Glossary

A

ABEND

An acronym for ABnormal END, the termination of a task or job before its completion because of an error condition that cannot be resolved by error recovery facilities while the task or job is running.

Access Register

Specialized high speed storage location, 32 bits in size. A z/Architecture processor has 16 ARs, A0-A15. The AR contents are used in ESA/370 (or ESA/390) mode to specify the dataspace to be used by an ESA-exploitative machine instruction.

active block

The currently executing block that invokes the Interactive Debug Facility or any of the blocks in the CALL chain that leads up to this one.

Address Stop

See Storage Alteration Stop.

AdStop

See Storage Alteration Stop.

AdStops window

The IDF window which lists the currently active Storage Alteration Stops (AdStops) and Register Alteration Stops (RegStops). This window is only available on CMS, when IDF's of PER is enabled.

alias

An alternative name for a field.

AR

See Access Register.

argument

Data passed from one program or procedure to another. Contrast with parameter.

ASMIDF

See Interactive Debug Facility.

assemble

To translate a program written in assembly language into a machine-language program.

assembler

A program that translates instructions written in assembly language into machine language.

attention interrupt

An I/O interrupt caused by a terminal or workstation user pressing an attention key, or its equivalent.

attention key

A function key on terminals or workstations that, when pressed, causes an I/O interrupt in the processing unit.

attribute

A characteristic or trait you can specify.

|B

batch

Pertaining to a predefined series of actions performed with little or no interaction between a user and the system. Contrast with interactive.

batch job

A job submitted for batch processing. See batch. Contrast with interactive.

block

In programming languages, a compound statement that coincides with the scope of at least one of the declarations contained within it.

Break window

The IDF window which lists the currently active breakpoints. These include those breakpoints set by the BREAK, DBREAK, and WATCH commands.

breakpoint

A place in a program, normally specified by a command or a condition, where execution can be interrupted and control given to the user or to the Interactive Debug Facility.

C

Command window

The IDF window which contains the command input area, the message display areas, and (optionally) the display of the PF key captions.

compile

To translate a program written in a high level language into a machine-language program.

compile unit

A sequence of statements that make a portion of a program complete enough to compile (or assemble, as appropriate) correctly. Each language has different rules for what comprises a compile unit.

compiler

A program that translates instructions written in a high level programming language into machine language.

condition

Any synchronous event that may need to be brought to the attention of an executing program or the language routines supporting that program. Conditions fall into two major categories: conditions detected by the hardware or operating system, which result in an interrupt; and conditions defined by the programming language and detected by language-specific generated code or language library code. See also exception.

constant

A name used to represent a data item whose value cannot be changed while the program is running. Contrast with variable.

Control Register

Specialized control facility, 32 bits in size. A z/Archtecture processor has 16 GPRs, C0-C15. The CR contents are used to control processor modes and facilities

CR

See Control Register.

Current Registers window

The IDF window which displays the current PSW and registers. By default, the current General Purpose Registers (GPRs) and Floating Point Registers (FPRs) are shown, but the current Access Registers (ARs) or Control Registers (CRs) may be shown instead.

currently qualified

See qualification.

D

data type

A characteristic that determines the kind of value that a field can assume.

data set

The major unit of data storage and retrieval, consisting of a collection of data in one of several prescribed arrangements and described by control information to which the system has access.

DBCS

See double-byte character set.

DCSS

DisContiguous Shared Segment (CMS).

debug

To detect, diagnose, and eliminate errors in programs.

default

A value assumed for an omitted operand in a command. Contrast with initial setting.

disassemble

To translate machine language into assembly language instructions and data statements.

disassembler

A program that translates machine language into assembly language instructions and data statements.

disassembly

The assembly language instructions and data statements which result from using a disassembler to disassemble machine language.

The act of using a disassembler.

Disassembly window

The IDF windows which display the results of an IDF DISASM command. This storage display will normally take the form of disassembled machine instructions. If IDF Language extract data for these storage locations has been loaded with LANGUAGE LOAD, then program source statements will be shown interleaved with the machine instructions. You can control the display of source and disassembly with various IDF commands.

display

A visual presentation of information about a workstation, normally in a specific format. Sometimes called a screen or panel.

display attribute

A characteristic that determines how an item appears on the display. Display attributes can include the color of an item. See also type style.

display line

A viewable line of text in a window, whose exact appearance is determined by factors such as window size.

DLBL

z/VSE only. Disk label information. Further information is available in z/VSE: System Control Statements.

double-byte character set (DBCS)

A set of characters in which each character is represented by two bytes. Languages such as Japanese, which contain more symbols than can be represented by 256 code points, need double-byte character sets. Because each character needs two bytes, the typing, displaying, and printing of DBCS characters needs hardware and programs that support these characters.

dump

The formatted display of storage contents. Typically formatted with a hexadecimal representation of the data on the left, and a character interpretation on the right.

A file or data set containing storage contents, intended for use in offline debug. See also postmortem debug.

Dump window

The IDF windows which display the results of an IDF DUMP command. This storage display will take the form of a dump, with the left side of the display containing the storage contents in hexadecimal, and the right side containing a character interpretation.

dynamic

In programming languages, pertaining to properties that can only be established during the execution of a program; for example, the length of a variable-length data object is dynamic. Contrast with static.

E

entry point

The address or label of the first instruction executed on entering a computer program, routine, or subroutine. A computer program may have a number of different entry points, each perhaps corresponding to a different function or purpose.

exception

An abnormal situation in the execution of a program which typically alters its normal flow. See also condition.

execute

To cause a program, utility, or other machine function to carry out the instructions contained within. See also run.

execution time

See run time.

execution-time environment

See run-time environment.

exit exec

The same as an exit routine.

exit routine

A customization feature which associates an IDF macro or another program with a particular event.

expression

A group of constants or variables separated by operators that yields a single value. An expression can be arithmetic, relational, logical, or a character string.

F

file

A named set of records stored or processed as a unit.

A system object containing records: for example, a VM file, or an z/OS member or partitioned data set. See data set.

Floating Point Register

The CPU has 16 floating-point registers. The floating point registers are identified by the numbers 0-15 and are designated by a four-bit R field in floating point instructions. Each floating-point register is 64 bits long and can contain either a Short (32-bit) or a Long (64-bit) floating-point operand.

FPR

See Floating Point Register.

font

A set of characters or symbols of a given size, shape, and style.

frequency count

In the Interactive Debug Facility, a count of the number of times statements in the currently qualified program unit have been run.

Frequency

A choice located on the Compact Source or Compact Listing window action bar that allows you to monitor the frequency with which program statements are carried out.

full-screen mode

An interface mode for use with a non-programmable terminal which displays a variety of information about the program you are debugging.

G

General Purpose Register

Each register contains 64 bit positions. The general registers are identified by the numbers 0-15.

GPR

See General Purpose Register.

group

A set of records that are associated together as a logical unit.

H

high level language (HLL)

A programming language such as C, PL/I, or COBOL.

HLL

See high level language.

HLASM

Acronym for High Level Assembler.

I

Interactive Debug Facility

The IBM product informally known as IDF, an application development and maintenance facility for debugging assembly language programs.

Interactive Debug Facility macro

A REXX EXEC which contains Interactive Debug Facility commands.

inactive block

A block that is not currently executing, or is not in the CALL chain leading to the active block. See also active block, block.

initial setting

A value in effect when the user's Interactive Debug Facility session begins. Contrast with default.

interactive

Pertaining to a program or system that alternately accepts input and then responds. An interactive system is conversational; that is, a continuous dialog exists between a user and the system. Contrast with batch.

I/O

Input/output.

L

Language Support Module

The IDF subsystem which provides Language Support extensions to the basic machine-level (object-level, disassembly-level) debug capabilities of IDF, originally packaged as a separate module.

LE/370

See IBM Language Environment for z/OS and z/VM.

library routine

A routine maintained in a program library.

line mode

An interface mode for use with a non-programmable terminal which uses a single command line to accept Interactive Debug Facility commands.

link-edit

To create a loadable computer program using a linkage editor.

linkage editor

A program that resolves cross-references between separately compiled object modules and then assigns final addresses to create a single relocatable load module.

listing

A printout that lists the source language statements of a program with all preprocessor statements, includes, and macros expanded.

load module

A program in a form suitable for loading into main storage for execution.

LUname

Defines the VTAM logical unit name of the terminal used by IDF in z/VSE.

LSM

See Language Support Module.

LSM Information window

The IDF windows which contains information generated by IDF Language Support commands.

M

MainFrame Interface (MFI)

This refers to the use of a nonprogrammable terminal such as an IBM 3270.

Maximize

The action used to remove a window entry from the Minimized Windows Viewer, and restore it to its previous position on the display.

MFI

See MainFrame Interface.

Minimize

The action used to remove an IDF window from the display and replaces it with an entry in the Minimized Windows Viewer.

Minimized Windows Viewer

An IDF window which contains entries which represent minimized IDF windows.

module

The "package" which contains the executable code and data for a program. This may be in the form of a file, or an area of storage.

multitasking

A mode of operation that enables the concurrent performance, or interleaved execution, of two or more tasks.

N

name pattern

A set of criteria used to display a list of variable names.

O

Old Registers window

The IDF window which displays the PSW and registers contents from the previous point when IDF had control. By default, the previous General Purpose Registers (GPRs) and Floating Point Registers (FPRs) are shown, but the previous Access Registers (ARs) or Control Registers (CRs) may be shown instead.

Options window

The IDF window which contains current values of the IDF options and settings.

P

panel

In the MFI Interactive Debug Facility, an area of the screen used to display a specific type of information.

parameter

Data received by a program or procedure from another. Contrast with argument.

partitioned data set (PDS)

A data set in direct-access storage that is divided into partitions, called members, each of which can contain a program, part of a program, or data.

path point

A point in the program where control is about to be transferred to another location or a point in the program where control has just been given.

PDS

See partitioned data set.

PER

Program Event Recording

postmortem debug

To detect, diagnose, and eliminate errors in programs after the program has ABENDed. This is typically performed offline, using a dump file or data set.

prefix area

The eight columns to the left of the program source or listing containing line numbers. In the Interactive Debug Facility, statement breakpoints can be set in the prefix area.

primary entry point

See entry point.

Processor Status Word

This register describes the current processor execution state. Various fields contain the current:

addressing mode
execution address
condition-code setting
storage access key
problem or supervisor state indicator
other state indicators

procedure

In a programming language, a block, with or without formal parameters, whose execution is invoked by means of a procedure call.

A set of related control statements. For example, a z/VM exec, or a z/OS CLIST.

profile

A group of customizable settings that govern how the user's session appears and operates.

Profile

A choice that allows you to change some characteristics of the working environment, such as the pace of statement execution in the Interactive Debug Facility.

program

A sequence of instructions suitable for processing by a computer. Processing can include the use of an assembler, a compiler, an interpreter, or a translator to prepare the program for execution, as well as to execute it.

program part

A compile unit associated with an application program. All program parts known to the Interactive Debug Facility are displayed in the MAP window.

program unit

See compile unit.

programmable workstation (PWS)

A workstation that has some degree of processing capability and that allows you to change its functions (for example, a small computer such as an IBM Personal System/2^* (PS/2^*) as a terminal device along with appropriate 3270 emulation software).

PSW

See Processor Status Word.

PWS

See programmable workstation.

Q

qualification

A method used to specify to what procedure or load module a particular variable name, function name, label, or statement id belongs. The SET QUALIFY command changes the current implicit qualification.

R

record

A group of related data, words, or fields treated as a unit, such as one name, address, and telephone number.

record format

The definition of how data is structured in the records contained in a file. The definition includes record name, field names, and field descriptions, such as length and data type. The record formats used in a file are contained in the file description.

reference

In programming languages, a language construct designating a declared language object.

A subset of an expression that resolves to an area of storage; that is, a possible target of an assignment statement. It can be any of the following: a variable, an array or array element, or a structure or structure element. Any of the above can be pointer-qualified where applicable.

Register

Specialized high speed storage location or control facility. See General Purpose Register, Floating Point Register, Access Register, and Control Register.

Register Alteration Stop

This is a special breakpoint available when IDF on CMS has exploitation of the virtual machine Program Event Recorder (PER) mode enabled. IDF will receive control when any of the specified registers is altered.

Register Stop

See Register Alteration Stop.

RegStop

See Register Alteration Stop.

run

To cause a program, utility, or other machine function to execute.

An action that causes a program to begin execution and continue until a run-time exception occurs. If a run-time exception occurs, you can use debug windows to interact with the Interactive Debug Facility.

run time

Any instant at which a program is being executed.

run-time environment

A set of resources that are used to support the execution of a program.

run unit

A group of one or more object programs that are run together.

S

SBCS

See single-byte character set.

semantic error

An error in the implementation of a program's specifications. The semantics of a program refer to the meaning of a program. Unlike syntax errors, semantic errors (since they are deviations from a program's specifications) can be detected only at run time.

sequence number

A number that identifies the records within a z/VM file, or a z/OS member or partitioned data set.

session

The events that take place between the time you start an application and the time you exit the application.

shortcut keys

A key or combination of keys that starts an application-defined function. The IDF user interface term for accelerator keys or hot keys.

single-byte character set (SBCS)

A character set in which each character is represented by a one-byte code.

Skipped Subroutines window

The IDF window which lists the currently active "Skipped Subroutine" breakpoints. These are set by the SKIPSTEP command.

source

The statements in a file that make up a program.

In Interactive Debug Facility, the representation of a program's source statements displayed in the Disassembly window.

static

In programming languages, pertaining to properties that can be established before execution of a program; for example, the length of a fixed length variable is static. Contrast with dynamic.

status area

An area appended to a window that shows the keyboard shift state for DBCS on a DBCS-enabled workstation.

step

One statement in a computer routine.

To cause a computer to execute one or more statements.

storage

A unit into which recorded text can be entered, in which it can be retained, and from which it can be retrieved.

The action of placing data into a storage device.

A storage device.

Storage Alteration Stop

This is a special breakpoint available when IDF on CMS has exploitation of the virtual machine Program Event Recorder (PER) mode enabled. IDF will receive control when storage within the specified address ranges is altered.

subroutine

A sequenced set of instructions or statements that can be used in one or more computer programs at one or more points in a computer program.

suffix area

A variable-sized column to the right of the program source or listing statements, containing frequency counts for the first statement or verb on each line. In the Interactive Debug Facility, the MFI optionally displays the suffix area in the Disassembly window. See also prefix area.

synchronous

Pertaining to two or more processes that depend on the occurrence of specific events. Contrast with batch, interactive.

syntactic analysis

An analysis of a program done by a compiler to determine the structure of the program and the construction of its source statements to determine whether it is valid for a given programming language. See also syntax error.

syntax

The rules governing the structure of a programming language and the construction of a statement in a programming language.

syntax error

Any deviation from the grammar (rules) of a given programming language appearing when a compiler performs a syntactic analysis of a source program. See also syntactic analysis.

T

Target Status window

The IDF window which lists information about the program modules which are currently defined to IDF.

token

A character string in a specific format that has some defined significance in a programming language.

triglyph

A group of three characters which, taken together, are equivalent to a single special character.

type style

A form of highlighting of characters and symbols within a font set. For example, bold, italic, strikeout, or underscore. See also display attribute.

U

utility

A computer program in general support of computer processes; for example, a diagnostic program, a trace program, or a sort program.

V

variable

A name used to represent a data item whose value can be changed while the program is running. Contrast with constant.

W

window

A division of the display screen in which one of several IDF commands can concurrently display information.

windowing

Dividing a display screen into distinct areas in which different display images can be viewed at the same time.

workstation

One or more programmable or nonprogrammable devices, normally connected to a host or a network, at which you can run applications. See also programmable workstation.