IBM DS8000 - ADDITIONAL INFORMATION, Руководство пользователя, Страница: 227 / 250

I/O Configuration Program (IOCP)
A program that defines to a system all the
available I/O devices and channel paths.
I/O device
An addressable read and write unit, such
as a disk drive device, magnetic tape
device, or printer.
I/O interface
An interface that enables a host to
perform read and write operations with
its associated peripheral devices.
I/O Priority Queueing
A facility in the Workload Manager of
System z that enables the system
administrator to set priorities for
queueing I/Os from different system
images. See also multiple allegiance and
parallel access volumes.
I/O processor (IOP)
Controls input-output adapters and other
devices.
I/O sequential response time
The time an I/O request is queued in
processor memory waiting for previous
I/Os to the same volume to complete.
IP See Internet Protocol.
IPL See initial program load.
J
Java Virtual Machine (JVM)
A software implementation of a central
processing unit (CPU) that runs compiled
Java code (applets and applications). (GC)
JVM
See Java Virtual Machine.
K
KB See kilobyte.
key field
The second (optional) field of a count key
data record. The key length is specified in
the count field. The key length determines
the field length. The program writes the
data in the key field and uses the key
field to identify or locate a given record.
The subsystem does not use the key field.
kilobyte (KB)
1) For processor storage, real, and virtual
storage, and channel volume, 2
10
or 1024
bytes.
2) For disk storage capacity and
communications volume, 1000 bytes.
Korn shell
Interactive command interpreter and a
command programming language.
KPOH
See thousands of power-on hours.
L
LAN
See local area network.
last-in first-out (LIFO)
A queuing technique in which the next
item to be retrieved is the item most
recently placed in the queue. (A)
LBA See logical block address.
LCU See logical control unit.
least recently used (LRU)
1) The algorithm used to identify and
make available the cache space that
contains the least-recently used data.
2) A policy for a caching algorithm that
chooses to remove from cache the item
that has the longest elapsed time since its
last access.
LED See light-emitting diode.
licensed machine code
Microcode that IBM does not sell as part
of a machine, but licenses to the customer.
LMC is implemented in a part of storage
that is not addressable by user programs.
Some IBM products use it to implement
functions as an alternate to hard-wired
circuitry.
LIFO See last-in first-out.
light-emitting diode (LED)
A semiconductor chip that gives off
visible or infrared light when activated.
link address
On an ESCON interface, the portion of a
source or destination address in a frame
that ESCON uses to route a frame
through an ESCON director. ESCON
associates the link address with a specific
switch port that is on the ESCON director.
Equivalently, it associates the link address
with the channel subsystem or control
unit link-level functions that are attached
to the switch port.
Glossary
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