IBM System/370 Operator's Reference Manual page 243

segment table (SGT): A table used in dynamic address translation to control user
access to virtual storage segments. Each entry indicates the length, location, and
availability of a corresponding page table.
segment translation exception: A program interruption that occurs when a virtual
address cannot
be
translated by the hardware because the invalid bit in the segment
table entry for that address is set. See also page translation exception, translation
specification exception.
self-relocating: A programmed routine that is loaded at any doubleword boundary and
can adjust its address values so as to
be
executed at that location.
self-relocating program: A program that is able to run in any area of storage by
having an initialization routine to modify all address constants at object time.
selector channel: A channel designed to operate with only one I/O device at a time.
Once the I/O device is selected, a complete record is transferred one byte at a time.
SEREP: A stand·alone environment recording, editing, and printing program that makes
the data contained in an error logout area of real storage available for further analysis.
Shared Virtual
Area
(SVA): The last part of the virtual system address space that
contains phases which are reenterable and relocatable and which can be shared between
partitions.
simple name: The rightmost component of a qualified name (for example APPLE is
the simple name in TREE.FRUIT.APPLE).
soft stop: A condition in which the CPU has stopped processing but continues to
handle any requested interruptions.
source module: A series of statements which make up the entire input to a single
execution of an assembler or compiler.
stacked job processing: A technique that permits multiple job definitions to be
grouped (stacked) for presentation to the system, which automatically recognizes the
jobs, one after the other.
stand-alone dump: A program that displays the contents of the registers and all of real
storage and that runs independently.
storage block: An area of main storage consisting of 2048 bytes to which a storage
key can
be
assigned.
*
storage protection: An arrangement for preventing access to storage for either read·
ing, or writing, or both.
subtask: A task in which control is initiated by a main task
by
means of a macro
instruction that attaches it.
supervisor: The part of a control program that coordinates the use of resources and
maintains the flow of CPU operations.
supervisor state: The state of CPU operation that allows execution of privileged
instructions. When bit 15 of the PSW is zero, the CPU is in the supervisor state.
SV A: See Shared Virtual Area.
SVC (supervisor call): An instruction which causes an SVC interruption in the hard·
ware to give control to a control program routine (called an SVC routine) for some
specific action, such as reassigning parts of main storage or retrieving data from an I/O
device.
synchronous: Occurring with a regular or predictable time relationship.
SYSIN: A system input stream.
SYSOUT: A system output stream.
system generation (SYSGEN): The process of tailoring the IBM·supplied operating
system to user requirements. 4
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