Queue tags, Risc core, Scam – LSI SYM22801 User Manual

Page 71: Scatter/gather, Scsi, Scsi-2, Scsi-3, Scsi bus, Scsi device

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Glossary of Terms and Abbreviations

B-5

Queue Tags

A way to keep track of multiple commands that allows for increased
throughput on the SCSI bus.

RAM

Random Access Memory. The computer’s primary working memory in
which program instructions and data are stored and are accessible to the
CPU. Information can be written to and read from RAM. The contents of
RAM are lost when the computer is turned off.

RISC Core

LSI Logic SCSI chips contain a RISC (Reduced Instruction Set
Computer) processor, programmed through microcode scripts.

ROM

Read Only Memory. Memory from which information can be read but not
changed.The contents of ROM are not erased when the computer is
turned off.

SCAM

SCSI Configured AutoMatically. A method to automatically allocate SCSI
IDs via software when SCAM compliant SCSI devices are attached.

Scatter/Gather

A device driver feature that lets the host adapter modify a transfer data
pointer so that a single host adapter transfer can access many segments
of memory. This minimizes interrupts and transfer overhead.

SCSI

Small Computer System Interface. A specification for a high performance
peripheral bus and command set. The original standard is referred to as
SCSI-1.

SCSI-2

The current SCSI specification which adds features the original SCSI-1
standard.

SCSI-3

The next SCSI specification, which adds features to the SCSI-2 standard.
Although this version is still in development, parts of the SCSI-3 standard
are already in use.

SCSI Bus

A host adapter and one or more SCSI peripherals connected by cables
in a linear chain configuration. The host adapter may exist anywhere on
the chain, allowing connection of both internal and external SCSI
devices. A system may have more than one SCSI bus by using multiple
host adapters.

SCSI Device

Any device that conforms to the SCSI standard and is attached to the
SCSI bus by a SCSI cable. This includes SCSI host adapters and SCSI
peripherals.

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