IBM System/360 Operating Guide

GLOSSARY OF TERMS
Auxiliary Storage (AUX or AS)
1. Any storage media (tape, disk, external
core storage, etc) not contained within the
CPU.
2. An addendum to CPU main storage containing
CPU local storage and multiplexor storage.
Local storage contains the sixteen general-
purpose and the four floating-point registers,
and certain other areas that cannot be
accessed directly by the programmer.
Multiplexor storage contains unit control
words (UCW's) that maintain records of I/O
unit operations.
Central Processing Unit (CPU). This unit contains
the controls, programs, and storage facilities of
the system.
Hexadecimal. A base-sixteen numeric representation
using four bits that are arbitrarily assigned values
of 8, 4, 2, and 1. All bit combinations are valid.
Binary Value
Binary Value
8421 Hex Value
8421 Hex Value
0000
0
1000
8
0001
1
1001
9
0010
2
1010 A
0011
3
1011
B
0100
4
1100
C
0101
5
1101
D
0110
6
1110 E
0111
7 1111
F
Hexadecimal notation is used both for addressing
and arithmetic functions.
Interruption. The interruption system permits the
CPU to change state as a result of conditions ex-
ternal to the system (in input/output units) or in the
CPU itself.
Local Storage. See Auxiliary Storage.
Manual Light. The System/360 Model 30 manual
light is on when the CPU is in the stopped state.
Certain manual operations (such as manual display)
are permitted only when the CPU is in the stopped
state.
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Manual State. In the manual (or stopped) state, the
manual light is on. Instructions are not executed,
and interruptions are not honored.
Mask. A tool used by the programmer either to
allow or inhibit certain interruptions.
Microprogram. A sequence of control operations
within the CPU.
Multiplexor Storage. See Auxiliary Storage.
Operator's Control Panel (OCP). The operator's
control panel section of the system console consists
of those controls normally required to run a job.
These are: the power-on, power-off, interrupt,
and load keys, the load-unit address rotary switches
G, H, and J, and the five lights labeled SYS (system),
MAN (manual), WAIT, TEST, and LOAD.
Problem Program. Any of the class of routines
that perform data proceSSing operations, including
routines that solve problems, monitor and control
industrial processes, sort and merge records,
perform computations, process transactions against
stored records, etc.
Problem State. In this state, all privileged in-
structions are invalid and will cause a program
interruption. When the CPU is in the problem state,
bit 15 of the PSW is on. Problem/supervisor status
is not indicated on the console.
Program Status Word (PSW). The program status
word contains the information required for proper
program operation.
Read-Only Storage (ROS). This storage medium
in the System/360 Model 30 is the control system,
and hence contains the microprograms necessary
to implement the various functions of the system.
Read/Write Storage. Core storage is used as
required in the execution of problem programs.
Some areas of read/write storage are reserved (see
System/360 Principles of Operation, Form A22-6821,
and Ssstem/360 Model 30 Functional Characteristics,
Form A24-3231).
ROS. See Read-Only Storage

IBM System/360 Specifications

General

Brand	IBM
Model	System/360
Category	Desktop
Language	English