iSeries

An IBM e(logo)server product that emphasizes integration. It is the successor to the AS/400 family of servers.

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, 210 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.

LMC See licensed machine code.

licensed machine code (LMC)

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.

link-level facility

The ESCON hardware and logical functions of a control unit or channel subsystem that allow communication over an ESCON write interface and an ESCON read interface.

local area network (LAN)

A computer network located on a user’s premises within a limited geographic area.

local e-mail

An e-mail configuration option for storage servers that are connected to a host-system network that does not have a domain name system (DNS) server.

logical address

On an ESCON interface, the portion of a source or destination address in a frame used to select a specific channel-subsystem or control-unit image.

Glossary 339

Page 359
Image 359
IBM DS8000 ISeries, Java Virtual Machine JVM, Key field, Kilobyte KB, Korn shell, Last-in first-out Lifo, Link address