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This glossary defines technical terms and abbreviations used in z/OS Language Environment® documentation.
If you do not find the term you are looking for, refer to the index
of the appropriate Language
Environment publication or view IBM® Glossary
of Computing Terms, located at:
IBM Glossary of Computing Terms This
glossary includes terms and definitions from: Portable Operating
System Interface (POSIX) Part 1: System Application Program Interface
(API) [C Language], ISO/EIC 9945-1: 1990, IEEE Std 1003.1-1990,
copyright 1992 by The Institute of Electrical and Electronics Engineers,
Inc., 345 East 47th Street, New York, NY 10017. These terms are identified
by [POSIX.1]. - abend
- Abnormal end of application.
- absolute value
- The magnitude of a real number regardless of its algebraic sign.
- active routine
- The currently executing routine.
- actual argument
- The Fortran term for the data passed to a called routine at the
point of call. See also dummy argument.
- additional floating point registers (AFP)
- For IEEE support, 12 additional floating point registers, for
a total of 16 floating-point registers.
- additional heap
- A Language Environment heap
created and controlled by a call to CEECRHP. See also below heap,
anywhere heap, and initial heap.
- addressing mode
- An attribute that refers to the address length that a routine
is prepared to handle upon entry. Addresses may be 24 or 31 bits long.
- address space
- Domain of addresses that are accessible by an application.
- AFP
- See additional floating-point registers (AFP).
- aggregate
- A structured collection of data items that form a single data
type. Contrast with scalar.
- AIB
- Application interface block.
- ALLOCATE command
- In MVS™, the TSO command that
serves as the connection between a file's logical name (the ddname)
and the file's physical name (the data set name).
- American National Standard Code for Information Interchange (ASCII)
- The code developed by the American National Standards Institute
(ANSI) for information interchange among data processing systems,
data communications systems, and associated equipment. The ASCII character
set consists of 7-bit control characters and symbolic characters.
- AMODE
- Provided by the linkage editor, the attribute of a load module
that indicates the addressing mode in which the load module should
be entered.
- AMODE 31
- Addressing mode 31.
- AMODE 64
- Addressing mode 64.
- anywhere heap
- The Language Environment heap
controlled by the ANYHEAP runtime option. It contains library data,
such as Language Environment control
blocks and data structures not normally accessible from user code.
The anywhere heap may reside above 16M. See also below heap, additional
heap, initial heap.
- APAR
- Authorized program analysis report.
- application
- A collection of one or more routines cooperating to achieve particular
objectives.
- application interface block (AIB)
- IMS™ interface between an
application and an IMS database.
- application program
- A collection of software components used to perform specific types
of work on a computer, such as a program that does inventory control
or payroll.
- argument
- 1) An expression used at the point of a call to specify a data
item or aggregate to be passed to the called routine. 2) The data
passed to a called routine at the point of call or the data received
by a called routine. See also actual argument and dummy
argument.
- array
- An aggregate that consists of data objects, each of which may
be uniquely referenced by subscripting.
- array element
- A data item in an array.
- ASCII
- American National Standard Code for Information Interchange.
- Asian date format
- In this book, Asian date format refers to the era picture strings
associated with the Japanese or other era. Era picture strings begin
with a less than character (<) and end with a greater than character
(>). The characters inside are either capital Js or Cs.
- assembler
- Translates symbolic assembler language into binary machine language.
The High Level Assembler is an IBM licensed
program.
- assembler user exit
- A routine to tailor the characteristics of an enclave prior to
its establishment. The name of the routine is CEEBXITA.
- async safe
- An application is able to mask off asynchronous signals when it
is working with critical data or structures. The application can request
to process the asynchronous signals when it has finished updated the
critical data or structure.
- atexit list
- A list of actions specified in the C atexit() function
that occur at normal program termination.
- authorized program analysis report (APAR)
- A request for correction of a problem caused by a defect in a
current unaltered release of a program.
- automatic call
- The process used by the linkage editor to resolve external symbols
left undefined after all the primary input has been processed. See
also automatic call library.
- automatic call library
- Contains load modules or object modules that are to be used as
secondary input to the linkage editor to resolve external symbols
left undefined after all the primary input has been processed.
The
automatic call library may be: - Libraries containing object modules, with or without linkage editor
control statements
- Libraries containing load modules
- The library containing Language Environment runtime
routines (SCEELKED) (SCEELKED and SAFHFORT)
- automatic conversion
- For Enhanced ASCII functionality, the automatic conversion of
text data from EBCDIC to ASCII, or from ASCII to EBCDIC, as part of
using internationalized applications developed on (or for) ASCII platforms
and ported to z/OS® platforms.
See also file tag and coded character set ID (CCSID).
- automatic data
- Data for a routine that is automatically allocated when the routine
is called and automatically freed when the routine returns. Automatic
data does not persist from one call of the routine to the next.
- automatic library call
- Automatic call. See also automatic call library.
- automatic storage
- Storage that is allocated on entry to a routine or block and is
freed on the subsequent return. Sometimes referred to as stack
storage or dynamic storage.
- AWI
- Application writer interface.
- background process
- A process that is a member of a background process group. [POSIX.1]
- background process group
- Any process group, other than a foreground process group, that
is a member of a session that has established a connection with a
controlling terminal. [POSIX.1]
- base
- The core product, upon which features may be separately ordered
and installed.
- batch
- Pertaining to activity involving little or no user action. Contrast
with interactive.
- below heap
- The Language Environment heap
controlled by the BELOWHEAP runtime option, which contains library
data, such as Language Environment control
block and data structures not normally accessible from user code.
Below heap always resides below 16M. See also anywhere heap, initial
heap, additional heap.
- BFP
- See binary floating point (BFP).
- binary floating point
- For IEEE, binary floating point registers.
- binder
- The DFSMS component that processes the output of the language
translators and compilers into an executable program (load module
or program object). It replaces the linkage editor and batch loader
in the MVS/ESA operating
system.
- breakpoint
- A place in a program, usually specified by a command or a condition,
where execution may be interrupted and control given to the workstation
user or to a specified debug tool program.
- buffer
- An area of storage into which data is read or from which it is
written. Typically, buffers are used only for temporary storage.
- by content
- See pass by content.
- by reference
- See pass by reference.
- by value
- See pass by value.
- byte
- The basic unit of storage addressability. It has a length of 8
bits.
- C language
- A high-level language used to develop software applications in
compact, efficient code that can be run on different types of computers
with minimal change.
- C++ language
- An object-oriented high-level language that evolved from the C language. C++ exploits
the benefits of object-oriented technology such as code modularity,
portability, and reuse.
- C-CAA
- C/370-specific common anchor area in the runtime environment.
- CAA
- Common anchor area.
- call chain
- A trace of all active routines and subroutines that can be constructed
by the user from information included in a system dump, such as the
locations of save areas and the names of routines.
- callable service stub
- A short routine that is link-edited with an application and that
is used to transfer control from the application to a callable service.
- callable services
- A set of services that can be invoked by a Language Environment-conforming
high-level language using the conventional Language Environment-defined
call interface, and usable by all programs sharing the Language Environment conventions.
Use of these services helps to decrease an application’s dependence
on the specific form and content of the services delivered by any
single operating system.
- called routine
- A routine or program that is invoked by another.
- callee
- A routine or program that is invoked by another.
- caller
- A routine or program that invokes another routine.
- calling routine
- A routine or program that invokes another routine.
- CASE
- Computer-aided software engineering.
- cast
- In C, an expression that converts the type of the operand to a
specified data type (the operator).
- cataloged procedure
- A set of job control language (JCL) statements placed in a library
and retrievable by name.
- CBIPO
- Custom-Built Installation Process Offering.
- CBPDO
- Custom-Built Product Delivery Offering.
- CCSID
- See coded character set ID (CCSID).
- CEEDUMP
- A dump of the runtime environment for Language Environment and the
member language libraries. Sections of the dump are selectively included,
depending on options specified on the dump invocation. This is not
a dump of the full address space, but a dump of storage and control
blocks that Language
Environment and its members control.
- century window
- The 100-year interval in which Language Environment assumes
all 2-digit years lie. The Language Environment default
century window begins 80 years before the system date.
- chained list
- Synonym for linked list.
- character
- A letter, digit, or other symbol. A letter, digit, or other symbol
that is used as part of the organization, control, or representation
of data. A character is often in the form of a spatial arrangement
of adjacent or connected strokes.
- child enclave
- The nested enclave created as a result of certain commands
being issued from a parent enclave.
- CIB
- Condition information block.
- CICS®
- Customer Information Control System.
- CICS destination control
table (DCT)
- A table that contains an entry for each extrapartition, intrapartition,
and indirect destination. Extrapartition entries address data sets
external to the CICS region.
Intrapartition destination entries contain the information required
to locate the queue in the intrapartition data set. Indirect destination
entries contain the information required to locate the queue in the
intrapartition data set.
- CICS OTE
- CICS Open Transaction Environment.
- CICS run unit
- Consists of a statically and/or dynamically bound set of one or
more load modules which can be loaded by a CICS loader. A CICS run
unit is equivalent to a Language Environment enclave.
- CICS translator
- A routine that accepts as input an application containing EXEC CICS commands and produces as output
an equivalent application in which each CICS command
has been translated into the language of the source.
- CLIST
- TSO command list.
- CLLE
- COBOL load list entry.
- CMS
- Conversational monitor system.
- CMS extended parameter list
- A type of parameter list available in the CMS environment consisting
of a string composed exactly as the user typed it at the terminal.
There is no tokenization performed on the string.
- CMS tokenized parameter list
- A type of parameter list available in the CMS environment consisting
of 8-byte tokens, folded to uppercase, terminating with a double word
of X'FF'. Not supported under Language Environment.
- COBCOM
- Control block containing information about a COBOL partition.
- COBOL
- COmmon Business-Oriented Language. A high-level language, based
on English, that is primarily used for business applications.
- COBOL load list entry (CLLE)
- Entry in the load list containing the name of the program and
the load address.
- COBOL run unit
- A COBOL-specific term that defines the scope of language semantics.
Equivalent to a Language Environment enclave.
- COBPACK
- A collection of individual modules that are packaged into a single
load module in order to reduce the time that would otherwise be needed
to load the individual load modules.
- COBVEC
- A COBOL vector table containing the address of the COBOL library
routines.
- coded character set ID (CCSID)
- For Enhanced ASCII functionality, a 16-bit value is a number that
represents a character set used by file tagging. It identifies the
currrent character set of text strings within a program. This is stored
in the file tag of new files or used for the automatic conversion
of old files when automatic conversion is in effect. See also automatic
conversion and file tag.
- command processor parameter list (CPPL)
- The format of a TSO parameter list. When a TSO terminal monitor
application attaches a command processor, register 1 contains a pointer
to the CPPL, containing addresses required by the command processor.
- COMMAREA
- A communication area made available to applications running under CICS.
- common anchor area (CAA)
- Dynamically acquired storage that represents a Language Environment thread.
Thread-related storage/resources are anchored off of the CAA. This
area acts as a central communications area for the program, holding
addresses of various storage and error-handling routines, and control
blocks. The CAA is anchored by an address in register 12.
- common block
- A storage area that may be referenced by one or more compilation
units. It is declared in a Fortran program with the COMMON statement.
See also external data.
- compilation unit
- An independently compilable sequence of HLL statements. Each HLL
product has different rules for what makes up a compilation unit.
Synonymous with program unit.
- compile-time options
- Keywords that can be specified to control certain aspects of compilation.
Compiler options can control the nature of the load module generated
by the compiler, the types of printed output to be produced, the efficient
use of the compiler, the destination of error messages, and other
things.
- compiler options
- Keywords that can be specified to control certain aspects of compilation.
Compiler options can control the nature of the load module generated
by the compiler, the types of printed output to be produced, the efficient
use of the compiler, and the destination of error messages. See also compiler-time
options.
- component
- A set of modules that performs a major function within a system.
- computer-aided software engineering (CASE)
- A software engineering discipline for automating the application
development process and thereby improving the quality of application
and the productivity of application developers.
- condition
- An exception that has been enabled, or recognized, by Language Environment and
thus is eligible to activate user and language condition handlers.
Conditions can be detected by the hardware/operating system and result
in an interrupt. They can also be detected by language-specific generated
code or language library code.
- condition code
- A code that reflects the result of a previous input/output, arithmetic,
or logical operation.
- condition handler
- A user-written routine or language-specific routine (such as a PL/I ON-unit
or C signal() function
call) invoked by the Language Environment condition
manager to respond to conditions.
- condition handling
- In Language Environment,
the diagnosis, reporting, and/or tolerating of errors that occur while
a routine is running.
- condition information block (CIB)
- The platform-specific data block used by the Language Environment condition
manager as a repository for data about conditions raised in the Language Environment runtime
environment.
- condition manager
- Manages conditions in the common execution environment by invoking
various user-written and language-specific condition handlers.
- condition step
- The step of the Language Environment condition
handling model that follows the enablement step. In the condition
step, user-written condition handlers, C signal handlers, and PL/I ON-units
are first given a chance to handle a condition. See also enablement
step and termination imminent step.
- condition token
- In Language Environment,
a data type consisting of 96 bits (12 bytes). The condition token
contains structured fields that indicate various aspects of a condition
including the severity, the associated message number, and information
that is specific to a given instance of the condition.
- condition variable
- A data object that is used for waiting for long durations of time.
An application can wait for the variable to become true before continuing
processing. [POSIX.1]
- conflicting name
- One of 20 names that exist in both the Fortran and the C/C++ libraries.
See also conflicting reference.
- conflicting reference
- An external reference from a Fortran or assembler language routine
to a Fortran library routine with a name that is the same as the name
of a C/C++ library
routine. The reference is considered to be a conflicting reference
only when the intended resolution is to the Fortran library routine
rather than to the corresponding C/C++ library
routine.
- constructed reentrancy
- The attribute of applications that contain external data and require
additional processing to make them reentrant. Contrast with natural
reentrancy.
- control block
- A storage area used by a computer program to hold control information.
- control section (CSECT)
- The part of a program specified by the programmer to be a relocatable
unit, all elements of which are to be loaded into adjoining main storage
locations.
- control statement
- In programming languages, a statement that is used to alter the
continuous sequential execution of statements; a control statement
can be a conditional statement, such as IF, or an imperative statement,
such as STOP. In JCL, a statement in a job that is used in identifying
the job or describing its requirements to the operating system.
- conversational monitor system (CMS)
- A virtual machine operating system that provides general interactive
time sharing, problem solving, and program development capabilities,
and operates only under the control of the VM/370 control program.
- CPPL
- Command processor parameter list.
- CSECT
- Control section.
- cumulative service tape
- A tape sent with a new function order, containing all current
PTFs for that function.
- cursor
- One of two pointers managed by the condition manager as it processes
a condition. See handle cursor and resume cursor.
- Custom-Built Installation Process Offering (CBIPO)
- A CBIPO is a tape that has been specially prepared with the products
(at the appropriate release levels) requested by the customer. A CBIPO
simplifies installing various products together.
- Custom-Built Product Delivery Offering (CBPDO)
- A CBPDO is a tape that has been specially prepared for installing
a particular product and the related service requested by the customer.
A CBPDO simplifies installing a product and the service for it.
- Customer Information Control System (CICS)
- CICS is an OnLine Transaction
Processing (OLTP) system that provides specialized interfaces to databases,
files and terminals in support of business and commercial applications.
- CWI
- Compiler-writer interface.
- dangling pointer
- A pointer to storage that has been freed.
- data, qualifying
- See qualifying data.
- data aggregate
- A logical collection of data elements that can be referred to
either collectively or individually. In PL/I, an
array or a structure.
- data division
- In COBOL, the part of a program that describes the files to be
used in the program and the records contained within the files. It
also describes any WORKING-STORAGE data items, LINKAGE SECTION data
items, and LOCAL-STORAGE data items that are needed.
- data set
- Under MVS, a named collection
of related data records that is stored and retrieved by an assigned
name. Equivalent to a CMS file.
- data type
- The properties and internal representation that characterize data.
- datum, qualifying
- A single element of qualifying data associated with a condition.
See qualifying data.
- DBCS
- Double-byte character set.
- DB2®
- DATABASE 2; generally, one of a family of IBM relational database management systems and,
specifically, the system that runs under MVS.
- DCLCB
- Declare control block.
- DCT
- Destination control table.
- DD statement
- In MVS, the data definition
statement. A JCL control statement that serves as the connection between
a file's logical name (the ddname) and the file's physical name (the
data srt name).
- ddname
- Data definition name. The logical name of a file within an application.
The ddname provides the means for the logical file to be connected
to the physical file through a FILEDEF command, DD statement, or ALLOCATE
command. DD statement or ALLOCATE command.
- decimal overflow
- A condition that occurs when one or more nonzero digits are lost
because the destination field in a decimal operation is too short
to contain the results.
- declare control block (DCLCB)
- Control block containing file information.
- default
- A value that is used or an action that is taken when no alternative
is specified.
- dereference
- In C, the application of the unary operator (*) to a pointer to
access the object the pointer points to. Also known as indirection.
- descriptor
- PL/I control
block that holds information such as string lengths, array subscript
bounds, and area sizes, and is passed from one PL/I routine
to another during run time.
- descriptor, q_data
- See q_data descriptor.
- destination control table (DCT)
- In CICS, a table containing
an entry for each extrapartition, intrapartition, and indirect destination.
Extrapartition entries address data sets external to the CICS region. Indirect destination entries redirect
data to a destination controlled by another DCT entry. Intrapartition
destination entries contain the information required to locate the
queue in the intrapartition data set.
- device
- A computer peripheral or an object that appears to the application
as such. [POSIX.1]
- direct argument passing
- A type of parameter passing in which the value of the argument
is placed directly in the argument list body.
- directory entry
- An object that associates a filename with a file. Several directory
entries can associate names with the same file. [POSIX.1]
- disabled/enabled
- See enabled/disabled.
- distribution libraries
- IBM-supplied partitioned data sets on tape containing one or more
components that the user restores to disk for subsequent inclusion
in a new system.
- distribution zone
- In SMP/E, a group of VSAM records that describe the SYSMODs and
elements in the distribution libraries.
- double-byte character set (DBCS)
- A collection of characters represented by a 2-byte code.
- downward-growing stack
- With Extra Performance Linkage (XPLINK), a stack that grows from
high addresses to low addresses in memory.
- downwardly compatible
- The ability of applications that have been compiled and linked
with Language Environment to
run on previous releases of OS/390®.
In order for an application to be downwardly compatible, it must
not have exploited any new Language Environment function
unavailable in the targeted release.
- double-precision
- Pertaining to the use of two computer words to represent a number
in accordance with the required precision. See also precision,
single-precision.
- doubleword
- A sequence of bits or characters that comprises eight bytes (two
4-byte words) and is referenced as a unit.
- doubleword boundary
- A storage location whose address is evenly divisible by 8.
- driving system
- The system used to install the program. Contrast with target system.
- DSA
- Dynamic storage area.
- dummy argument
- The Fortran term for the data received by a called routine. See
also actual argument.
- dynamic call
- A call that results in locating a called routine at run time,
that is, by loading the routine into virtual storage. Contrast with static
call.
- dynamic loading
- See dynamic call.
- dynamic storage
- Storage acquired as needed at run time. Contrast with static
storage.
- dynamic storage area (DSA)
- An area of storage obtained during the running of an application
that consists of a register save area and an area for automatic data,
such as program variables. DSAs are generally allocated within Language Environment–managed
stack segments. DSAs are added to the stack when a routine is entered
and removed upon exit in a last in, first out (LIFO) manner. In Language Environment, a DSA
is also known as a stack frame.
- EBCDIC
- Extended binary-coded decimal interchange code.
- EIB
- EXEC interface block.
- enabled/disabled
- A condition is enabled when its occurrence will result in the
execution of condition handlers or in the performance of a standard
system action to handle the condition as defined by Language Environment.
A
condition is disabled when its occurrence is ignored by the condition
manager.
- enablement
- The determination by a language at run time that an exception
should be processed as a condition. This is the capability to intercept
an exception and to determine whether it should be ignored or not;
unrecognized exceptions are always defined to be enabled. Normally,
enablement is used to supplement the hardware for capabilities that
it does not have and language enforcement of a language’s semantics.
An example of supplementing the hardware is the specialized handling
of exponent-overflow exceptions based on language standards.
- enablement step
- The first step of the Language Environment condition
handling model. In the enablement step it is determined whether an
exception is to be enabled and processed as a condition. See
also condition step and termination imminent step.
- enclave
- In Language Environment,
an independent collection of routines, one of which is designated
as the main routine and is invoked first. An enclave is roughly analogous
to a program or run unit. an executable program.
- enterprise
- The composite of all operational entities, functions, and resources
that form the total business concern.
- entry name
- In assembler language, a programmer-specified name within a control
section that identifies an entry point and can be referred to by any
control section. See also entry point.
- entry point
- The address or label of the first instruction that is executed
when a routine is entered for execution. Within a load module, the
location to which control is passed when the load module is invoked.
- entry point name
- The symbol (or name) that represents an entry point. See also entry
point.
- environment
- A set of services and data available to a program during execution.
In Language Environment,
environment is normally a reference to the runtime environment of
HLLs at the enclave level.
- environment variable
- A variable that is included in the current software environment
and is therefore available to any called program that requests it.
- epilog
- Code generated at the end of a routine, normally causing a return
to the caller of the routine.
- euro
- The monetary unit of the European Monetary Union (EMU) that was
introduced alongside national currencies on 01 January 1999.
- EuroReady product
- A product is EuroReady if the product, when used in accordance
with its associated documentation, is capable of correctly processing
monetary data in the euro denomination, respecting the euro currency
formatting conventions (including the euro sign). This assumes that
all other products (for example, hardware, software, and firmware)
that are used with this product are also EuroReady. IBM hardware products that are EuroReady may
or may not have an engraved euro sign key on their keyboards.
- EXEC interface block (EIB)
- In CICS, a control block
containing information useful in the execution of an application,
such as a transaction identifier and a time and a date when the transaction
is started.
- exception
- The original event such as a hardware signal, software detected
event, or user-signaled event which is a potential condition. This
action may or may not include an alteration in a program's normal
flow. See also condition.
- execution time
- Synonym for run time.
- execution environment
- Synonym for runtime environment.
- extended binary-coded decimal interchange code (EBCDIC)
- A set of 256 8-bit characters.
- exponent-overflow exception
- The program interruption that occurs when an overflow occurs during
the execution of a floating-point instruction, that is, when the result
value from the instruction has a characteristic that is larger than
the floating-point data format can handle.
- exponent-underflow exception
- The program interruption that occurs when the result value from
executing a floating-point instruction has a nonzero fraction and
a characteristic is smaller than the floating-point data format can
handle. This program interruption can be disabled through a program
mask bit setting.
- extended error handling facility
- The VS FORTRAN facility
that provided automatic error correction and control over both the
handling of the errors and the printing of error messages.
- external data
- Data that persists over the lifetime of an enclave and maintains
last-used values whenever a routine within the enclave is reentered.
Within an enclave consisting of a single load module, it is equivalent
to any C data objects that have static storage duration, a Fortran
common block, and COBOL EXTERNAL data.
- external reference
- In an object module, a reference to a symbol, such as an entry
point name, defined in another program or module.
- Extra Performance Linkage (XPLINK)
- Extra Performance Linkage (XPLINK) is an
enhanced linkage between programs that can significantly improve the
performance of your C and C++ programs. The primary goal of XPLINK is to
make subroutine calls as fast and efficient as possible by removing
all nonessential instructions from the main program path. The XPLINK runtime
option controls the initialization of the XPLINK environment.
- FCB
- File control block.
- feature
- A part of an IBM product
that may be ordered separately by a customer.
- feature code
- A four-digit code used by IBM to
process hardware and software orders.
- feedback code (fc)
- A condition token value. If you specify fc in
a call to a callable service, a condition token indicating whether
the service completed successfully is returned to the calling routine.
- fetch
- The dynamic load of a PL/I procedure.
- FIB
- File information block.
- file
- A named collection of related data records that is stored and
retrieved by an assigned name. Equivalent to an MVS data set.
- file control block (FCB)
- Block containing the addresses of I/O routines, information about
how they were opened and closed, and a pointer to the file information
block.
- FILEDEF
- File definition statement.
- file definition statement (FILEDEF)
- In CMS, serves as the connection between the logical name of a
file and the physical name of a file.
- file descriptor
- A per-process unique, nonnegative integer used to identify an
open file for the purpose of file access. [POSIX.1]
- file information block (FIB)
- A read-only block describing the characteristics of an I/O file.
- file system
- A collection of files and certain of their attributes. A file
system provides a name space for file serial numbers referring to
those files.
- file tag
- For Enhanced ASCII functionality, a file attribute that identifies
the character set of the text data within a file and indicates whether
the file is eligible for automatic conversion. See also automatic
conversion and coded character set ID (CCSID).
- fix
- A correction of an error in a program, usually a temporary correction
or bypass of defective code.
- fix-up and resume
- The correction of a condition either by changing the argument
or parameter and running the routine again or by providing a specific
value for the result.
- fixed decimal
- See packed decimal format.
- fixed-point overflow exception
- A program interruption caused by an overflow during signed binary
arithmetic or signed left-shift operations. This program interruption
can be disabled through a program mask bit setting.
- floating point control register (FPC register)
- For IEEE, a floating point control register.
- FMID
- Function modification identifier.
- Fortran
- A high-level language used primarily for applications involving
numeric computations. In previous usage, the name of the language
was written in all capital letters, that is, FORTRAN.
- Fortran signature CSECT
- The resident routine that indicates that the load module in which
it is present contains a Fortran routine.
- FORTRAN 66
- The FORTRAN language standard formally known as American National
Standard FORTRAN, ANSI X3.9-1966. This language standard specifies
the form and establishes the interpretation of programs written to
conform to it.
- FORTRAN 77
- The FORTRAN language standard formally known as American National
Standard FORTRAN, ANSI X3.9-1978. This language standard specifies
the form and establishes the interpretation of programs written to
conform to it.
- FPC
- See floating point control register (FPC register).
- fullword
- A sequence of bits or characters that comprises four bytes (one
word) and is referenced as a unit.
- fullword boundary
- A storage location whose address is evenly divisible by 4.
- function
- A routine that is invoked by coding its name in an expression.
The routine passes a result back to the invoker through the routine
name.
- function modification identifier (FMID)
- The value used to distinguish separate parts of a product. A product
tape or cartridge has at least one FMID.
- GET
- Global error table.
- global error table (GET)
- A method employed by some HLLs, for
example, C and Fortran, to determine
actions for handling conditions. Whereas Language Environment condition
handling actions are defined at the stack frame level, actions defined
using the global error table apply to an entire application until
explicitly changed. See also extended error handling facility.
- Gregorian calendar
- The calendar in use since Friday, 15 October 1582 throughout most
of the world. Used as the basis for the Lilian date used in
many Language Environment date
and time services.
- GTAB table
- Table in C/370™ containing
error information.
- handle cursor
- A pointer used by the condition manager as it traverses the stack.
The handle cursor points to the condition handler currently being
invoked in the stack frame, whether it be a user-written condition
handler or an HLL-specific condition handler.
- handled condition
- A condition that either a user-written condition handler or the
HLL-specific condition handler has processed and for which the condition
handler has specified that execution should continue.
- handler
- See condition handler.
- header file
- A file that contains system-defined control information that precedes
user data.
- heap 0
- Synonymous with initial heap.
- heap
- An area of storage used for allocation of storage whose lifetime
is not related to the execution of the current routine. The heap consists
of the initial heap segment and zero or more increments. See anywhere
heap, below heap, initial heap, and additional heap.
- heap element
- A contiguous area of storage allocated by a call to the CEEGTST
service. Heap elements are always allocated within a single heap segment.
- heap increment
- See increment.
- heap pool
- A storage pool that, when used by the storage manager, can be
used to improve the performance of heap storage allocation. This can
improve the performance of a multi-threaded application.
- heap segment
- A contiguous area of storage obtained directly from the operating
system. The Language Environment storage
management scheme subdivides heap segments into individual heap elements.
If the initial heap segment becomes full, Language Environment obtains
a second segment, or increment, from the operating system.
- heap storage
- See heap.
- heavy weight thread
- A heavy weight thread has a one-to-one correspondence with an MVS task control block (TCB) in that
the lifetime of the thread is the lifetime of the TCB. [POSIX.1]
- hexadecimal
- A base 16 numbering system. Hexadecimal digits range from 0 through
9 (decimal 0 to 9) and uppercase or lowercase A through F (decimal
10 to 15) and A through F, giving values of 0 through 15.
- high-level language (HLL)
- A programming language above the level of assembler language and
below that of program generators and query languages. Examples are
C, C++,
COBOL, Fortran, and PL/I.
- HLL
- High-level language.
- hook
- The location in a compiled program where the compiler inserts
an instruction that allows the user to later interrupt the program
(by setting breakpoints) for debugging purposes.
- IBM service representative
- An individual in IBM who
performs maintenance services for IBM products
or systems.
- IBM Software Distribution
(ISD)
- The IBM department responsible
for software distribution.
- IBM Support Center
- The IBM department responsible
for software service.
- IBM systems engineer (SE)
- An IBM service representative
who performs maintenance services for IBM software
in the field.
- implementation defined
- An indication that the implementation defines and documents the
requirements for correct program constructs and correct data of a
value or behavior. [POSIX.1]
- ILC
- Interlanguage communication.
- IMS
- Information Management System, IBM licensed
product. IMS supports hierarchical
databases, data communication, translation processing, and database
backout and recovery.
- increment
- The second and subsequent segments of storage allocated to the
stack or heap.
- indirect argument passing
- The body of the argument list contains a pointer to the argument
value.
- indirection
- See dereference.
- initial heap
- The Language Environment heap
controlled by the HEAP runtime option and designated by a heap_id of
0. The initial heap contains dynamically allocated user data. See
also additional heap.
- initial heap segment
- The first heap segment. A heap consists of the initial heap segment
and zero or more additional segments or increments.
- Initial process thread (IPT)
- See initial thread.
- initial program load (IPL)
- The process of loading system programs and preparing a system
to run jobs.
- initial stack segment
- The first stack segment. A stack consists of the initial stack
segment and zero or more additional segments or increments.
- initial thread
- In terms of POSIX, either the thread established by the fork() that
created the process, or the first thread that calls main() after
an exec. Also known as initial process thread
(IPT). [POSIX.1]
- input procedure
- A set of statements, to which control is given during the execution
of a SORT statement, for the purpose of controlling the release of
specified records to be sorted.
- instance-specific information (ISI)
- Located within the Language Environment condition
token, information used by a condition handler or the condition manager
to interpret and react to a specific occurrence of a condition. Qualifying
data is an example of instance-specific information.
- integer
- A positive or negative whole number or zero.
- interactive
- Pertaining to a program or system that alternately accepts input
and responds. In an interactive system, a constant dialog exists between
user and system. Contrast with batch.
- interactive problem control system (IPCS)
- A component of z/OS that permits
online problem management, interactive problem diagnosis, online debugging
for disk-resident CP abend dumps, problem tracking, and problem reporting.
- Interactive System Productivity Facility (ISPF)
- A dialog manager for interactive applications. It provides control
and services to permit execution of dialogs.
- interface validation exit
- A routine that, when used with the binder, automatically resolves
conflicting references within Fortran routines.
- interlanguage communication (ILC)
- The ability of routines written in different programming languages
to communicate. ILC support allows the application writer to readily
build applications from component routines written in a variety of
languages.
- interrupt
- A suspension of a process, such as the execution of a computer
program, caused by an event external to that process, and performed
in such a way that the process can be resumed.
- interruption
- Synonym for interrupt.
- IPCS
- Interactive problem control system
- IPL
- Initial program load.
- ISI
- Instance specific information.
- ISPF
- Interactive System Productivity Facility.
- JCL
- Job control language.
- job control language (JCL)
- A sequence of commands used to identify a job to an operating
system and to describe a job’s requirements.
- job step
- The job control (JCL) statements that request and control execution
of a program and that specify the resources needed to run the program.
The JCL statements for a job step include one EXEC statement, which
specifies the program or procedure to be invoked, followed by one
or more DD statements, which specify the data sets or I/O devices
that might be needed by the program.
- Julian date
- A date format that contains the year in positions 1 and 2, and
the day in positions 3 through 5. The day is represented as 1 through
366, right-adjusted, with zeros in the unused high-order position.
- kernel
- The part of the component that contains programs for such tasks
as I/O, management, and communication.
- KSDS
- Key-sequenced data set. See also VSAM.
- L-name
- In C,
this is a mixed-case external identifier that is up to 255 characters
long. See also S-name.
- Language Environment
- Short form of z/OS Language Environment.
A set of architectural constructs and interfaces that provides a common
runtime environment and runtime services for C, C++, COBOL,
Fortran, PL/I, and Java™ applications
compiled by Language Environment-conforming
compilers.
- Language Environment-conforming
- Adhering to Language Environment's common
interface conventions.
- Language Environment-enabled
- A program that has been link-edited with the routines or stubs
provided with Language
Environment.
- language-sensitive editing
- A set of editing functions that are responsive to the programming
language, syntax, and environment of source programs as they are being
edited. Typical language-sensitive editing features are automatic
indenting, token highlighting, syntax checking, and language-sensitive
help.
- LIBPACK
- A collection of individual modules that are packaged into a single
load module in order to reduce the time that would otherwise be needed
to load the individual load modules.
- library
- A collection of functions, subroutines, or other data.
- library latch
- An object similar to a mutex and used within the Language Environment library
to synchronize access to resources shared among threads.
- library vector table (LIBVEC)
- A vector table used to support access to library routines (Language Environment and HLLs)
from compiler-generated code, user-written assembly language code,
and other subroutines.
- library workspace (LWS)
- Special register save areas for certain PL/I library routines,
preallocated in nonstack storage.
- LIBVEC
- Library vector table.
- LIFO
- Last in, first out method of access. A queuing technique in which
the next item to be retrieved is the item most recently placed in
the queue.
- Lilian date
- The number of days since the beginning of the Gregorian calendar.
Day one is Friday, 15 October 1582. The Lilian date format is named
in honor of Luigi Lilio, the creator of the Gregorian calendar.
- link pack area (LPA)
- In MVS, an area of main storage
containing reenterable routines from system libraries. Their presence
in main storage saves loading time when a reenterable routine is needed.
- link-edit
- To create a loadable computer program by means of a linkage editor
or binder.
- linkage editor
- An operating system component that resolves cross-references between
separately compiled or assembled modules and then assigns final addresses
to create a single relocatable load module. The linkage editor then
stores the load module in a load library on disk.
- linked list
- A list in which the data elements may be dispersed but in which
each data element contains information for locating the next. Synonymous
with chained list.
- load module
- A collection of one or more routines that have been stored in
a library by the linkage or binder after having been compiled or assembled.
External references have usually been—but are not necessarily—resolved.
When the external references have been resolved, the load module is
in a form suitable for execution.
- local data
- Data that is known only to the routine in which it is declared.
Equivalent to local data in C and both WORKING-STORAGE and LOCAL-STORAGE
in COBOL.
- locale
- An identifer that determines the way in which data is processed,
printed, and displayed in a particular user community. A locale includes
conventions for a specific language and culture, with appropriate
numeric representation, date and time formatting, and monetary formatting.
- locator
- PL/I control
block that holds the address of data such as structures or arrays
and the address of the descriptor.
- LPA
- Link pack area.
- LWS
- Library workspace.
- machine readable
- Pertaining to data a machine can acquire or interpret (read) from
a storage device, a data medium, or other source.
- main program
- The first routine in an enclave to gain control from the invoker.
In Fortran,
a main program does not have a FUNCTION, SUBROUTINE, or BLOCK DATA
statement as its first statement. It could have a PROGRAM statement
as its first statement. Contrast with subprogram.
- main task
- In the context of MVS multitasking
and the C Multitasking
Facility (MTF), the main program in a multitasking environment. The
main task runs the main task program.
- main task program
- In the context of MVS multitasking
and the C Multitasking
Facility (MTF), the part of a program that controls overall processing.
The main task program is run by the main task.
- mapped condition
- A condition that is generated by one component and converted,
or mapped, to another component; for example, some Language Environment conditions,
such as attention interrupts or the decimal divide condition, map
directly to the PL/I ATTENTION
and ZERODIVIDE conditions, respectively.
- megabyte (MB)
- 1,048,576 bytes.
- medium weight thread
- A medium weight thread has a one-to-one correspondence with an MVS TCB except the lifetime of the
TCB may exceed the lifetime of the thread. [POSIX.1]
- memory file control block (MFCB)
- Block residing at thread level in C/370 containing
the memory information about the file.
- MFCB
- Memory file control block.
- microfiche
- A sheet of microfilm capable of containing microimages in a grid
pattern, usually containing a title that can be read without magnification.
- module
- A language construct that consists of procedures or data declarations
and can interact with other such constructs. In PL/I, an
external procedure.
- MTF
- Multitasking Facility.
- multilevel security
- Allows the classification of data and users based on a system
of hierarchical security levels, combined with a system of non-hierarchical
security categories. The security administrator classifies users and
data, and the system then imposes mandatory access controls restricting
which users can access data, based on a comparison of the classification
of the users and the data.
- Multitasking Facility (MTF)
- Facility provided separately by C and by
Fortran to improve turnaround time on multiprocessor configurations
by using MVS multitasking facilities.
MTF is provided by C library
functions or by Fortran callable services.
- multitasking
- A mode of operation in which two or more tasks can be performed
at the same time.
- multithreading
- A mode of operation in which the operating system can run different
parts of a program, called threads, simultaneously.
- mutex
- A mutual exclusive variable that is intended to serialize access
to a shared data object for a short duration of time. [POSIX.1]
- MVS
- Multiple Virtual Storage operating system.
- n-way ILC application
- An ILC application that includes three or more of the following:
a C routine, a COBOL program, a Fortran program, and a PL/I routine.
- NAB
- Next available byte.
- name scope
- The portion of an application within which a particular declaration
of external data applies or is known.
- name space
- The portion of a load module within which a particular declaration
of external data applies or is known.
- named heap
- A heap set up specifically by the CEECRHP callable service. An
identifier is returned when the heap is created.
- national language support
- Translation requirements affecting parts of licensed programs;
for example, translation of message text and conversion of symbols
specific to countries.
- natural reentrancy
- The attribute of applications that contain no static external
data and do not require additional processing to make them reentrant.
Contrast with constructed reentrancy.
- nested condition
- A condition that occurs during the handling of another, previous
condition. Language Environment by
default permits 10 levels of nested conditions. This setting may be
changed by altering the DEPTHCONDLMT runtime option.
- nested enclave
- A new enclave created by an existing enclave. The nested enclave
that is created must be a new main routine within the process. See
also child enclave and parent enclave.
- nested program
- In COBOL, a program that is directly contained within another
program.
- next available byte (NAB)
- The address of the next available byte of storage on a doubleword
boundary. This address is a segment of stack storage.
- next sequential instruction
- The next instruction to be executed in the absence of any branch
or transfer of control.
- nonreentrant
- A type of program that cannot be shared by multiple users.
- null
- Empty, having no meaning.
- null character
- A character that represents X'00'.
- null string
- A string containing no element. A character or bit string with
a length of zero.
- object module
- A collection of one or more control sections produced by an assembler
or compiler and used as input to the linkage editor or binder. Synonym
for text deck or object deck.
- offset
- The number of measuring units from an arbitrary starting point
in a record, area, or control block, to some other point.
- omitted parameter
- A parameter not needed in a call.
- online
- Pertaining to a user's ability to interact with a computer. Pertaining
to a user's access to a computer via a terminal.
- OpenExtensions
- VM/ESA services that support an environment within which operating
systems, servers, distributed systems, and workstations share common
interfaces. OpenExtensions supports standard application development
across multi-vendor systems. It is required if you want to create
and use VM/ESA applications that conform to the POSIX standard.
- operating system
- Software that controls the running of programs; in addition, an
operating system may provide services such as resource allocation,
scheduling, input/output control, and data management.
- OS PL/I
- See PL/I.
- out-of-storage condition
- A condition signaled when an application has used all of the storage
allocated to it. If the STORAGE runtime option is set to a value other
than 0, Language Environment adds
a reserve stack segment to the overflowing stack, and then signals
the out-of-storage condition.
- output procedure
- A set of statements, to which control is given during the execution
of a SORT statement after the sort function is completed, or during
the MERGE statement after the merge function reaches a point at which
it can select the next record in merged order when requested.
- overflow
- Exceeding the capacity of the intended unit of storage. See also fixed-point
overflow exception and exponent-overflow exception.
- overlay
- To write over existing data in storage.
- owning stack frame
- Given the calling sequence of Routine 1 calling Routine 2 that
in turn calls Routine 3, Routine 3 is the owning stack frame if a
condition occurs while Routine 3 is executing.
- ON-unit
- The specified action to be taken upon detection of the condition
named in the containing ON statement.
- packed decimal format
- A format in which each byte in a field except the rightmost digit
represents two numeric digits. The rightmost byte contains one digit
and the sign. For example, the decimal value +123 is represented as
0001 0010 0011 1111.
- pad
- To fill unused positions in a field with dummy data, usually zeros,
ones, or blanks.
- parallel function
- In the context of MVS multitasking
and the C Multitasking
Facility, those portions of a program that can run independently of
the main task program and each other. Subtasks run the
parallel functions.
- parallel program
- In the context of the Fortran parallel facility (not MTF), a program
that uses parallel language constructs, invokes any of the parallel
callable services, or was compiled with the PARALLEL compile-time
option.
- parallel subroutine
- In the context of MVS multitasking
and the Fortran Multitasking Facitity, those portions of a program
that can run independently of the main task program and each other.
The parallel subroutines run in MVS subtasks.
- parameter
- 1) Data items that are received by a routine. 2) The term used
in certain other languages for the Fortran term dummy argument.
See argument, actual argument, and dummy argument.
- parent enclave
- The enclave that issues a call to system services or language
constructs to create a nested (child) enclave. See also child enclave and nested
enclave.
- partition
- A fixed-size division of storage.
- pass by content
- A COBOL argument passing style synonymous with passing an argument
by value (indirect). In this style, R1 contains a pointer to a copy
of the argument.
- pass by reference
- In programming languages, one of the basic argument passing semantics
where the address of the object is passed. Any changes made by the
callee to the argument value will be reflected in the calling routine
at the time the change is made.
- pass by value
- In programming languages, one of the basic argument passing semantics
where the value of the object is passed. Any changes made by the callee
to the argument value will not be reflected in the calling routine.
- percolate
- The action taken by the condition manager when the returned value
from a condition handler indicates that the handler could not handle
the condition, and the condition will be transferred to the next handler.
- picture string
- Character strings used to specify date and time formats.
- PID
- Process ID.
- PL/I
- A general purpose scientific/business high-level language. PL/I
is a high-powered procedure-oriented language especially well suited
for solving complex scientific problems or running lengthy and complicated
business transactions and record-keeping applications.
- pointer
- A data element that indicates the location of another data element.
- portability
- The ability to transfer an application from one platform to another
with relatively few changes to the source code.
- Portable Operating System Interface (POSIX)
- Portable Operating System Interface for computing environments,
an interface standard governed by the IEEE and based on UNIX. POSIX is not a product. Rather, it is
an evolving family of standards describing a wide spectrum of operating
system components ranging from C language and shell interfaces to
system administration.
- POSIX
- Portable Operating System Interface.
- POSIX process
- An address space and single thread of control that executes within
that address space, and its required system resources. A process is
created by another process issuing the fork() function.
The process that issues fork() is known as the parent
process, and the new process created by the fork() is
known as the child process. [POSIX.1]
- POSIX signal
- A mechanism by which a process may be notified of, or affected
by, an event occurring in the system. Examples of such events include
hardware exceptions and specific actions by processes. The term signal is
also used to refer to the event itself. [POSIX.1]
- PPA1 entry point block
- Program Prolog Area. This block contains information about the
compiled module.
- PPA2 entry point block
- An extension of the PPA1 entry point block.
- PPT
- Processing program table.
- precedence
- In programming languages, an order relation defining the sequence
of the application of operations or options.
- precision
- A measure of the ability to distinguish between nearly equal values,
usually with data of different lengths. See also single-precision and double-precision.
- preinitialization
- A facility that allows a routine to initialize the runtime environment
once, perform multiple executions within the environment, then explicitly
terminate the environment.
- Preinitialized Environments for Authorized Programs
- A facility that allows an authorized AMODE 64 application to run z/OS XL C/C++ and Language-Environment
conforming Assembler routines through the use of preinitialized environments.
- pre-Language Environment-conforming
- Any HLL program that does not adhere to Language Environment's common
interface. For example, VS COBOL II, OS/VS COBOL, OS PL/I, C/370 Version
1 and Version 2, VS FORTRAN Version 1, VS FORTRAN Version 2, FORTRAN IV G1, and FORTRAN IV H Extended are
all pre-Language Environment-conforming
HLLs.
- prelinker
- A utility that collects compile-time initialization information
from one or more object modules into a single initialization unit.
In the process, the static external data part is mapped.
- preprocessor
- A routine that examines application source code for preprocessor
statements that are then executed, resulting in the alteration of
the source.
- preventive service planning (PSP)
- The online repository of program temporary fixes (PTFs) and other
service information. This information could affect installation.
- procedure
- In COBOL,
a procedure is a paragraph or section that can only be performed from
within the program. In PL/I, a
named block of code that can be invoked externally, usually via a
call.
- procedure library (PROCLIB)
- A program library in direct access storage with job definitions.
The reader/interpreter can be directed to read and interpret a particular
job definition by an execute statement in the input stream.
- process
- The highest level of the Language Environment program
management model. A process is a collection of resources, both program
code and data, and consists of at least one enclave. See also POSIX
process.
- process ID (PID)
- The unique identifier representing a process. A process ID is
a positive integer that can be contained in the data type pid_t.
A process ID shall not be reused by the system until the process lifetime
ends. In addition, if there exists a process groups whose process
group ID is equal to that process ID, the process ID shall not be
reused by the system until the process group lifetime ends. A process
that is not a system process shall not have a process ID of 1. [POSIX.1]
- processing program table (PPT)
- Contains information about CICS load
modules (whether the module is in storage or not, its language, use
count and entry point address, etc.) needed to complete a transaction.
- program
- See enclave.
- program control data
- In PL/I,
data used to affect how a program runs; that is, any data that is
not string or arithmetic data.
- program interruption
- The interruption of the execution of a program due to some event
such as an operation exception, an exponent-overflow exception, or
an addressing exception.
- program level
- The modification level, release, version, and fix level.
- program management
- The functions within the system that provide for establishing
the necessary activation and invocation for a program to run in the
applicable runtime environment when it is called.
- program mask
- In bits 20 through 23 of the program status word (PSW), a 4-bit
structure that controls whether each of the fixed-point overflow,
decimal overflow, exponent-overflow, and significance exceptions should
cause a program interruption. The bits of the program mask can be
manipulated to enable or disable the occurrence of a program interruption.
- program number
- The seven-digit code (in the format xxxx-xxx) used by IBM to identify each program product.
- program specification block (PSB)
- In IMS/VS, a control block that contains all database program
communication blocks (DB PCB) that exist for a single application
program. DB PCBs define which segments in a database an application
can access.
- program status word (PSW)
- A 64-bit structure that includes the instruction address, program
mask, and other information used to control instruction sequencing
and to determine the state of the CPU. See also program mask.
- program temporary fix (PTF)
- A temporary solution or bypass of a problem diagnosed by IBM as resulting from a defect in
a current unaltered release of the program.
- program unit
- Synonym for compilation unit.
- programmable workstation (PWS)
- A workstation that has some degree of processing capability and
that allows a user to change its functions.
- prolog
- The code sequence when a routine is entered.
- promote
- To change a condition to a different one by a condition handler.
A condition handler routine promotes a condition because the error
needs to be handled in a way other than that suggested by the original
condition.
- PSB
- Program specification block.
- PSP
- Preventive service planning.
- PSW
- Program status word.
- PWS
- Programmable workstation.
- q_data
- Qualifying data. Information that a user-written condition handler
can use to identify and react to a given instance of a condition.
- q_data descriptor
- A qualifying datum that contains the data type and length of the
immediately following qualifying datum associated with a condition
token.
- q_data_token
- An optional 32-bit data object that is placed in the ISI. It is
used to access the qualifying data associated with a given instance
of a condition.
- qualifier
- A modifier that makes a name unique.
- qualifying data
- q_data. Unique information associated through a condition token
with a given instance of a condition. A user-written condition handler
uses qualifying data to identify and react to the condition.
- qualifying datum
- A single element of qualifying data associated with a condition.
See qualifying data.
- reason code
- 1) Return code to CICS only.
2) A value returned to the invoker of an enclave that indicates how
the enclave terminated. The value reflects whether the enclave terminated
successfully, or unsuccessfully, to an unhandled condition.
- recursive routine
- A routine that can call itself or be called by another routine
that it has called.
- reenterable
- reentrant
- reentrant
- The attribute of a routine or application that allows more than
one user to share a single copy of a load module.
- register
- Special processing areas that hold a specific amount of data and
can process, load, and store this data quickly. To specify formally.
In Language Environment,
to register a condition handler means to add a user-written condition
handler onto a routine's stack frame.
- register save area (RSA)
- Area of main storage in which contents of registers are saved.
- regular file
- A file that is a randomly accessible sequence of bytes, with no
further structure imposed by the system. [POSIX.1]
- relative pathname
- A pathname that does not begin with a slash. The predecessor of
the first filename in the pathname is taken to be the current working
directory of the process. [POSIX.1]
- reserved word
- In programming languages, a keyword that may not be used as an
identifier.
- resident modules
- A module that remains in a particular area of storage.
- resident routines
- The Language Environment library
routines linked with your application. They include such things as
initialization routines and callable service stubs.
- resume
- To continue execution in an application at the point immediately
after which a condition occurred. This occurs when a condition handler
determines that a condition has been handled and normal application
execution should continue.
- resume cursor
- The point in an application at which execution should continue
if a condition handler requests the resume action for a condition
it is processing. When a condition is signaled, the resume cursor
is at the location at which the error occurred or at which the condition
was first reported to the condition manager. The resume cursor can
be moved with the CEEMRCE or CEEMRCR callable service.
- return code
- A code produced by a routine to indicate its success or failure.
It may be used to influence the execution of succeeding instructions
or programs.
- return_code_modifier
- A value set by Language Environment routines
to indicate the severity of an unhandled condition. The return_code_modifier
is a component of the return code that indicates the status of the
execution of an enclave.
- RMODE
- Residence mode. Provided by the linkage editor, the attribute
of a load module that specifies whether the module, when loaded, must
reside below the 16MB virtual storage line or may reside anywhere
in virtual storage.
- rollback
- The process of restoring data changed by an application to the
state at its last commit point.
- root load module
- The load module containing a main routine and the first to be
executed in an application.
- routine
- In Language Environment,
refers to a PL/I procedure,
a C function,
a Fortran main
program or subprogram, or a COBOL program
or a separate subroutine.
- RSA
- Register save area.
- run
- To cause a program, utility, or other machine function to be performed.
- RUNCOM
- COBOL block containing the ID and address of the main program.
- run time
- Any instant at which a program is being executed. Synonymous with execution
time.
- runtime environment
- A set of resources that are used to support the execution of a
program. Synonymous with execution environment.
- run unit
- One or more object programs that are executed together. In Language Environment, a run
unit is the equivalent of an enclave.
- safe condition
- Any condition having a severity of 0 or 1. Such conditions are
ignored if no condition handler handles the condition.
- save area
- Area of main storage in which contents of registers are saved.
- SBCS
- Single-byte character set.
- scalar
- A quantity characterized by a single value. Contrast with aggregate.
- scalar instruction
- An instruction, such as a load, store, arithmetic, or logical
instruction, that operates on a scalar. Contrast with vector instruction.
- scope
- A term used to describe the effective range of the enablement
of a condition and/or the establishment of a user-generated routine
to handle a condition. Scope can be both statically and dynamically
defined. The portion of an application within which the definition
of a variable remains unchanged.
- scope terminator
- Variable at the end of a statement.
- segment
- See stack segment.
- severity code
- A part of runtime messages that indicates the severity of the
error condition (1, 2, 3, or 4).
- shared segment
- In VM, a feature of a saved system that allows one or more segments
of reentrant code in real storage to be shared among many virtual
machines.
- shared storage
- An area of storage that is the same for each virtual address space.
Because it is the same space for all users, information stored there
can be shared and does not have to be loaded in the user region.
- shared virtual area (SVA)
- In VSE, a high address area of virtual storage that contains a
system directory list (SDL) of frequently used phases, resident programs
that can be shared between partitions, and an area for system support.
- signal
- In C,
signals are conditions that may or may not be reported during program
execution, depending upon how they are defined to the condition handler.
A condition is registered in C using
the signal() function; a condition is raised using
the raise() function. See also POSIX signal and synchronous
signal. To make the condition manager aware of a condition for
processing.
- signal catching function
- In POSIX, analogous to signal handler. The signal catching
function is specified through the sigaction() function.
[POSIX.1]
- signal handler
- In C,
a function to be called when a signal is reported.
- signature CSECT
- The resident routine that indicates that the load module in which
it is present contains a routine written in a particular language.
- significance exception
- The program interruption that occurs when the resulting fraction
in a floating-point addition or subtraction instruction is zero. This
program interruption can be disabled through a program mask bit setting.
- single-byte character set (SBCS)
- A collection of characters represented by a 1-byte code.
- single-precision
- Pertaining to the use of one computer word to represent a number
in accordance with the required precision. See also precision and double-precision.
- S-name
- In C,
this is a single-case external identifier that is at most eight characters
long. See also L-name.
- softcopy
- One or more files that can be electronically distributed, manipulated,
and printed by a user. Contrasts with hardcopy.
- sort/merge program
- A processing program that can be used to sort or merge records
in a prescribed sequence.
- source code
- The input to a compiler or assembler, written in a source language.
- source program
- A set of instructions written in a programming language that must
be translated to machine language before the program can be run.
- stack
- An area of storage used for suballocation of stack frames. Such
suballocations are allocated and freed on a LIFO (last in, first out)
basis. A stack is a collection of one or more stack segments consisting
of an initial stack segment and zero or more increments.
- stack frame
- The physical representation of the activation of a routine. The
stack frame is allocated on a LIFO stack and contains various pieces
of information including a save area, condition handling routines,
fields to assist the acquisition of a stack frame from the stack,
and the local, automatic variables for the routine. In Language Environment, a stack
frame is synonymous with DSA.
- stack frame collapse
- An action that occurs when the condition manager skips over one
or more active routines and execution resumes in an earlier routine
on the stack. A stack frame collapse happens is an explicit GOTO is
coded in a C or PL/I routine or if the resume cursor is moved with
the CEEMRCR.
- stack increment
- See increment.
- stack segment
- A contiguous area of storage obtained directly from the operating
system. The Language Environment storage
management scheme subdivides stack segments into individual DSAs.
If the initial stack segment becomes full, a second segment or increment
is obtained from the operating system.
- stack storage
- See stack and automatic storage.
- standard system action
- The name given to the language-defined default action taken when
a condition occurs and it is not handled by a condition handler.
- static call
- A call that results in the resolution of the called program during
the link-edit of the application. Contrast with dynamic call.
- static data
- Data that retains its last-used state across calls.
- static storage
- Storage that persists and retains its value across calls. Contrast
with dynamic storage.
- storage heap
- An unordered group of program stack areas that may be associated
with programs running within a process.
- SUBCOM
- Control block containing information about multiple COBOL programs.
- suboption
- A value that can be provided as part of a compile-time or runtime
option to further specify the meaning of the option.
- subpool storage
- All of the storage blocks allocated under a subpool number for
a particular task.
- subprogram
- A program unit that is invoked or used by another program unit.
In Fortran,
a subprogram has a FUNCTION, SUBROUTINE, or BLOCK DATA statement as
its first statement. Contrast with main program.
- SUBSET
- The value that specifies the FMID for a product level.
- subsystem
- A secondary or subordinate system, or programming support, usually
capable of operating independently of or asynchronously with a controlling
system. Examples are CICS and IMS.
- subtask
- In the context of MVS multitasking
and the C Multitasking
Facility (MTF), a task that is initiated and terminated by a higher
order task (the main task). Subtasks run the parallel functions,
those portions of the program that can run independently of the main
task program and each other.
- SVC
- Supervisor call. A request that serves as the interface to certain
functions, such as the allocation of storage.
- symbolic feedback code
- The symbolic representation of the first 8 bytes of the 12-byte
condition token. In a condition-handling routine, a symbolic feedback
code is substituted for the hexadecimal coding of the condition-handling
routine.
- synchronous signal
- A signal attributable to a specific thread. Signals that can be
generated synchronously are SIGABRT, SIGILL, SIGFPE, SIGPIPE, and
SIGSEGV.
- syntax
- The rules governing the structure of a programming language and
the construction of a statement in a programming language.
- system abend
- An abend caused by the operating system’s inability to process
a routine; may be caused by errors in the logic of the source routine.
- systems programming facility
- runtime facilities provided by C that
allow programs to be developed that do not require the Language Environment common
library.
- target libraries
- In SMP/E, a collection of data sets in which the various parts
of an operating system are stored. These data sets are sometimes called
system libraries.
- target zone
- In SMP/E, a collection of VSAM records describing the target system
macros, modules, assemblies, load modules, source modules, and libraries
copied from DLIBs during system generation, and the SYSMODs applied
to the target system.
- task
- In a multiprogramming or multiprocessing environment, one or more
sequences of instructions treated by a control program as an element
of work to be accomplished by a computer.
- task control block (TCB)
- An MVS related control block
which contains information and pointers associated with the task in
process.
- task global table (TGT)
- Table with information about addresses and length of working storage
and the program start address.
- TCB
- Task control block.
- termination imminent step
- The final step of the 3-step Language Environment condition
handling model. In the termination imminent step, user-written condition
handlers and PL/I ON-units
are given one last chance to handle a condition or perform cleanup
before the thread is terminated. See also condition step and enablement
step.
- THDCOM
- Control block with COBOL thread information.
- thread
- The basic runtime path within the Language Environment program
management model. It is dispatched by the system with its own instruction
counter and registers. The thread is where actual code resides.
- thread safe
- A locking mechanism (mutex) that allows a thread to work with
critical data or structures while preventing other threads from gaining
access to the same data or structures. When the thread has finished
processing the critical data or structures, it must release the lock
to allow other threads to gain access to the data or structures. [POSIX.1]
- time sharing option (TSO/E)
- An option on the operating system; for System/370, the option
provides interactive time sharing from remote terminals.
- token
- See condition token.
- trace
- A record of the execution of a computer program. It exhibits the
sequence in which the instructions were executed. To record a series
of events as they occur.
- traceback
- A section of a dump that provides information about the stack
frame (DSA), the program unit address, the entry point of the routine,
the statement number, and status of the routines on the call-chain
at the time the traceback was produced.
- translator
- See CICS translator.
- transient data queue
- A file to which runtime messages are written under CICS. Under Language Environment, the
name of this file is CESE. Also a sequential data set used by the
Folder Application Facility in CICS/MVS to log system messages.
- transient routines
- The Language Environment library
routines that are loaded at run time. Contrast with resident routines.
- translator
- See CICS translator.
- TSO
- TSO/E.
- TSO/E
- Time Sharing Option Extensions. An MVS component
that permits interactive compiling, link-editing, executing, and debugging
of programs.
- UCLIN
- In SMP/E, the command used to initiate changes to SMP/E data sets.
Actual changes are made by subsequent UCL statements.
- underflow
- See exponent-underflow exception.
- unhandled condition
- A condition that isn't handled by any condition handler for any
stack frame in the call chain. Contrast with handled condition.
- UNIX
- See z/OS UNIX System Services.
- unpacked decimal format
- A format for representing numbers in which the digit is contained
in bits 4 through 7 and the sign is contained in bits 0 through 3
of the rightmost byte. Bits 0 through 3 of all other bytes contain
1s (hex F). For example, the decimal value of +123 is represented
as 1111 0001 1111 0010 1111 0011. Synonymous with zoned decimal
format.
- upward-growing stack
- With Extra Performance Linkage (XPLINK), a stack that grows from
low addresses to high addresses in memory.
- upwardly compatible
- The ability for applications that have been linked with Language Environment to
continue to run on later releases of OS/390 Language Environment,
without the need to recompile or relink. Language Environment is guaranteed
to be upwardly compatible.
- user abend
- A request made by user code to the operating system to abnormally
terminate a routine. Contrast with system abend.
- user-written condition handler
- A routine that analyzes and possibly takes action on conditions
presented to it by the condition manager. The condition handler is
registered either by calling the CEEHDLR callable service or by specifying
the USRHDLR runtime option.
- user exit
- A routine that takes control at a specific point in an application.
Two assembler user exits and one HLL user exit are provided by Language Environment. They
are invoked to perform initialization functions and both normal and
abnormal termination functions.
- user heap
- See initial heap.
- usermod
- User modification.
- user stack
- An independent area of stack storage that may be located above
or below 16M, designed to be used by both library routines and compiled
code. See also stack and stack frame.
- vector
- A linearly ordered collection of scalars of the same type. Each
scalar is said to be an element of the vector. See also array.
Contrast with scalar.
- vector instruction
- An instruction, such as a load, store, arithmetic, or logical
instruction, that operates on vectors residing in storage or in a
vector register in the vector facility. Contrast with scalar instruction.
- vendor
- A person or company that provides a service or product to another
person or company.
- virtual origin
- The address of an element in an array whose subscripts are all
zero.
- VO
- Virtual origin.
- void function
- The C representation of a procedure invocation. A void function
is a function that does not return a value.
- VOLSER
- Volume serial number.
- volume
- A certain portion of data, together with its data carrier, that
can be handled conveniently as a unit. A data carrier mounted and
demounted as a unit; for example, a reel of magnetic tape, a disk
pack.
- volume label
- An area on a standard label tape used to identify the tape volume
and its owner. This area is the first 80 bytes and contains VOL 1
in the first four positions.
- volume serial number
- A number in a volume label assigned when a volume is prepared
for use in a system.
- VSAM
- Virtual storage access method. A high-performance mass storage
access method. Three types of data organization are available: entry
sequenced data sets (ESDS), key sequenced data sets (KSDS), and relative
record data sets (RRDS).
- VSTRING
- The VSTRING data type is used for the character string parameters
in many of the Language Environment callable
services. In z/OS Language Environment,
VSTRING is a halfword length-prefixed character string for input,
or a fixed-length 80-character string for output.
- weak external reference
- A special type of external reference that is not to be resolved
by automatic library calls unless an ordinary external reference to
the same symbol is found. The external symbol dictionary entry specifies
the symbol; the location is unknown.
- work registers
- Registers used by the PL/I compiler
as required.
- WORKING-STORAGE
- In COBOL,
the storage required for data items in the WORKING-STORAGE section.
WORKING-STORAGE is a portion of main storage that is used by a computer
program to hold data temporarily.
- workstation
- One or more programmable or nonprogrammable devices that allow
a user to do work on a computer. See also programmable workstation.
- writable static
- In C,
writable static may be any of the following:
- Program variables with the extern storage class
- Program variables with the static storage class
- Writable strings
The Language Environment term
for writable static is external data.
- XPG4
- This term refers to the XPG4 interface standard. The XPG4 standard
is described in detail in X/Open Specification Issue 4.
- XPLINK (Extra Performance Linkage)
- See Extra Performance Linkage.
- zoned decimal format
- Synonym for unpacked decimal format.
- z/OS Language Environment
- An element of z/OS that
provides a common runtime environment and common runtime services
for C/C++, COBOL, PL/I, and Fortran applications.
- z/OS UNIX System Services (z/OS UNIX)
- The set of functions provided by the Shell and Utilities, kernel,
debugger, file system, C/C++ Runtime Library, Language Environment, and other
elements of the z/OS operating
system that allow users to write and run application programs that
conform to UNIX standards.
- 31–bit mode
- See AMODE 31.
- 64–bit virtual mode
- See AMODE 64.
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z/OS Language Environment Concepts Guide
Copyright IBM Corporation 1990, 2014