IBM System/370 Operator's Reference Manual page 236

error recovery procedures: Procedures designed to help isolate, and, when possible, to
recover from hardware errors in equipment. The procedures are often used in con·
junction with programs that record the statistics of machine malfunctions.
error volume analysis (EVA): With this DOS option, the system issues a message to
the operator when a number of temporary read or write errors (specified by the user
at system generation time) has been exceeded on a currently accessed tape file.
event: An occurrence of significance to a task; typically, the completion of an asyn·
chronous operation, such as input/output.
exchange buffering: A technique using data chaining to avoid moving data in main
storage, in which control of buffer segments and user program work areas is passed
between data management and the user program.
exclusive segments: Segments in the same region of an overlay program, neither of
which is in the path of the other. They cannot be in main storage simultaneously.
execute (EXEC) statement: A job control statement that designates a job step by
identifying the load module to be fetched and executed.
expiration date: A date within a tape label for data protection. The tape cannot be
used as a scratch tape without permission from the operator until this date has ex·
pired.
ex1llnt: The physical locations on input/output devices occupied by or reselVed for a
particular data set.
ex1llnded control mode: When PSW bit 12 is set to 1, the PSW format is changed
from that used for standard System/360 operation: the channel m ... k bits, instruction
length code, and interruption code are removed, and additional mode and mask bits
are included. This is the extended control mode, in which all control registers are
available to the system for control of facilities that are particular to Systemi370.
Abbreviated to EC mode. See also "Basic Control Mode."
extBmal reference: A reference to a symbol defined in another module.
ex1llmal symbol: A control section name, entry point name, or external reference; a
symbol contained in the external symbol dictionary.
exlllmal symbol dictionary (ESD): Control information associated with an object or
load module which identifies the external symbols in the module.
f
F format: A data set record format in which logical records are the same length.
fetch (program): 1. To load requested load modules into main storage, relocating them
as necessary. 2. A control routine that accomplished 1.
File
Protect Mode (FPM):
A
mode of operation that insures maximum protectior,
and
security of customer data. While in file protect mode, the system performs no write
operations and reads no customer data.
fixed page:
A page in real storage that is not to be
paged
out.
F/L Trace (Fetch/Load Trace): Under DOS and TOS, a program that records infor,.,a·
tion about phases and transients as they are called from a core image library.
9
generation data
~p:
A collection of successive, historically related data sets.
GPR (General-purpose register): Temporary storage with capacity of one word. There
are 16 GPRs on System/370 computers. .
GSVC Trace (Generalized Supervisor Calls Trace): A program that records SVC inter·
rupts as they occur. All or
a
selected group of SVCs can be traced.
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