Scsi id, Sdms, Single-ended scsi – LSI SYM22801 User Manual

Page 72: Synchronous data transfer, System bios, Termination, Ultra scsi, Vcci, Virtual memory, Vhdci

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Glossary of Terms and Abbreviations

SCSI ID

A way to uniquely identify each SCSI device on the SCSI bus. Each
SCSI bus has eight available SCSI IDs numbered 0 through 7 (or 0
through 15 for Wide SCSI). The host adapter usually gets ID 7 giving it
priority to control the bus.

SDMS

SCSI Device Management System. A LSI Logic software product that
manages SCSI system I/O.

STA

SCSI Trade Association. A group of companies that cooperate to
promote SCSI parallel interface technology as a viable mainstream I/O
interconnect for commercial computing.

Single-Ended
SCSI

A hardware specification for connecting SCSI devices. It references each
SCSI signal to a common ground. This is the most common method (as
opposed to differential SCSI which uses a separate ground for each
signal).

Synchronous
Data Transfer

One of the ways data is transferred over the SCSI bus. Transfers are
clocked with fixed-frequency pulses. This is faster than asynchronous
data transfer. Synchronous data transfers are negotiated between the
SCSI host adapter and each SCSI device.

System BIOS

Controls the low level POST (Power On Self Test), and basic operation
of the CPU and computer system.

Termination

The electrical connection required at each end of the SCSI bus,
composed of a set of resisters. It improves the integrity of bus signals.

Ultra SCSI

A standard for SCSI data transfers. It allows a transfer rate of up to
20 Mbytes/s over an 8-bit SCSI bus and up to 40 Mbytes/s over a 16-bit
SCSI bus. STA (SCSI Trade Association) supports using the term “Ultra
SCSI” over the term “Fast-20”.

VCCI

Voluntary Control Council for Interference.

Virtual Memory

Space on a hard disk that can be used as if it were RAM.

VHDCI

Very High Density Cable Interconnect. A trapezoidal shielded connector
that has a 0.8 mm pitch.

Wide SCSI

A SCSI-2 feature allowing 16 or 32-bit transfers on the SCSI bus. This
dramatically increases the transfer rate over the standard 8-bit SCSI bus.

Word

A two byte (or 16-bit) unit of information.

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