IBM OS/390 User Manual
features to permit a computing system to execute
programs written for another system.
programs written for another system.
emulator. A combination of programming techniques
and special machine features that permits a
computing system to execute programs written for a
different system. See also integrated emulator,
terminal emulator.
and special machine features that permits a
computing system to execute programs written for a
different system. See also integrated emulator,
terminal emulator.
entry-sequenced data set. In OS/390 programs with
VSAM, a data set whose records are loaded without
respect to their contents, and whose relative byte
addresses cannot change. Records are retrieved and
stored by addressed access, and new records are
added at the end of the data set.
VSAM, a data set whose records are loaded without
respect to their contents, and whose relative byte
addresses cannot change. Records are retrieved and
stored by addressed access, and new records are
added at the end of the data set.
error recovery procedures (ERP). Procedures
designed to help isolate and, where possible, to
recover from errors in equipment. The procedures are
often used in conjunction with programs that record
information on machine malfunctions.
designed to help isolate and, where possible, to
recover from errors in equipment. The procedures are
often used in conjunction with programs that record
information on machine malfunctions.
ESCON. Enterprise Systems Connection - A set of
products and services that provides a dynamically
connected environment using optical cables as a
transmission medium.
products and services that provides a dynamically
connected environment using optical cables as a
transmission medium.
ESCON Director. A device that provides connectivity
capability and control for attaching any two links to
each other.
capability and control for attaching any two links to
each other.
Ethernet. A 10-megabit baseband local area network
that allows multiple stations to access the
transmission medium at will without prior
coordination, avoids contention by using carrier sense
and deference, and resolves contention by using
collision detection and transmission. Ethernet uses
carrier sense multiple access with collision detection
(CSMA/CD).
that allows multiple stations to access the
transmission medium at will without prior
coordination, avoids contention by using carrier sense
and deference, and resolves contention by using
collision detection and transmission. Ethernet uses
carrier sense multiple access with collision detection
(CSMA/CD).
event control block (ECB). A control block used to
represent the status of an event.
represent the status of an event.
exit routine. Either of two types of routines:
installation exit routines or user exit routines.
Synonymous with exit program.
installation exit routines or user exit routines.
Synonymous with exit program.
expiration date. The date at which a file is no longer
protected against automatic deletion by the system.
protected against automatic deletion by the system.
extent. Continuous space on a disk or diskette that is
occupied by or reserved for a particular data set, data
space, or file.
occupied by or reserved for a particular data set, data
space, or file.
external side. The receiver of a data entity. A
module or routine that accepts a 2- or 4-digit-date
format entity for further processing from another
module or routine.
module or routine that accepts a 2- or 4-digit-date
format entity for further processing from another
module or routine.
F
file.
•
In PSF/MVS, a member of a partitioned data set
or a sequential data set
or a sequential data set
•
In PSF/VSE, a member in a library.sublibrary
file control table (FCT). A table containing the
characteristics of files processed by CICS file
management.
characteristics of files processed by CICS file
management.
file name. (1) A name assigned or declared for a file.
(2) The name used by a program to identify a file.
(2) The name used by a program to identify a file.
fixed window. A technique to determine the century
(high-order digits) of a year when represented by two
digits. The 2-digit year is compared against a
hardcoded threshold. The century designation is
limited to a 100-year range spanning only two
centuries. For example, assume the threshold is 60,
then if the 2-digit year is
(high-order digits) of a year when represented by two
digits. The 2-digit year is compared against a
hardcoded threshold. The century designation is
limited to a 100-year range spanning only two
centuries. For example, assume the threshold is 60,
then if the 2-digit year is
≥
60, the year is in the 20th
century; if the 2-digit year is
<
60, the year is in the
21st century.
fixed-length record. A record having the same length
as all other records with which it is logically or
physically associated. Contrast with variable-length
record.
as all other records with which it is logically or
physically associated. Contrast with variable-length
record.
foreground partition. In VSE, a space in virtual
storage in which programs are executed under control
of the system. By default, a foreground partition has a
higher processing priority than the background
partition.
storage in which programs are executed under control
of the system. By default, a foreground partition has a
higher processing priority than the background
partition.
formatted dump. A dump in which certain data areas
are isolated and identified.
are isolated and identified.
forward recovery. (1) The reconstruction of a file by
updating an earlier version with data recorded in a
journal. (2) The process of reconstructing a file from a
particular point by restoring a saved version of the
file and then applying changes to that file in the same
order in which they were originally made.
updating an earlier version with data recorded in a
journal. (2) The process of reconstructing a file from a
particular point by restoring a saved version of the
file and then applying changes to that file in the same
order in which they were originally made.
G
GDG. See generation data group.
generation data group (GDG). A feature of the MVS
catalog that allows a collection of data sets to be kept
in chronological order: each data set is called a
generation data set.
catalog that allows a collection of data sets to be kept
in chronological order: each data set is called a
generation data set.
generation data set. One generation of a generation
data group.
data group.
Gregorian calendar. Today
′
s general-use calendar of
12 months and 365 days that employs the current
leap year algorithm (refer to Leap year below).
leap year algorithm (refer to Leap year below).
G l o s s a r y
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