IBM S/390 Reference Manual page 22

Linux for S/390
Linux for S/390 is a pure Linux operating system that
has the same processing capabilities as Linux that runs
®
on Intel processors, RISC processors, and others. It
has the same characteristics on S/390 that it would on
other platforms, for example it's a pure ASCII environ-
ment. However, it does take advantage of many of the
features of S/390 hardware like IEEE Floating Point and
world class system reliability.
Logical partition.
A subset of the processor hardware that is defined to
support an operating system in LPAR mode.
Logically partitioned (LPAR) mode.
A central electronic complex (CEC) power-on reset
mode that enables use of the PR/SM feature and allows
an operator to allocate CEC hardware resources
(including central processors, central storage,
expanded storage, and channel paths) among logical
partitions. Contrast with basic mode.
Logical String Assist.
This assist consists of three instructions used by the
IBM SAA AD/Cycle C/370™ compiler to improve the
performance of string operations: Compare Logical
String, Move Logical String and Search Logical String.
Microprocessor.
A processor implemented on one or a small number
of chips.
Move Page.
This instruction improves the performance of data
movement between central and expanded storage. It is
required for Hiperbatch, and, if available, is used by
VSAM and SQL/DS™ for improved performance for buff-
ers in hiperspace.
N+1 power supply.
AC and DC power is designed with N+1 redundancy.
Failure of a power thermal component does not cause
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a system outage. Concurrent replacement of a failed
component results in an avoidance of a planned outage.
Multiple Image Facility (MIF).
This facility allows sharing of ESCON channels and Inter-
nal Disk across the PR/SM partitions within a processor.
This can reduce the number of channels, control unit
channel adapters, and ESCON Director ports otherwise
required in order to share control units across LPs. Sup-
port is provided by all ESCON-capable operating sys-
tems.
Multiple Preferred Guest Support.
The capability of VM/ESA to give preferred treatment in
terms of performance and storage for up to six guest vir-
tual machines (such as OS/390, TPF, or VSE/ESA) for pro-
duction use while concurrently running other virtual
machines for test and development. This support
requires the PR/SM feature of S/390 with the processor
running in basic mode. LPAR is not
required and MPG is not supported with VM/ESA
executing in an LPAR.
OS/390 or z/OS image.
A single occurrence of the OS/390 or z/OS operating
system that has the ability to process work.
OS/390 or z/OS system.
An OS/390 or z/OS image together with its associated
hardware, which collectively are often referred to simply
as a system, or OS/390 system.
PR/SM (Processor Resource/Systems Manager).
PR/SM has two modes. In LPAR (logical partition) mode,
a processor is configured into multiple logical images,
each capable of running a separate operating system.
PR/SM Automatic reconfiguration.
The Automatic Reconfiguration Facility (ARF) automates
PR/SM dynamic storage reconfiguration, improving per-
formance during an XRF (Extended Recovery Facility)
Takeover. CICS support is available in CICS/ESA ® .
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