.

 Global Descriptor Table (GDT)  -A table that defines code and data segments
   available to all tasks in an application.

 global dynamic-link module  -A dynamic-link module that can be shared by all
   processes in the system that refer to the module name.

 global file-name character  -Either a question mark (?) or an asterisk (*)
   used as a variable in a file name or file name extension when referring to a
   particular file or group of files.

 glyph  -A graphic symbol whose appearance conveys information.

 GPI  -Graphics programming interface.

 graphic primitive  -In computer graphics, a basic element, such as an arc or a
   line, that is not made up of smaller parts and that is used to create
   diagrams and pictures. See also graphics segment.

 graphics  -(1) A picture defined in terms of graphic primitives and graphics
   attributes. (2) (D of C) The making of charts and pictures. (3) Pertaining
   to charts, tables, and their creation. (4) See computer graphics, coordinate
   graphics, fixed-image graphics, interactive graphics, passive graphics,
   raster graphics.

 graphics attributes  -Attributes that apply to graphic primitives. Examples
   are color, line type, and shading-pattern definition. See also segment
   attributes.

 graphics field  -The clipping boundary that defines the visible part of the
   presentation-page contents.

 graphics mode  -One of several states of a display. The mode determines the
   resolution and color content of the screen.

 graphics model space  -The conceptual coordinate space in which a picture is
   constructed after any model transforms have been applied. Also known as
   model space.

 Graphics programming interface  -The formally defined programming language
   that is between an IBM graphics program and the user of the program.

 graphics segment  -A sequence of related graphic primitives and graphics
   attributes. See also graphic primitive.

 graying  -The indication that a choice on a pull-down is unavailable.

 group  -A collection of logically connected controls. For example, the buttons
   controlling paper size for a printer could be called a group. See also
   program group.


ΓòÉΓòÉΓòÉ <hidden> Glossary - H ΓòÉΓòÉΓòÉ

 handle  -(1) An identifier that represents an object, such as a device or
   window, to the Presentation Interface. (2) (D of C) In the Advanced DOS and
   OS/2 operating systems, a binary value created by the system that identifies
   a drive, directory, and file so that the file can be found and opened.

 hard error  -An error condition on a network that requires either that the
   system be reconfigured or that the source of the error be removed before the
   system can resume reliable operation.

 header  -(1) System-defined control information that precedes user data. (2)
   The portion of a message that contains control information for the message,
   such as one or more destination fields, name of the originating station,
   input sequence number, character string indicating the type of message, and
   priority level for the message.

 heading tags  -A document element that enables information to be displayed in
   windows, and that controls entries in the contents window controls placement
   of push buttons in a window, and defines the shape and size of windows.

 heap  -An area of free storage available for dynamic allocation by an
   application. Its size varies according to the storage requirements of the
   application.

 help function  -(1) A function that provides information about a specific
   field, an application panel, or information about the help facility. (2) (D
   of C) One or more display images that describe how to use application
   software or how to do a system operation.

 Help index  -In SAA Common User Access architecture, a help action that
   provides an index of the help information available for an application.

 help panel  -A panel with information to assist users that is displayed in
   response to a help request from the user.

 help window  -A Common-User-Access-defined secondary window that displays
   information when the user requests help.

 hidden file  -An operating system file that is not displayed by a directory
   listing.

 hide button  -In the OS/2 operating system, a small, square button located in
   the right-hand corner of the title bar of a window that, when selected,
   removes from the screen all the windows associated with that window.
   Contrast with maximize button. See also restore button.

 hierarchical inheritance  -The relationship between parent and child classes.
   An object that is lower in the inheritance hierarchy than another object,
   inherits all the characteristics and behaviors of the objects above it in
   the hierarchy.

 hierarchy  -A tree of segments beginning with the root segment and proceeding
   downward to dependent segment types.

 high-performance file system (HPFS)  -In the OS/2 operating system, an
   installable file system that uses high-speed buffer storage, known as a
   cache, to provide fast access to large disk volumes. The file system also
   supports the coexistence of multiple, active file systems on a single
   personal computer, with the capability of multiple and different storage
   devices. File names used with the HPFS can have as many as 254 characters.

 hit testing  -The means of identifying which window is associated with which
   input device event.

 hook  -A point in a system-defined function where an application can supply
   additional code that the system processes as though it were part of the
   function.

 hook chain  -A sequence of hook procedures that are "chained" together so that
   each event is passed, in turn, to each procedure in the chain.

 hot spot  -The part of the pointer that must touch an object before it can be
   selected. This is usually the tip of the pointer. Contrast with action
   point.

 HPFS  -high-performance file system.

 hypergraphic link  -A connection between one piece of information and another
   through the use of graphics.

 hypertext  -A way of presenting information online with connections between
   one piece of information and another, called hypertext links. See also
   hypertext link.

 hypertext link  -A connection between one piece of information and another.


ΓòÉΓòÉΓòÉ <hidden> Glossary - I ΓòÉΓòÉΓòÉ

 I/O operation  -An input operation to, or output operation from a device
   attached to a computer.

 I-beam pointer  -A pointer that indicates an area, such as an entry field in
   which text can be edited.

 icon  -In SAA Advanced Common User Access architecture, a graphical
   representation of an object, consisting of an image, image background, and a
   label. Icons can represent items (such as a document file) that the user
   wants to work on, and actions that the user wants to perform. In the
   Presentation Manager, icons are used for data objects, system actions, and
   minimized programs.

 icon area  -In the Presentation Manager, the area at the bottom of the screen
   that is normally used to display the icons for minimized programs.

 Icon Editor  -The Presentation Manager-provided tool for creating icons.

 IDL  -Interface Definition Language.

 image font  -A set of symbols, each of which is described in a rectangular
   array of pels. Some of the pels in the array are set to produce the image of
   one of the symbols. Contrast with outline font.

 implied metaclass  -Subclassing the metaclass of a parent class without a
   separate CSC for the resultant metaclass.

 indirect manipulation  -Interaction with an object through choices and
   controls.

 information device context  -A logical description of a data destination other
   than the screen (for example, a printer or plotter), but where no output
   will occur. Its purpose is to satisfy queries. See also device context.

 information panel  -A defined panel type characterized by a body containing
   only protected information.

 Information Presentation Facility (IPF)  -A facility provided by the OS/2
   operating system, by which application developers can produce online
   documentation and context-sensitive online help panels for their
   applications.

 inheritance  -The derivation of new (child) classes from existing (parent)
   classes. The new class inherits all the data and methods of the parent class
   without having to redefine them.

 input focus  -(1) The area of a window where user interaction is possible
   using an input device, such as a mouse or the keyboard. (2) The position in
   the active window where a user's normal interaction with the keyboard will
   appear.

 input router  -An internal OS/2 process that removes messages from the system
   queue.

 input/output control  -A device-specific command that requests a function of a
   device driver.

 installable file system (IFS)  -A file system in which software is installed
   when the operating system is started.

 instance  -A single occurrence of an object class that has a particular
   behavior.

 instruction pointer  -In system/38, a pointer that provides addressability for
   a machine interface instruction in a program.

 integer atom  -An atom that represents a predefined system constant and
   carries no storage overhead. For example, names of window classes provided
   by Presentation Manager are expressed as integer atoms.

 interactive graphics  -Graphics that can be moved or manipulated by a user at
   a terminal.

 interactive program  -(1) A program that is running (active) and is ready to
   receive (or is receiving) input from a user. (2) A running program that can
   receive input from the keyboard or another input device. Compare with active
   program and contrast with noninteractive program.

   Also known as a foreground program.

 interchange file  -A file containing data that can be sent from one
   Presentation Manager interface application to another.

 Interface Definition Language (IDL)  -Language-neutral interface specification
   for a SOM class.

 interpreter  -A program that translates and executes each instruction of a
   high-level programming language before it translates and executes.

 interprocess communication (IPC)  -In the OS/2 operating system, the exchange
   of information between processes or threads through semaphores, pipes,
   queues, and shared memory.

 interval timer  -(1) A timer that provides program interruptions on a
   program-controlled basis. (2) An electronic counter that counts intervals of
   time under program control.

 IOCtl  -Input/output control.

 IOPL  -Input/output privilege level.

 IOPL code segment  -An IOPL executable section of programming code that
   enables an application to directly manipulate hardware interrupts and ports
   without replacing the device driver. See also privilege level.

 IPC  -Interprocess communication.

 IPF  -Information Presentation Facility.

 IPF compiler  -A text compiler that interpret tags in a source file and
   converts the information into the specified format.

 IPF tag language  -A markup language that provides the instructions for
   displaying online information.

 item  -A data object that can be passed in a DDE transaction.


ΓòÉΓòÉΓòÉ <hidden> Glossary - J ΓòÉΓòÉΓòÉ

 journal  -A special-purpose file that is used to record changes made in the
   system.


ΓòÉΓòÉΓòÉ <hidden> Glossary - K ΓòÉΓòÉΓòÉ

 Kanji  -A graphic character set used in Japanese ideographic alphabets.

 KBD$  -Character-device name reserved for the keyboard.

 kernel  -The part of an operating system that performs basic functions, such
   as allocating hardware resources.

 kerning  -The design of graphics characters so that their character boxes
   overlap. Used to space text proportionally.

 keyboard accelerator  -A keystroke that generates a command message for an
   application.

 keyboard augmentation  -A function that enables a user to press a keyboard key
   while pressing a mouse button.

 keyboard focus  -A temporary attribute of a window. The window that has a
   keyboard focus receives all keyboard input until the focus changes to a
   different window.

 Keys help  -In SAA Common User Access architecture, a help action that
   provides a listing of the application keys and their assigned functions.


ΓòÉΓòÉΓòÉ <hidden> Glossary - L ΓòÉΓòÉΓòÉ

 label  -In a graphics segment, an identifier of one or more elements that is
   used when editing the segment.

 LAN  -local area network.

 language support procedure  -A function provided by the Presentation Manager
   Interface for applications that do not, or cannot (as in the case of COBOL
   and FORTRAN programs), provide their own dialog or window procedures.

 lazy drag  -See pickup and drop.

 lazy drag set  -See pickup set.

 LDT  -In the OS/2 operating system, Local Descriptor Table.

 LIFO stack  -A stack from which data is retrieved in last-in, first-out order.

 linear address  -A unique value that identifies the memory object.

 linked list  -Synonym for chained list.

 list box  -In SAA Advanced Common User Access architecture, a control that
   contains scrollable choices from which a user can select one choice.

   Note:  In CUA architecture, this is a programmer term. The end user term is
   selection list.

 list button  -A button labeled with an underlined down-arrow that presents a
   list of valid objects or choices that can be selected for that field.

 list panel  -A defined panel type that displays a list of items from which
   users can select one or more choices and then specify one or more actions to
   work on those choices.

 load time  -The point in time at which a program module is loaded into main
   storage for execution.

 load-on-call  -A function of a linkage editor that allows selected segments of
   the module to be disk resident while other segments are executing. Disk
   resident segments are loaded for execution and given control when any entry
   point that they contain is called.

 local area network (LAN)  -(1) A computer network located on a user's premises
   within a limited geographical area. Communication within a local area
   network is not subject to external regulations;  however, communication
   across the LAN boundary may be subject to some form of regulation. (T)

   Note:  A LAN does not use store and forward techniques. (2) A network
   inwhich a set of devices are connected to one another for communication and
   that can be connected to a larger network.

 Local Descriptor Table (LDT)  -Defines code and data segments specific to a
   single task.

 lock  -A serialization mechanism by means of which a resource is restricted
   for use by the holder of the lock.

 logical storage device  -A device that the user can map to a physical (actual)
   device.

 LPT1, LPT2, LPT3  -Character-device names reserved for parallel printers 1
   through 3.


ΓòÉΓòÉΓòÉ <hidden> Glossary - M ΓòÉΓòÉΓòÉ

 main window  -The window that is positioned relative to the desktop window.

 manipulation button  -The button on a pointing device a user presses to
   directly manipulate an object.

 map  -(1) A set of values having a defined correspondence with the quantities
   or values of another set. (I)  (A)  (2) To establish a set of values having
   a defined correspondence with the quantities or values of another set. (I)

 marker box  -In computer graphics, the boundary that defines, in world
   coordinates, the horizontal and vertical space occupied by a single marker
   from a marker set.

 marker symbol  -A symbol centered on a point. Graphs and charts can use marker
   symbols to indicate the plotted points.

 marquee box  -The rectangle that appears during a selection technique in which
   a user selects objects by drawing a box around them with a pointing device.

 Master Help Index  -In the OS/2 operating system, an alphabetic list of help
   topics related to using the operating system.

 maximize  -To enlarge a window to its largest possible size.

 media window  -The part of the physical device (display, printer, or plotter)
   on which a picture is presented.

 memory block  -Part memory within a heap.

 memory device context  -A logical description of a data destination that is a
   memory bit map. See also device context.

 memory management  -A feature of the operating system for allocating, sharing,
   and freeing main storage.

 memory object  -Logical unit of memory requested by an application, which
   forms the granular unit of memory manipulation from the application
   viewpoint.

 menu  -In SAA Advanced Common User Access architecture, an extension of the
   menu bar that displays a list of choices available for a selected choice in
   the menu bar. After a user selects a choice in menu bar, the corresponding
   menu appears. Additional pop-up windows can appear from menu choices.

 menu bar  -In SAA Advanced Common User Access architecture, the area near the
   top of a window, below the title bar and above the rest of the window, that
   contains choices that provide access to other menus.

 menu button  -The button on a pointing device that a user presses to view a
   pop-up menu associated with an object.

 message  -(1) In the Presentation Manager, a packet of data used for
   communication between the Presentation Manager interface and Presentation
   Manager applications (2) In a user interface, information not requested by
   users but presented to users by the computer in response to a user action or
   internal process.

 message box  -(1) A dialog window predefined by the system and used as a
   simple interface for applications, without the necessity of creating
   dialog-template resources or dialog procedures. (2) (D of C) In SAA Advanced
   Common User Access architecture, a type of window that shows messages to
   users. See also dialog box, primary window, secondary window.

 message filter  -The means of selecting which messages from a specific window
   will be handled by the application.

 message queue  -A sequenced collection of messages to be read by the
   application.

 message stream mode  -A method of operation in which data is treated as a
   stream of messages.  Contrast with  byte stream.

 metacharacter  -See global file-name character.

 metaclass  -The conjunction of an object and its class information; that is,
   the information pertaining to the class as a whole, rather than to a single
   instance of the class. Each class is itself an object, which is an instance
   of the metaclass.

 metafile  -A file containing a series of attributes that set color, shape and
   size, usually of a picture or a drawing. Using a program that can interpret
   these attributes, a user can view the assembled image.

 metafile device context  -A logical description of a data destination that is
   a metafile, which is used for graphics interchange. See also device context.

 metalanguage  -A language used to specify another language. For example, data
   types can be described using a metalanguage so as to make the descriptions
   independent of any one computer language.

 method  -A function that defines a behavior for a class or object.

 method override  -The replacement, by a child class, of the implementation of
   a method inherited from a parent and an ancestor class.

 mickey  -A unit of measurement for physical mouse motion whose value depends
   on the mouse device driver currently loaded.

 micro presentation space  -A graphics presentation space in which a restricted
   set of the GPI function calls is available.

 minimize  -To remove from the screen all windows associated with an
   application and replace them with an icon that represents the application.

 mix  -An attribute that determines how the foreground of a graphic primitive
   is combined with the existing color of graphics output. Also known as
   foreground mix. Contrast with background mix.

 mixed character string  -A string containing a mixture of one-byte and Kanji
   or Hangeul (two-byte) characters.

 mnemonic  -(1) A method of selecting an item on a pull-down by means of typing
   the highlighted letter in the menu item. (2) (D of C) In SAA Advanced Common
   User Access architecture, usually a single character, within the text of a
   choice, identified by an underscore beneath the character. If all characters
   in a choice already serve as mnemonics for other choices, another character,
   placed in parentheses immediately following the choice, can be used. When a
   user types the mnemonic for a choice, the choice is either selected or the
   cursor is moved to that choice.

 modal dialog box  -In SAA Advanced Common User Access architecture, a type of
   movable window, fixed in size, that requires a user to enter information
   before continuing to work in the application window from which it was
   displayed. Contrast with modeless dialog box. Also known as a serial dialog
   box. Contrast with parallel dialog box.

   Note:  In CUA architecture, this is a programmer term. The end user term is
   pop-up window.

 model space  -See graphics model space.

 modeless dialog box  -In SAA Advanced Common User Access architecture, a type
   of movable window, fixed in size, that allows users to continue their dialog
   with the application without entering information in the dialog box. Also
   known as a parallel dialog box. Contrast with modal dialog box.

   Note:  In CUA architecture, this is a programmer term. The end user term is
   pop-up window.

 module definition file  -A file that describes the code segments within a load
   module. For example, it indicates whether a code segment is loadable before
   module execution begins (preload), or loadable only when referred to at run
   time (load-on-call).

 mouse  -In SAA usage, a device that a user moves on a flat surface to position
   a pointer on the screen. It allows a user to select a choice o function to
   be performed or to perform operations on the screen, such as dragging or
   drawing lines from one position to another.

 MOUSE$  -Character-device name reserved for a mouse.

 multiple-choice selection  -In SAA Basic Common User Access architecture, a
   type of field from which a user can select one or more choices or select
   none. See also check box. Contrast with extended-choice selection.

 multiple-line entry field  -In SAA Advanced Common User Access architecture, a
   control into which a user types more than one line of information. See also
   single-line entry field.

 multitasking  -The concurrent processing of applications or parts of
   applications. A running application and its data are protected from other
   concurrently running applications.

 mutex semaphore  -(Mutual exclusion semaphore). A semaphore that enables
   threads to serialize their access to resources. Only the thread that
   currently owns the mutex semaphore can gain access to the resource, thus
   preventing one thread from interrupting operations being performed by
   another.

 muxwait semaphore  -(Multiple wait semaphore). A semaphore that enables a
   thread to wait either for multiple event semaphores to be posted or for
   multiple mutex semaphores to be released. Alternatively, a muxwait semaphore
   can be set to enable a thread to wait for any ONE of the event or mutex
   semaphores in the muxwait semaphore's list to be posted or released.


ΓòÉΓòÉΓòÉ <hidden> Glossary - N ΓòÉΓòÉΓòÉ

 named pipe  -A named buffer that provides client-to-server, server-to-client,
   or full duplex communication between unrelated processes. Contrast with
   unnamed pipe.

 national language support (NLS)  -The modification or conversion of a United
   States English product to conform to the requirements of another language or
   country. This can include the enabling or retrofitting of a product and the
   translation of nomenclature, MRI, or documentation of a product.

 nested list  -A list that is contained within another list.

 NLS  -national language support.

 non-8.3 file-name format  -A file-naming convention in which file names can
   consist of up to 255 characters. See also 8.3 file-name format.

 noncritical extended attribute  -An extended attribute that is not necessary
   for the function of an application.

 nondestructive read  -Reading that does not erase the data in the source
   location. (T)

 noninteractive program  -A running program that cannot receive input from the
   keyboard or other input device. Compare with active program, and contrast
   with interactive program.

 nonretained graphics  -Graphic primitives that are not remembered by the
   Presentation Manager interface when they have been drawn. Contrast with
   retained graphics.

 null character (NUL)  -(1) Character-device name reserved for a nonexistent
   (dummy) device. (2) (D of C) A control character that is used to accomplish
   media-fill or time-fill and that may be inserted into or removed from a
   sequence of characters without affecting the meaning of the sequence;
   however, the control of equipment or the format may be affected by this
   character. (I)  (A)

 null-terminated string  -A string of (n+1) characters where the (n+1)th
   character is the `null' character (0x00) Also known as `zero-terminated'
   string and 'ASCIIZ' string.


ΓòÉΓòÉΓòÉ <hidden> Glossary - O ΓòÉΓòÉΓòÉ

 object  -A set of data and actions that can be performed on that data.

 Object Interface Definition Language (OIDL)  -Specification language used in
   SOM Version 1 for defining classes. Replaced by Interface Definition
   Language (IDL).

 object window  -A window that does not have a parent but which might have
   child windows. An object window cannot be presented on a device.

 OIDL  -Object Interface Definition Language.

 open  -To start working with a file, directory, or other object.

 ordered list  -Vertical arrangements of items, with each item in the list
   preceded by a number or letter.

 outline font  -A set of symbols, each of which is created as a series of lines
   and curves.  Synonymous with vector font. Contrast with image font.

 output area  -An area of storage reserved for output. (A)

 owner window  -A window into which specific events that occur in another
   (owned) window are reported.

 ownership  -The determination of how windows communicate using messages.

 owning process  -The process that owns the resources that might be shared with
   other processes.


ΓòÉΓòÉΓòÉ <hidden> Glossary - P ΓòÉΓòÉΓòÉ

 page  -(1) A 4KB segment of contiguous physical memory. (2) (D of C) A defined
   unit of space on a storage medium.

 page viewport  -A boundary in device coordinates that defines the area of the
   output device in which graphics are to be displayed. The presentation-page
   contents are transformed automatically to the page viewport in device space.

 paint  -(1) The action of drawing or redrawing the contents of a window. (2)
   In computer graphics, to shade an area of a display image;  for example,
   with crosshatching or color.

 panel  -In SAA Basic Common User Access architecture, a particular arrangement
   of information that is presented in a window or pop-up. If some of the
   information is not visible, a user can scroll through the information.

 panel area  -An area within a panel that contains related information. The
   three major Common User Access-defined panel areas are the action bar, the
   function key area, and the panel body.

 panel area separator  -In SAA Basic Common User Access architecture, a solid,
   dashed, or blank line that provides a visual distinction between two
   adjacent areas of a panel.

 panel body  -The portion of a panel not occupied by the action bar, function
   key area, title or scroll bars. The panel body can contain protected
   information, selection fields, and entry fields. The layout and content of
   the panel body determine the panel type.

 panel body area  -See client area.

 panel definition  -A description of the contents and characteristics of a
   panel. A panel definition is the application developer's mechanism for
   predefining the format to be presented to users in a window.

 panel ID  -In SAA Basic Common User Access architecture, a panel identifier,
   located in the upper-left corner of a panel.  A user can choose whether to
   display the panel ID.

 panel title  -In SAA Basic Common User Access architecture, a particular
   arrangement of information that is presented in a window or pop-up. If some
   of the information is not visible, a user can scroll through the
   information.

 paper size  -The size of paper, defined in either standard U.S. or European
   names (for example, A, B, A4), and measured in inches or millimeters
   respectively.

 parallel dialog box  -See modeless dialog box.

 parameter list  -A list of values that provides a means of associating
   addressability of data defined in a called program with data in the calling
   program. It contains parameter names and the order in which they are to be
   associated in the calling and called program.

 parent process  -In the OS/2 operating system, a process that creates other
   processes. Contrast with child process.

 parent window  -In the OS/2 operating system, a window that creates a child
   window. The child window is drawn within the parent window. If the parent
   window is moved, resized, or destroyed, the child window also will be moved,
   resized, or destroyed. However, the child window can be moved and resized
   independently from the parent window, within the boundaries of the parent
   window. Contrast with child window.

 partition  -(1) A fixed-size division of storage. (2) On an IBM personal
   computer fixed disk, one of four possible storage areas of variable size;
   one may be accessed by DOS, and each of the others may be assigned to
   another operating system.

 Paste  -A choice in the Edit pull-down that a user selects to move the
   contents of the clipboard into a preselected location. See also Copy and
   Cut.

 path  -The route used to locate files; the storage location of a file. A fully
   qualified path lists the drive identifier, directory name, subdirectory name
   (if any), and file name with the associated extension.

 PDD  -Physical device driver.

 peeking  -An action taken by any thread in the process that owns the queue to
   examine queue elements without removing them.

 pel  -(1) The smallest area of a display screen capable of being addressed and
   switched between visible and invisible states. Synonym for display point,
   pixel, and picture element. (2) (D of C) Picture element.

 persistent object  -An object whose instance data and state are preserved
   between system shutdown and system startup.

 physical device driver (PDD)  -A system interface that handles hardware
   interrupts and supports a set of input and output functions.

 pick  -To select part of a displayed object using the pointer.

 pickup  -To add an object or set of objects to the pickup set.

 pickup and drop  -A drag operation that does not require the direct
   manipulation button to be pressed for the duration of the drag.

 pickup set  -The set of objects that have been picked up as part of a pickup
   and drop operation.

 picture chain  -See segment chain.

 picture element  -(1) Synonym for pel. (2) (D of C) In computer graphics, the
   smallest element of a display surface that can be independently assigned
   color and intensity. (T)  . (3) The area of the finest detail that can be
   reproduced effectively on the recording medium.

 PID  -Process identification.

 pipe  -(1) A named or unnamed buffer used to pass data between processes. A
   process reads from or writes to a pipe as if the pipe were a standard-input
   or standard-output file. See also named pipe and unnamed pipe. (2) (D of C)
   To direct data so that the output from one process becomes the input to
   another process. The standard output of one command can be connected to the
   standard input of another with the pipe operator (|).

 pixel  -(1) Synonym for pel. (2) (D of C) Picture element.

 plotter  -An output unit that directly produces a hardcopy record of data on a
   removable medium, in the form of a two-dimensional graphic representation. (T)

 PM  -Presentation Manager.

 pointer  -(1) The symbol displayed on the screen that is moved by a pointing
   device, such as a mouse. The pointer is used to point at items that users
   can select. Contrast with cursor. (2) A data element that indicates the
   location of another data element. (T)

 POINTER$  -Character-device name reserved for a pointer device (mouse screen
   support).

 pointing device  -In SAA Advanced Common User Access architecture, an
   instrument, such as a mouse, trackball, or joystick, used to move a pointer
   on the screen.

 pointings  -Pairs of x-y coordinates produced by an operator defining
   positions on a screen with a pointing device, such as a mouse.

 polyfillet  -A curve based on a sequence of lines. The curve is tangential to
   the end points of the first and last lines, and tangential also to the
   midpoints of all other lines. See also fillet.

 polygon  -One or more closed figures that can be drawn filled, outlined, or
   filled and outlined.

 polyline  -A sequence of adjoining lines.

 polymorphism  -The ability to have different implementations of the same
   method for two or more classes of objects.

 pop  -To retrieve an item from a last-in-first-out stack of items. Contrast
   with push.

 pop-up menu  -A menu that lists the actions that a user can perform on an
   object. The contents of the pop-up menu can vary depending on the context,
   or state, of the object.

 pop-up window  -(1) A window that appears on top of another window in a
   dialog. Each pop-up window must be completed before returning to the
   underlying window. (2) (D of C) In SAA Advanced Common User Access
   architecture, a movable window, fixed in size, in which a user provides
   information required by an application so that it can continue to process a
   user request.

 presentation drivers  -Special purpose I/O routines that handle field
   device-independent I/O requests from the PM and its applications.

 Presentation Manager (PM)  -The interface of the OS/2 operating system that
   presents, in windows a graphics-based interface to applications and files
   installed and running under the OS/2 operating system.

 presentation page  -The coordinate space in which a picture is assembled for
   display.

 presentation space (PS)  -(1) Contains the device-independent definition of a
   picture. (2) (D of C) The display space on a display device.

 primary window  -In SAA Common User Access architecture, the window in which
   the main interaction between the user and the application takes place. In a
   multiprogramming environment, each application starts in its own primary
   window. The primary window remains for the duration of the application,
   although the panel displayed will change as the user's dialog moves forward.
   See also secondary window.

 primitive  -In computer graphics, one of several simple functions for drawing
   on the screen, including, for example, the rectangle, line, ellipse,
   polygon, and so on.

 primitive attribute  -A specifiable characteristic of a graphic primitive. See
   graphics attributes.

 print job  -The result of sending a document or picture to be printed.

 Print Manager  -In the Presentation Manager, the part of the spooler that
   manages the spooling process. It also allows users to view print queues and
   to manipulate print jobs.

 privilege level  -A protection level imposed by the hardware architecture of
   the IBM personal computer.  There are four privilege levels (number 0
   through 3).  Only certain types of programs are allowed to execute at each
   privilege level.  See also IOPL code segment.

 procedure call  -In programming languages, a language construct for invoking
   execution of a procedure.

 process  -An instance of an executing application and the resources it is
   using.

 program  -A sequence of instructions that a computer can interpret and
   execute.

 program details  -Information about a program that is specified in the Program
   Manager window and is used when the program is started.

 program group  -In the Presentation Manager, several programs that can be
   acted upon as a single entity.

 program name  -The full file specification of a program. Contrast with program
   title.

 program title  -The name of a program as it is listed in the Program Manager
   window. Contrast with program name.

 prompt  -A displayed symbol or message that requests input from the user or
   gives operational information; for example, on the display screen of an IBM
   personal computer, the DOS A> prompt. The user must respond to the prompt in
   order to proceed.

 protect mode  -A method of program operation that limits or prevents access to
   certain instructions or areas of storage. Contrast with real mode.

 protocol  -A set of semantic and syntactic rules that determines the behavior
   of functional units in achieving communication. (I)

 pseudocode  -An artificial language used to describe computer program
   algorithms without using the syntax of any particular programming language. (A)

 pull-down  -(1) An action bar extension that displays a list of choices
   available for a selected action bar choice. After users select an action bar
   choice, the pull-down appears with the list of choices. Additional pop-up
   windows may appear from pull-down choices to further extend the actions
   available to users. (2) (D of C) In SAA Common User Access architecture,
   pertaining to a choice in an action bar pull-down.

 push  -To add an item to a last-in-first-out stack of items. Contrast with
   pop.

 push button  -In SAA Advanced Common User Access architecture, a rectangle
   with text inside. Push buttons are used in windows for actions that occur
   immediately when the push button is selected.

 putback  -To remove an object or set of objects from the lazy drag set. This
   has the effect of undoing the pickup operation for those objects

 putdown  -To drop the objects in the lazy drag set on the target object.


ΓòÉΓòÉΓòÉ <hidden> Glossary - Q ΓòÉΓòÉΓòÉ

 queue  -(1) A linked list of elements waiting to be processed in FIFO order.
   For example, a queue may be a list of print jobs waiting to be printed. (2)
   (D of C) A line or list of items waiting to be processed; for example, work
   to be performed or messages to be displayed.

 queued device context  -A logical description of a data destination (for
   example, a printer or plotter) where the output is to go through the
   spooler. See also device context.


ΓòÉΓòÉΓòÉ <hidden> Glossary - R ΓòÉΓòÉΓòÉ

 radio button  -(1) A control window, shaped like a round button on the screen,
   that can be in a checked or unchecked state. It is used to select a single
   item from a list. Contrast with check box. (2) In SAA Advanced Common User
   Access architecture, a circle with text beside it. Radio buttons are
   combined to show a user a fixed set of choices from which only one can be
   selected. The circle is partially filled when a choice is selected.

 RAS  -Reliability, availability, and serviceability.

 raster  -(1) In computer graphics, a predetermined pattern of lines that
   provides uniform coverage of a display space. (T)  (2) The coordinate grid
   that divides the display area of a display device.  (A)

 read-only file  -A file that can be read from but not written to.

 real mode  -A method of program operation that does not limit or prevent
   access to any instructions or areas of storage.  The operating system loads
   the entire program into storage and gives the program access to all system
   resources. Contrast with protect mode.

 realize  -To cause the system to ensure, wherever possible, that the physical
   color table of a device is set to the closest possible match in the logical
   color table.

 recursive routine  -A routine that can call itself, or be called by another
   routine that was called by the recursive routine.

 reentrant  -The attribute of a program or routine that allows the same copy of
   the program or routine to be used concurrently by two or more tasks.

 reference phrase  -(1) A word or phrase that is emphasized in a
   device-dependent manner to inform the user that additional information for
   the word or phrase is available. (2) (D of C) In hypertext, text that is
   highlighted and preceded by a single-character input field used to signify
   the existence of a hypertext link.

 reference phrase help  -In SAA Common User Access architecture, highlighted
   words or phrases within help information that a user selects to get
   additional information.

 refresh  -To update a window, with changed information, to its current status.

 region  -A clipping boundary in device space.

 register  -A part of internal storage having a specified storage capacity and
   usually intended for a specific purpose. (T)

 remote file system  -A file-system driver that gains access to a remote system
   without a block device driver.

 resource  -The means of providing extra information used in the definition of
   a window. A resource can contain definitions of fonts, templates,
   accelerators, and mnemonics; the definitions are held in a resource file.

 resource file  -A file containing information used in the definition of a
   window. Definitions can be of fonts, templates, accelerators, and mnemonics.

 restore  -To return a window to its original size or position following a
   sizing or moving action.

 retained graphics  -Graphic primitives that are remembered by the Presentation
   Manager interface after they have been drawn. Contrast with nonretained
   graphics.

 return code  -(1) A value returned to a program to indicate the results of an
   operation requested by that program. (2) A code used to influence the
   execution of succeeding instructions.(A)

 reverse video  -(1) A form of highlighting a character, field, or cursor by
   reversing the color of the character, field, or cursor with its background;
   for example, changing a red character on a black background to a black
   character on a red background. (2) In SAA Basic Common User Access
   architecture, a screen emphasis feature that interchanges the foreground and
   background colors of an item.

 REXX Language  -Restructured Extended Executor. A procedural language that
   provides batch language functions along with structured programming
   constructs such as loops; conditional testing and subroutines.

 RGB  -(1) Color coding in which the brightness of the additive primary colors
   of light, red, green, and blue, are specified as three distinct values of
   white light. (2) Pertaining to a color display that accepts signals
   representing red, green, and blue.

 roman  -Relating to a type style with upright characters.

 root segment  -In a hierarchical database, the highest segment in the tree
   structure.

 round-robin scheduling  -A process that allows each thread to run for a
   specified amount of time.

 run time  -(1) Any instant at which the execution of a particular computer
   program takes place. (T)  (2) The amount of time needed for the execution of
   a particular computer program. (T)  (3) The time during which an instruction
   in an instruction register is decoded and performed. Synonym for execution
   time.


ΓòÉΓòÉΓòÉ <hidden> Glossary - S ΓòÉΓòÉΓòÉ

 SAA  -Systems Application Architecture.

 SBCS  -Single-byte character set.

 scheduler  -A computer program designed to perform functions such as
   scheduling, initiation, and termination of jobs.

 screen  -In SAA Basic Common User Access architecture, the physical surface of
   a display device upon which information is shown to a user.

 screen device context  -A logical description of a data destination that is a
   particular window on the screen. See also device context.

 SCREEN$  -Character-device name reserved for the display screen.

 scroll bar  -In SAA Advanced Common User Access architecture, a part of a
   window, associated with a scrollable area, that a user interacts with to see
   information that is not currently allows visible.

 scrollable entry field  -An entry field larger than the visible field.

 scrollable selection field  -A selection field that contains more choices than
   are visible.

 scrolling  -Moving a display image vertically or horizontally in a manner such
   that new data appears at one edge, as existing data disappears at the
   opposite edge.

 secondary window  -A window that contains information that is dependent on
   information in a primary window and is used to supplement the interaction in
   the primary window.

 sector  -On disk or diskette storage, an addressable subdivision of a track
   used to record one block of a program or data.

 segment  -See graphics segment.

 segment attributes  -Attributes that apply to the segment as an entity, as
   opposed to the individual primitives within the segment. For example, the
   visibility or detectability of a segment.

 segment chain  -All segments in a graphics presentation space that are defined
   with the `chained' attribute. Synonym for picture chain.

 segment priority  -The order in which segments are drawn.

 segment store  -An area in a normal graphics presentation space where retained
   graphics segments are stored.

 select  -To mark or choose an item. Note that select means to mark or type in
   a choice on the screen; enter means to send all selected choices to the
   computer for processing.

 select button  -The button on a pointing device, such as a mouse, that is
   pressed to select a menu choice.  Also known as button 1.

 selection cursor  -In SAA Advanced Common User Access architecture, a visual
   indication that a user has selected a choice. It is represented by outlining
   the choice with a dotted box. See also text cursor.

 selection field  -(1) In SAA Advanced Common User Access architecture, a set
   of related choices. See also entry field. (2) In SAA Basic Common User
   Access architecture, an area of a panel that cannot be scrolled and contains
   a fixed number of choices.

 semantics  -The relationships between symbols and their meanings.

 semaphore  -An object used by applications for signalling purposes and for
   controlling access to serially reusable resources.

 separator  -In SAA Advanced Common User Access architecture, a line or color
   boundary that provides a visual distinction between two adjacent areas.

 serial dialog box  -See modal dialog box.

 serialization  -The consecutive ordering of items.

 serialize  -To ensure that one or more events occur in a specified sequence.

 serially reusable resource (SRR)  -A logical resource or object that can be
   accessed by only one task at a time.

 session  -(1) A routing mechanism for user interaction via the console; a
   complete environment that determines how an application runs and how users
   interact with the application. OS/2 can manage more than one session at a
   time, and more than one process can run in a session. Each session has its
   own set of environment variables that determine where OS/2 looks for
   dynamic-link libraries and other important files. (2) (D of C) In the OS/2
   operating system, one instance of a started program or command prompt. Each
   session is separate from all other sessions that might be running on the
   computer. The operating system is responsible for coordinating the resources
   that each session uses, such as computer memory, allocation of processor
   time, and windows on the screen.

 Settings Notebook  -A control window that is used to display the settings for
   an object and to enable the user to change them.

 shadow  -An object that refers to another object. A shadow is not a copy of
   another object, but is another representation of the object.

 shadow box  -The area on the screen that follows mouse movements and shows
   what shape the window will take if the mouse button is released.

 shared data  -Data that is used by two or more programs.

 shared memory  -In the OS/2 operating system, a segment that can be used by
   more than one program.

 shear  -In computer graphics, the forward or backward slant of a graphics
   symbol or string of such symbols relative to a line perpendicular to the
   baseline of the symbol.

 shell  -(1) A software interface between a user and the operating system of a
   computer. Shell programs interpret commands and user interactions on devices
   such as keyboards, pointing devices, and touch-sensitive screens, and
   communicate them to the operating system. (2) Software that allows a kernel
   program to run under different operating-system environments.

 shutdown  -The process of ending operation of a system or a subsystem,
   following a defined procedure.

 sibling processes  -Child processes that have the same parent process.

 sibling windows  -Child windows that have the same parent window.

 simple list  -A list of like values; for example, a list of user names.
   Contrast with mixed list.

 single-byte character set (SBCS)  -A character set in which each character is
   represented by a one-byte code.  Contrast with double-byte character set.

 slider box  -In SAA Advanced Common User Access architecture: a part of the
   scroll bar that shows the position and size of the visible information in a
   window relative to the total amount of information available. Also known as
   thumb mark.

 SOM  -System Object Model.

 source file  -A file that contains source statements for items such as
   high-level language programs and data description specifications.

 source statement  -A statement written in a programming language.

 specific dynamic-link module  -A dynamic-link module created for the exclusive
   use of an application.

 spin button  -In SAA Advanced Common User Access architecture, a type of entry
   field that shows a scrollable ring of choices from which a user can select a
   choice. After the last choice is displayed, the first choice is displayed
   again.  A user can also type a choice from the scrollable ring into the
   entry field without interacting with the spin button.

 spline  -A sequence of one or more BВzier curves.

 spooler  -A program that intercepts the data going to printer devices and
   writes it to disk. The data is printed or plotted when it is complete and
   the required device is available.  The spooler prevents output from
   different sources from being intermixed.

 stack  -A list constructed and maintained so that the next data element to be
   retrieved is the most recently stored. This method is characterized as
   last-in-first-out (LIFO).

 standard window  -A collection of window elements that form a panel. The
   standard window can include one or more of the following window elements:
   sizing borders, system menu icon, title bar, maximize/minimize/restore
   icons, action bar and pull-downs, scroll bars, and client area.

 static control  -The means by which the application presents descriptive
   information (for example, headings and descriptors) to the user. The user
   cannot change this information.

 static storage  -(1) A read/write storage unit in which data is retained in
   the absence of control signals. (A)  Static storage may use dynamic
   addressing or sensing circuits. (2) Storage other than dynamic storage. (A)

 style  -See window style.

 subclass  -A class that is a child of another class. See also Inheritance.

 subdirectory  -In an IBM personal computer, a file referred to in a root
   directory that contains the names of other files stored on the diskette or
   fixed disk.

 swapping  -(1) A process that interchanges the contents of an area of real
   storage with the contents of an area in auxiliary storage. (I)  (A)  (2) In
   a system with virtual storage, a paging technique that writes the active
   pages of a job to auxiliary storage and reads pages of another job from
   auxiliary storage into real storage. (3) The process of temporarily removing
   an active job from main storage, saving it on disk, and processing another
   job in the area of main storage formerly occupied by the first job.

 switch  -(1) In SAA usage, to move the cursor from one point of interest to
   another;  for example, to move from one screen or window to another or from
   a place within a displayed image to another place on the same displayed
   image. (2) In a computer program, a conditional instruction and an indicator
   to be interrogated by that instruction. (3) A device or programming
   technique for making a selection, for example, a toggle, a conditional jump.

 switch list  -See Task List.

 symbolic identifier  -A text string that equates to an integer value in an
   include file, which is used to identify a programming object.

 symbols  -In Information Presentation Facility, a document element used to
   produce characters that cannot be entered from the keyboard.

 synchronous  -Pertaining to two or more processes that depend upon the
   occurrence of specific events such as common timing signals. (T)  See also
   asynchronous.

 System Menu  -In the Presentation Manager, the pull-down in the top left
   corner of a window that allows it to be moved and sized with the keyboard.

 System Object Model (SOM)  -A mechanism for language-neutral, object-oriented
   programming in the OS/2 environment.

 system queue  -The master queue for all pointer device or keyboard events.

 system-defined messages  -Messages that control the operations of applications
   and provides input an other information for applications to process.

 Systems Application Architecture (SAA)  -A set of IBM software interfaces,
   conventions, and protocols that provide a framework for designing and
   developing applications that are consistent across systems.


ΓòÉΓòÉΓòÉ <hidden> Glossary - T ΓòÉΓòÉΓòÉ

 table tags  -In Information Presentation Facility, a document element that
   formats text in an arrangement of rows and columns.

 tag  -(1) One or more characters attached to a set of data that contain
   information about the set, including its identification. (I)  (A)  (2) In
   Generalized Markup Language markup, a name for a type of document or
   document element that is entered in the source document to identify it.

 target object  -An object to which the user is transferring information.

 Task List  -In the Presentation Manager, the list of programs that are active.
   The list can be used to switch to a program and to stop programs.

 terminate-and-stay-resident (TSR)  -Pertaining to an application that modifies
   an operating system interrupt vector to point to its own location (known as
   hooking an interrupt).

 text  -Characters or symbols.

 text cursor  -A symbol displayed in an entry field that indicates where typed
   input will appear.

 text window  -Also known as the VIO window.

 text-windowed application  -The environment in which the operating system
   performs advanced-video input and output operations.

 thread  -A unit of execution within a process. It uses the resources of the
   process.

 thumb mark  -The portion of the scroll bar that describes the range and
   properties of the data that is currently visible in a window. Also known as
   a slider box.

 thunk  -Term used to describe the process of address conversion, stack and
   structure realignment, etc., necessary when passing control between 16-bit
   and 32-bit modules.

 tilde  -A mark used to denote the character that is to be used as a mnemonic
   when selecting text items within a menu.

 time slice  -(1) An interval of time on the processing unit allocated for use
   in performing a task. After the interval has expired, processing-unit time
   is allocated to another task, so a task cannot monopolize processing-unit
   time beyond a fixed limit. (2) In systems with time sharing, a segment of
   time allocated to a terminal job.

 time-critical process  -A process that must be performed within a specified
   time after an event has occurred.

 timer  -A facility provided under the Presentation Manager, whereby
   Presentation Manager will dispatch a message of class WM_TIMER to a
   particular window at specified intervals. This capability may be used by an
   application to perform a specific processing task at predetermined
   intervals, without the necessity for the application to explicitly keep
   track of the passage of time.

 timer tick  -See clock tick.

 title bar  -In SAA Advanced Common User Access architecture, the area at the
   top of each window that contains the window title and system menu icon. When
   appropriate, it also contains the minimize, maximize, and restore icons.
   Contrast with panel title.

 TLB  -Translation lookaside buffer.

 transaction  -An exchange between a workstation and another device that
   accomplishes a particular action or result.

 transform  -(1) The action of modifying a picture by scaling, shearing,
   reflecting, rotating, or translating. (2) The object that performs or
   defines such a modification; also referred to as a transformation.

 Translation lookaside buffer (TLB)  -A hardware-based address caching
   mechanism for paging information.

 Tree  -In the Presentation Manager, the window in the File Manager that shows
   the organization of drives and directories.

 truncate  -(1) To terminate a computational process in accordance with some
   rule (A)  (2) To remove the beginning or ending elements of a string. (3) To
   drop data that cannot be printed or displayed in the line width specified or
   available. (4) To shorten a field or statement to a specified length.

 TSR  -Terminate-and-stay-resident.

 unnamed pipe  -A circular buffer, created in memory, used by related processes
   to communicate with one another. Contrast with named pipe.

 unordered list  -In Information Presentation Facility, a vertical arrangement
   of items in a list, with each item in the list preceded by a special
   character or bullet.

 update region  -A system-provided area of dynamic storage containing one or
   more (not necessarily contiguous) rectangular areas of a window that are
   visually invalid or incorrect, and therefore are in need of repainting.

 user interface  -Hardware, software, or both that allows a user to interact
   with and perform operations on a system, program, or device.

 User Shell  -A component of OS/2 that uses a graphics-based, windowed
   interface to allow the user to manage applications and files installed and
   running under OS/2.

 utility program  -(1) A computer program in general support of computer
   processes; for example, a diagnostic program, a trace program, a sort
   program. (T)  (2) A program designed to perform an everyday task such as
   copying data from one storage device to another. (A)


ΓòÉΓòÉΓòÉ <hidden> Glossary - U ΓòÉΓòÉΓòÉ

There are no glossary terms for this starting letter.


ΓòÉΓòÉΓòÉ <hidden> Glossary - V ΓòÉΓòÉΓòÉ

 value set control  -A visual component that enables a user to select one
   choice from a group of mutually exclusive choices.

 vector font  -A set of symbols, each of which is created as a series of lines
   and curves. Synonymous with outline font. Contrast with image font.

 VGA  -Video graphics array.

 view  -A way of looking at an object's information.

 viewing pipeline  -The series of transformations applied to a graphic object
   to map the object to the device on which it is to be presented.

 viewing window  -A clipping boundary that defines the visible part of model
   space.

 VIO  -Video Input/Output.

 virtual memory (VM)  -Synonymous with virtual storage.

 virtual storage  -(1) The storage space that may be regarded as addressable
   main storage by the user of a computer system in which virtual addresses are
   mapped into real addresses. The size of virtual storage is limited by the
   addressing scheme of the computer system and by the amount of auxiliary
   storage available, not by the actual number of main storage
   locations. (I)  (A)  (2) Addressable space that is apparent to the user as
   the processor storage space, from which the instructions and the data are
   mapped into the processor storage locations. (3) Synonymous with virtual
   memory.

 visible region  -A window's presentation space, clipped to the boundary of the
   window and the boundaries of any overlying window.

 volume  -(1) A file-system driver that uses a block device driver for input
   and output operations to a local or remote device. (I)  (2) A portion of
   data, together with its data carrier, that can be handled conveniently as a
   unit.


ΓòÉΓòÉΓòÉ <hidden> Glossary - W ΓòÉΓòÉΓòÉ

 wildcard character  -Synonymous with global file-name character.

 window  -(1) A portion of a display surface in which display images pertaining
   to a particular application can be presented. Different applications can be
   displayed simultaneously in different windows. (A)  (2) An area of the
   screen with visible boundaries within which information is displayed. A
   window can be smaller than or the same size as the screen. Windows can
   appear to overlap on the screen.

 window class  -The grouping of windows whose processing needs conform to the
   services provided by one window procedure.

 window coordinates  -A set of coordinates by which a window position or size
   is defined; measured in device units, or pels.

 window handle  -Unique identifier of a window, generated by Presentation
   Manager when the window is created, and used by applications to direct
   messages to the window.

 window procedure  -Code that is activated in response to a message. The
   procedure controls the appearance and behavior of its associated windows.

 window rectangle  -The means by which the size and position of a window is
   described in relation to the desktop window.

 window resource  -A read-only data segment stored in the .EXE file of an
   application o the .DLL file of a dynamic link library.

 window style  -The set of properties that influence how events related to a
   particular window will be processed.

 window title  -In SAA Advanced Common User Access architecture, the area in
   the title bar that contains the name of the application and the OS/2
   operating system file name, if applicable.

 Workplace Shell  -The OS/2 object-oriented, graphical user interface.

 workstation  -(1) A display screen together with attachments such as a
   keyboard, a local copy device, or a tablet. (2) (D of C) One or more
   programmable or nonprogrammable devices that allow a user to do work.

 world coordinates  -A device-independent Cartesian coordinate system used by
   the application program for specifying graphical input and output. (I)  (A)

 world-coordinate space  -Coordinate space in which graphics are defined before
   transformations are applied.

 WYSIWYG  -What-You-See-Is-What-You-Get. A capability of a text editor to
   continually display pages exactly as they will be printed.


ΓòÉΓòÉΓòÉ <hidden> Glossary - X ΓòÉΓòÉΓòÉ

There are no glossary terms for this starting letter.


ΓòÉΓòÉΓòÉ <hidden> Glossary - Y ΓòÉΓòÉΓòÉ

There are no glossary terms for this starting letter.


ΓòÉΓòÉΓòÉ <hidden> Glossary - Z ΓòÉΓòÉΓòÉ

 z-order  -The order in which sibling windows are presented. The topmost
   sibling window obscures any portion of the siblings that it overlaps; the
   same effect occurs down through the order of lower sibling windows.

 zooming  -The progressive scaling of an entire display image in order to give
   the visual impression of movement of all or part of a display group toward
   or away from an observer. (I)  (A)

 8.3 file-name format  -A file-naming convention in which file names are
   limited to eight characters before and three characters after a single dot.
   Usually pronounced "eight-dot-three." See also non-8.3 file-name format.


ΓòÉΓòÉΓòÉ <hidden> IBM Trademark ΓòÉΓòÉΓòÉ

Trademark of the IBM Corporation.


ΓòÉΓòÉΓòÉ <hidden> Trademarks ΓòÉΓòÉΓòÉ

Trademark of AT&T, Inc.


ΓòÉΓòÉΓòÉ <hidden> Trademarks ΓòÉΓòÉΓòÉ

Trademark of the Adobe Systems Inc.


ΓòÉΓòÉΓòÉ <hidden> Trademarks ΓòÉΓòÉΓòÉ

Trademark of the Microsoft Corporation.


ΓòÉΓòÉΓòÉ <hidden> Trademarks ΓòÉΓòÉΓòÉ

Trademark of Linotype.


ΓòÉΓòÉΓòÉ <hidden> Trademarks ΓòÉΓòÉΓòÉ

Trademark of Monotype Corporation, Limited.


ΓòÉΓòÉΓòÉ <hidden> Trademarks ΓòÉΓòÉΓòÉ

Trademark of Intel Coporation.