Glossary

Absolute Address. An address that either should not be incremented or has already been incremented by a relocation factor.

Absolute Program. A program which, although stored in disk system format, has been written in such a way that it can be executed from only one core location.

Assembler Core. Load A core load that was built from a mainline written in Assembler language.

CALL Subprogram. A subprogram that must be referenced with a CALL statement. The type codes for subroutines in this category are 4 and 6.

CALL TV. The transfer vector through which CALL subroutines are entered during execution. See the section on the Core Load Builder for a description of this transfer vector.

Card Core Image Format (abbr. CDC). The format in which a program stored in disk core image format is dumped to cards.

Card Data Format (abbr. CDD). The format in which a data file is dumped to cards.

Card System Format (abbr. CDS). The format in which absolute and relocatable programs are punched into cards. In this format, columns 73-80 are used only to contain the card ID and sequence number.

Checksum. The two's complement of the logical sum of the record count (the position of the record within the program) and the data word(s). The logical sum is obtained by summing the data word(s) and the record number arithmetically, with the addition of one each time a carry occurs out of the high-order position of the Accumulator. The first record is record 1, not record 0.

This term (record number) should not be confused with the sequence number that appears in columns 73-80 in card formats. CIB. (See Core Image Buffer.)

Cold Start Card. The card that contains the coding necessary for initial program loading (IPL), that is, fetching the Cord Start Program.

Cold Start Program. The disk-resident program that initializes the Monitor system by reading the Resident Monitor into core from the disk.

Comment. The text contained on a Monitor control record with an asterisk in column 4, an Assembler language source record with an asterisk in column 21, or a FORTRAN source record with a C in column 1.

Control Record. One of the records (card or paper tape) that direct the activities of the Monitor system. For example, the DUP Monitor control record directs the Monitor to initialize DUP, the DUMPLET DUP control record directs DUP to initialize the DUMPLET program; the EXTENDED PRECISION FORTRAN control record directs the Compiler to allot three words instead of two for the storage of variables.

Core Communications Area (abbr. COMMA). The part of core which is reserved for work areas and parameters that are required by the Monitor programs. In general a parameter is found in COMMA if it is required by two or more Monitor programs and is required to load a program stored in disk core image format. Otherwise the parameter is found in DCOM. COMMA is initialized by the Supervisor during the processing of a JOB record. Core Image Buffer (abbr. CIB) The buffer on which most of the first 4K of core are saved while a core load is being built. It is also used to save any part of COMMON defined below location 4096 during a link-to-link transfer of control. See the section on the Core Load Builder for a description of the CIB and its use.

Core Image Header Record. A part of a core image program including such parameters as the word count of the core load, the ITV, and the setting for index register 3.

Core Image Program. A mainline that has been converted, along with all of its required subroutines, to disk core image format. Included in the core image program are any LOCALs and/or SOCALs that are required. This term should not be confused with "core load", which refers to only that part of a core image program that is read into core just prior to execution.

Core Load. A mainline, its required subroutines, and its interrupt, CALL, and LIBF transfer vectors. This term should not be confused with "core image program".

CSF Block. A group of not more than 51 data words of a program in card system format. In this format, the first six data words of every CSF block are indicator words. These six words are always present, even though all six are not needed. A CSF block is equivalent to words 4-54 of the CSF module (Data card) of which it is a part.

CSF Module. A group of words consisting of a data header and CSF blocks for a program in card system format. A CSF module is equivalent to a Data card in card system format. A new CSF module is created for every data break. A data break occurs (1) whenever there is an ORG, BSS, BES, or DSA statement, (2) whenever a new Data card is required to store the words comprising a program, and (3) at the end of the program.

Data File. An area in either the User Area or the Fixed Area in which data is stored. "Data file" may also refer to the data itself.

Data Header. The first pair of words in a module for a program in disk system format. The first word contains the loading address of the module; the second the total number of words contained in the module. The data header for the last module contains the effective program length, followed by a word count of zero.

DEFINE FILE Table. The table which appears at the beginning of every mainline that refers to defined files. There is one 7-word entry for each file that has been defined.

Disk Block. One sixteenth of a disk sector, that is, 20 disk words. The disk block is the smallest distinguishable increment for programs stored in disk system format. Thus, the Monitor system permits packing of disk system format programs at smaller intervals than the hardware would otherwise allow.

Disk Communications Area (abbr. DCOM). The disk sector that contains the work areas and parameters for the Monitor programs.

Disk Core Image Format (abbr. DCI). The format in which core image programs are stored on the disk prior to execution.

Disk Data Format (abbr. DDF). The format in which data file is stored in either the User Area or the Fixed Area.

Disk System Format (abbr. DSF). The format in which mainlines and subprograms are stored on the disk as separate entities. It is not possible to execute a program in disk system format; it must first be converted to disk core image format as a result of either an XEQ Monitor control record or a STORE CI DUP control record.

Disk System Format Program. A program that is stored in disk system format. It is sometimes called a DSF program.

DSF Block. A group of not more than nine data words of a program in disk system format. In this format, the first data word of every DSF block is an indicator word. Normally every DSF block in a DSF module consists of nine data words, including an indicator word; but if the DSF module contains a number of data words that is not a multiple of nine, then the next-to-last DSF block contains less than nine data words.

DSF Module. A group of words consisting of a data header and DSF blocks for a program in disk system format. A new DSF module is created for every data break. A data break occurs (1) whenever there is an ORG, BSS, BES, or DSA statement, (2) whenever a new sector is required to store the words comprising a program, and (3) at the end of the program.

Effective Program Length. The terminal address appearing in a relocatable program. For example, in Assembler language programs, this address is the last value taken on by the Location Assignment Counter and appears as the address assigned to the END statement.

Entry Point. Either (1) the symbolic address (name) of a place at which a program is entered, (2) the absolute core address at which a program is to be entered, or (3) the address, relative to the address of the first word of the subprogram, at which it is to be entered.

Execution. The execution of the program specified on an XEQ Monitor control record and any subsequent links executed via CALL LINK statements. The execution is complete when a CALL EXIT is executed.

Fetching. The process of reading something into core storage, usually from disk.

Fixed Area (abbr. FX). The area on disk in which core image programs and data files are stored if it is desired that they always occupy the same sectors. No programs in disk system format may be stored in this area. No packing ever occurs in the Fixed Area.

FORTRAN Core Load. A core load that was built from a mainline written in the FORTRAN language.

Function. A subprogram that evaluates a mathematical relationship between a number of variables. In FORTRAN, a FUNCTION is a subprogram that is restricted to a single value for the result. This type of subprogram is called by direct reference.

IBM Area. That part of disk storage that is occupied by DCOM, the CIB, and the Monitor programs. This area is also known as the System Area.

ILS Branch Table (abbr. IBT). A table consisting of the addresses of the interrupt entry points for each ISS used for an interrupt level. An IBT is required by the ILS for an interrupt level with which more than one device is associated.

In-core Subprogram. A subprogram that remains in core storage during the entire execution of the core load, of which it is a part. ILSs are always in-core subprograms, whereas LOCALs and SOCALs never are.

Indicator Word. The first word of a DSF block indicating which of the following data words should be incremented (relocated) when relocating a program in disk system format. This word also indicates which words are LIBF, CALL, and DSA names. Programs in disk system format all contain indicator words. Each pair of bits in the indicator word is associated with one of the following data words -- the first pair with the first data word following the indicator word, etc.

Initial Program Load. The action that occurs when the PROGRAM LOAD key is pressed. One record is read into core, starting at location zero, from the input hardware device that is physically wired to perform this function. The record read, usually a loader, then instructs the system as to the next action to be performed, e.g., load more records.

Interrupt Level Subroutine (abbr. ILS). A subroutine that analyzes all interrupts on a given level; that is, it determines which device on a given level caused the interrupt and branches to a servicing subroutine (ISS) for the processing of that interrupt.

Interrupt Service Subroutine (abbr. SS). A subroutine that 1) manipulates a given I/O device and 2) services all interrupts for that devicer after they have been detected by an ILS.

Interrupt Transfer Vector (abbr. ITV). The contents of words 8-13, which are the second words of the automatic BSI instructions which occur with each interrupt. In other words, if an interrupt occurs on level zero and if core location eight contains 500, an automatic BSI to core location 500 occurs. Similarly, interrupts on levels 1-5 cause BSIs to the contents of core locations 9-13, respectively.

IOAR Header. The word(s) required by an I/O device subroutine (ISS). They must be the first or the first and second words of the I/O buffer.

ISS Counter. A counter in COMMA (word $IOCT) that is incremented by 1 upon the initiation of every I/O operation and decremented by 1 upon receipt of an I/O operation complete interrupt.

Job. A group of tasks (subjobs) that are to be performed by the Monitor system and which are interdependent; that is, the successful execution of any given subjob (following the first) depends upon the successful execution of at least one of those that precede it.

LET/FLET (the Location Equivalence Table for the User Area/ the Location Equivalence Table for the Fixed Area). The disk-resident table through which the disk addresses of programs and data files stored in the User/Fixed Area may be found. On a system cartridge, LET occupies the cylinder preceding the User Area. If a Fixed Area has been defined, FLET occupies the cylinder preceding it; otherwise, there is no FLET.

LIBF Subroutine. A subprogram that must be referenced with an LIBF statement. The type codes for subroutines in this category are 3 and 5.

LIBF TV. The transfer vector through which LIBF subprograms are entered at execution time. See the section on the Core Load Builder for a description of this transfer vector.

Link. A link is a core image program that is read into core for execution as a result of the execution of a CALL LINK statement.

Loading Address. The address at which a mainline, subprogram, core load, or DSF module is to begin. For mainlines and DSF modules, the loading address is either absolute or relative. For subprograms, it is always relative, whereas, for core loads, it is always absolute.

Load-On-Call (abbr. LOCAL) Subroutine. A subprogram in a core image program that is not an in-core subprogram.. It is read from the disk into a special overlay area in core only when it is called during execution time. LOCALs, which are specified for any given execution by the user, are a means of gaining core storage at the expense of execution time. The Core Load Builder constructs the LOCALs and all linkages to and from them.

Load-Although-Not-Called (abbr. NOCAL Subprogram). A subprogram that is to be included in a core image program although it is never referenced in that core image program by an LIBF or CALL statement. Debugging aids such as a trace or a dump fall into this category.

Location Assignment Counter. A counter maintained in the Assembler for assigning addresses to the instructions it assembles. A similar counter is maintained in the Core Load Builder for loading purposes.

Low COMMON. Words 896 - 1215 if DISKZ is in core, words 1216 - 1535 if DISK1 is in core, or words 1536 - 1855 is DISKN is in core. This area exists even if there is no COMMON.

Mainline. The program about which a core image program is built. The mainline is normally the program in control. It calls subprograms to perform various functions.

Master Cartridge. The cartridge residing on logical drive zero. The master cartridge must be a system cartridge.

Modified EBCDIC Code. A six-bit code used internally by the Monitor programs. In converting from EBCDIC to Modified EBCDIC, the leftmost two-bits are dropped. (See Name Code.)

Monitor. A synonym for the entire 1130 Disk Monitor System, Version 2, which is also known as the Monitor system or the Disk Monitor.

Monitor Program. One of the following parts of the Monitor system: Supervisor (SUP), Core Image Loader (CIL), Core Load Builder (CLB), Disk Utility Program (DUP), Assembler (ASM), or FORTRAN Compiler (FOR).

Name Code. The format in which the names of subprograms, entry points, labels, etc. , are stored for use in the Monitor programs. The name consists of five characters, terminal blanks being added if necessary to make five characters. Each character is in Modified EBCDIC code, and the entire 30-bit representation is right-justified in two 16-bit words. The leftmost two bits are used for various purposes by the Monitor.

Naturally Relocatable Program. A program that may be executed from any core storage location without first being relocated. The only absolute addresses in such a program refer to parts of the Resident Monitor, which, of course, are fixed.

Non-system Cartridge. A cartridge that does not contain the Monitor programs, although it does contain DCOM, LET, etc. A non-system cartridge may be used only as a satellite cartridge.

NOP. An acronym used to denote the instruction, No operation. Object Program The output from either the Assembler, or the FORTRAN Compiler.

Packing. The process of storing programs in the User Area to the nearest disk block, thus reducing the average wasted disk space from 160 disk words/program to 10 disk words/program.

Padding. Areas in the User/Fixed Area required to permit core image programs and data files to start on a sector boundary. The length of the padding, which is reflected in LET/FLET with a dummy entry, is from 1 to 15 disk blocks.

Principal I/O Device. The device used for stacked job input to the Monitor system. The 2501/1442, 1442/1442, or 1134/1055 may be assigned as the principal I/o device. The Keyboard may be assigned temporarily as the principal input device (see // TYP under Monitor Control Records) The System Loader considers the fastest device defined on the REQ records to be the principal I/o device.

Principal Print Device. The device used by the Monitor system for printing system messages. Either the 1403, 1132, or Console Printer may be assigned as the principal print device. The System Loader considers the fastest print device defined on the REQ records to be the principal print device.

Program. The highest level in the hierarchy describing various types of code. Subprograms and mainlines are subsets of this set.

Program Header Record. The part of a program stored in disk system format that precedes the first DSF modale. Its contents vary with the type of program with which it is associated. It contains the information necessary to identify the program, to describe its properties, and to convert it from disk system format to disk core image format.

Quintuples. Five-word tables in DCOM that contain cartridge-related parameters. There is one table for each parameter and an entry in the table for each cartridge on the system. These tables are updated by SYSUP during JOB processing or by a user callable subprogram SYSUP if cartridges are changed during a job.

Relocatable Program. A program that can be executed from any core location. Such a program is stored on the disk in disk system format. It is relocated by the Core Load Builder.

Relocation. The process of adding a relocation factor to address constants and to those long instructions whose second words are not (1) invariant quantities, (2) absolute core addresses, or (3) symbols defined as absolute core addresses. The relocation factor for any program is the absolute core address at which the first word of that program is found.

Relocation Indicator. The second bit in a pair of bits in an indicator word. If the data word with which this bit is associated is not an LIBF, CALL, or DSA name, then it indicates whether or not to relocate the data word. If the relocation indicator is set to 1, the word is to be relocated. Pairs of relocation indicators indicate LIBF, CALL, or DSA names. The combinations are 1000, 1100, and 1101, respectively.

Remark. An explanation of the use or function of a statement or statements. A remark is a part of a statement, whereas a comment is a separate statement.

Resident Image. The mirror-image of the Resident Monitor minus the disk I/o subroutine. It resides on disk and is read into core by the Cold Start Program.

Resident Monitor. The area required in core by the Monitor system for its operation. This area is generally unavailable to the user for his own use. The Resident Monitor consists of COMMA, the Skeleton Supervisor, and one of the disk I/o subroutines, nominally DISKZ.

Satellite Cartridge. A cartridge residing on a drive other than logical drive zero. A satellite cartridge can be either a system or a non-system cartridge.

Skeleton Supervisor. The part of the Supervisor that is always in core and that is, essentially, the logic necessary to process CALL DUMP, CALL EXIT, and CALL LINK statements. Certain traps are also considered to be part of the Skeleton Supervisor.

Subjob. A Monitor operation to be performed during a job. Each subjob is initiated by a Monitor control record such as ASM or XEQ. It may also be initiated by a CALL LINK.

Subprogram. A synonym used mainly in FORTRAN for both FUNCTIONs and SUBROUTINEs. This term is equivalent to subroutine when subroutine is used in its broadest sense.

Subroutine. A subset of the set "program'. In FORTRAN, a SUBROUTINE is a type of subprogram that is not restricted to a single value for the result and that is called with a CALL statement.

Supervisor Control Record Area (abbr. SCRA). The cylinder in which the Supervisor control records are written. The first two sectors are reserved for LOCAL control records, the next two for NOCAL control records and the next two for FILES control records. See the Supervisor section for the formats of these records.

System Cartridge. A cartridge that contains the Monitor programs. A system cartridge may be used as either a master or a satellite cartridge.

System Overlay to be Loaded-On-Call (abbr. SOCAL). One of two or three overlays automatically prepared by the Core Load Builder under certain conditions when a core load is too large to fit into core storage. See the section on the Core Load Builder for an explanation.

System Working Storage. The Working Storage area to be used during a job by the Monitor programs. The cartridge to be used for System Working Storage is defined on the JOB record. System Working Storage need not be on the system cartridge.

User Area (abbr. UA). The area on the disk in which all programs in disk system format are found. Core image programs and data files may also be stored in this area. All IBM-supplied programs are found here. This area occupies as many sectors as are required to store the programs and files residing there.

User Programs. Mainlines, subprograms, or core loads that have been written by the user and stored in the User/Fixed Area.

Working Storage (abbr. WS). The area on disk immediately following the last sector occupied by the User Area. This is the only one of the three major divisions of disk storage (IBM Area, User/Fixed Area, Working Storage) that does not begin at a cylinder boundary.

GLOSSARY