Glossary

This glossary defines many of the terms and abbreviations used in this publication. If you do not find the term you are looking for, refer to the index or to the Dictionary of Computing, SC20–1699.

access method
The part of the DDM architecture that accepts commands to access and process the records of a file.
alternate index file
A file that has a different key path over a base file. The base file can be a keyed, direct, or sequential file.
API
Application Programming Interface.
CDRA
Character Data Representation Architecture.
data description
Specification of the layout of data. The data description of data stored in a file can be viewed as a file attribute.
data stream
All data transmitted through a data channel in a single read or write operation.
direct file
A file that contains records that have a relationship between the contents of the record and the record position at which the record is stored.
LAN
Local area network.
local area network
LAN.
protocol
A set of rules to be followed by communication systems.
record
The basic unit of data stored in a file and transferred between DDM source and target servers.
sequential file
A file in which records are arranged in exactly the same sequence as they were stored into the file.
source system
A system that requests access to data on another system. It is the “source” of the request.
stream file
Stream files contain strings of bytes that can be accessed according to their relative position within the file.
target system
The system that contains data that is being accessed by another system.
VSAM
Virtual storage access method.