EMC Symmetrix DMX-3

EMC Symmetrix DMX-3 Product Guide
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Glossary
I/O device An addressable input/output unit such as a disk drive.
IPL Initial Program Loading.
K
kilobyte (KB) The KB
2
value is based on the convention:
1 KB = 1024 bytes.
The KB
10
value is based on the convention:
1 KB = 1000 bytes.
Although these values are expressed differently, their values are
equivalent
.
L
least recently used
algorithm (LRU)
The algorithm used to identify and make available the global
memory space by removing the least recently used data.
Logical Unit A physical or virtual device addressable through a target. A physical
device can have more than one logical unit.
logical unit number
(LUN)
An encoded three-bit identifier for the logical unit of a SCSI device.
logical volume (LV) A user-defined storage device. In the Symmetrix subsystem, for
example, the user can define a physical disk drive as one to eight
logical volumes.
logical volume
manager (LVM)
Host software responsible for management of the disk subsystems.
Interaction with the LVM is done through GUI or through
stand-alone commands.
long miss A state when requested data is not in global memory and is not in the
process of being fetched.
longitude redundancy
code (LRC)
Exclusive OR (XOR) of the accumulated bytes in the data record.
LPAR Logical Partition or Logical Partitioning Mode. Mainframe system
function that allows different operating systems to run concurrently
in separate logical partitions. See also EMIF.