gtpd3m0rLibrary Guide with Master Index and Glossary

O

object
An instantiation of an object class. A coupling facility (CF) list structure or a connection to a CF list structure.

object aggregation
The practice of grouping unrelated objects (in terms of inheritance) together to represent other objects.

object class
A description that defines the exact format of the attributes (data) as well as the exact methods (functions) to be applied to the data. A category of objects.

object code
Machine-executable instructions, usually generated by a compiler from source code written in a higher level language (such as C language).

object file
In the TPF system, a compiler or assembler output file that is suitable as input to a linkage editor. Object files are included in a load module as designated by the build script for the load module.

object header
A header that contains an object ID, update sequence counter, and object length.

object ID
A field containing the hexadecimal class ID of the object. When you find an object in a record using the ZDFIL command, you can determine what class or type of object it is from this class ID. The class IDs of all the objects used by TPF collection support (TPFCS) are defined by CLASSID macro statements in the ITO2 copy segment.

object length
A field containing the length of an object when it is brought into memory by TPF collection support (TPFCS) to process its associated persistent collection.

object module
In the TPF system, an output file produced by a C compiler supported by the TPF system or by the high-level assembler (HLASM) that is ready to be processed by the TPF offline loader, TPFLDR. To create an object module using a C compiler, use the TARGET(TPF) option. To create an object module with HLASM, the source code must call the BEGIN macro with TPFISOC=NO and the FINIS macro.

OCR
Open Systems Adapter (OSA) configuration record.

octal
A base 8 numbering system.

octal constant
The digit 0 followed by any digits 0 to 7.

online multiple release
A multiple release where pool directory update (PDU) processing was run between two or more releases of a pool address. See also multiple release and offline multiple release.

offline ACF/SNA table generation (OSTG)
A function that creates the tables used online to define and control the ACF/SNA network.

offline functions
See offline system.

offline loader
See general file loader, auxiliary loader, or E-type loader.

offline multiple release
A multiple release where pool directory update (PDU) processing was not run between two or more releases of a pool address. See also multiple release and online multiple release.

offline system
The batch-oriented MVS programs that support the online TPF system.

offload device
A device that performs well-defined interface services to free the host processor to perform other tasks.

OLD
A symbolic name, reserved to TPF, for a general tape denoting the load medium to be used by the E-type loader function.

OMT
Output message transmitter.

online loader
See general file loader, auxiliary loader, or E-type loader.

online system
The TPF production system.

on-time event
The signal generated by a Sysplex Timer (STR) that verifies TOD synchronization in the CPC.

open file
A file that is currently associated with a file descriptor. (POSIX.1)

open file description
An object that contains information such as a file offset, the status of a file, and the access mode of a file. An open file description can be referred to by one or more file descriptors.

Open Systems Adapter (OSA)
Integrated hardware that combines the functions of an IBM System/390 input/output (I/O) channel with the functions of a network port to provide direct connectivity between IBM System/390 applications and their clients on the attached networks.

operand
An expression that is acted upon by an operator.

operating system
Software that controls functions such as resource allocation, scheduling, input/output control, and data management.

operation
A specific action such as add, multiply, shift.

operational program zero (OPZERO)
The program that creates an entry control block (ECB), defines an entry, and therefore introduces new message information into the system for processing. It is activated when the CPU loop dispatches a work item from the input list.

operator
A symbol (such as +, -, *) that represents an operation (in this case, addition, subtraction, multiplication).

OPR dump
The dump generated when an ECB-controlled program detects an error condition that does not necessarily stop the ECB from continuing its processing.

optimistic concurrency
In TPF collection support (TPFCS), a way of controlling data access. Optimistic concurrency allows a user to read a collection, update it, and replace it without requiring exclusive access to the collection.

OPZERO
Operational program zero.

ordinal number
For a symbolic file address, the relative position of a record in a record type.

OSA
Open Systems Adapter.

OSA configuration record (OCR)
A record consisting of two tables, the Open Systems Adapter (OSA) definition table and the OSA Internet Protocol (IP) address table, that contain the definitions and status of OSA-Express connections.

OSA control block
A control block that contains one entry for each active OSA-Express connection.

OSA definition table
A table in the Open Systems Adapter (OSA) configuration record that contains the definitions and status of the OSA-Express connections.

OSA-Express
Integrated hardware that uses queued direct I/O (QDIO) to communicate with high-bandwidth networks such as the Gigabit Ethernet (GbE or GENET) or Fast Ethernet (FENET) networks.

OSA IP address table
A table in the Open Systems Adapter (OSA) configuration record that contains the definitions and status of the Internet Protocol (IP) addresses associated with OSA-Express connections.

OSA shared IP address table (OSIT)
A table that contains the status of all Open Systems Adapter (OSA) Internet Protocol (IP) addresses in a loosely coupled TPF complex.

OSIT
Open Systems Adapter (OSA) shared Internet Protocol (IP) address table.

OSTG
Offline ACF/SNA table generation.

out-of-band
The MSG_OOB flag can be set on stream sockets for calls such as send, recv, and recvfrom. The MSG_OOB flag is set for high priority data. Flagged data, which is 1 byte long, may be sent inline with other data or as a single byte by itself. If flagged data is sent inline, it is marked to be read in a specific sequence in relation to the other inline data.

output command handler
A main storage resident program that transmits queued SNA commands.

output message transmitter (OMT)
The program that queues and initiates output message transmission to terminals in an ACF/SNA network.

overflow
A condition that occurs when a portion of the result of an operation exceeds the capacity of the intended unit of storage.