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HP Surestore Disk Array 12h and FC60 User Manual

Page 453

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SIMM (Single In-line Memory Module)

A memory module that provides the local storage (cache) for an SP. An SP must have at
least two 4-MB memory modules to support the storage system cache.

Start Of Day (SOD)

The initialization process used by the disk array controllers to configure itself and
establish various operating parameters. Each controller runs its own SOD process. The
SOD process occurs following a power on reset, or following the insertion of a
controller.

status light

Lights on the front panel of each disk module, power module, and fan used to indicate
the operating status of the hardware.

STM (Support Tools Manager)

A host-based tool used for disk array configuration, management, and diagnostics.

stripe boundary crossing

In disk striping, if the stripe segment size is too small for a single I/O operation, the
operation requires access to two stripes. Called a stripe boundary crossing, this event
reduces I/O performance.

stripe segment size

The amount of information simultaneously read from or written to each disk in a LUN
using disk striping. The default stripe segment size is set to the same value used for
cache page size (4K or 16K). The stripe segment size is configurable and can affect I/O
performance. If the segment size for the LUN is set too small, it may result in many
stripe boundary crossings.

striping (disk striping)

See disk striping.

terminator

An electrical connection at each end of the SCSI bus composed of a set of resistors (or
possibly other components). Its function is to provide a pull-up for open-collector