LSI 320 User Manual
Page 42
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Glossary of Terms
Copyright © 2002 by LSI Logic Corporation. All rights reserved.
Host
The computer system in which a SCSI host adapter is installed. It uses
the SCSI host adapter to transfer information to and from devices
attached to the SCSI bus.
Host Adapter
A circuit board or integrated circuit that provides a device connection to
the host.
Internal SCSI
Device
A SCSI device installed inside the computer cabinet. These devices are
connected to one another with an unshielded ribbon cable.
PCI and PCI-X
Peripheral Component Interconnect. A high performance local bus
specification that allows connection of devices directly to computer
memory. The PCI Local Bus allows transparent upgrades from a 32-bit
data path at 33 MHz to a 64-bit data path at 33 MHz; from a 32-bit data
path at 66 MHz to a 64-bit data path at 66 MHz; and from a 32-bit data
path at 133 MHz to a 64-bit data path at 133 MHz (1064 Mbytes/s peak).
Peripheral
Device
A piece of hardware (such as a disk drive, printer, or CD-ROM) used with
a computer and under the computer’s control. SCSI peripheral devices
are controlled through a SCSI host adapter.
SCSI Bus
A host adapter and one or more SCSI devices connected by cables in a
linear configuration. The host adapter may exist anywhere on the bus,
allowing connection of both internal and external SCSI devices. A system
may have more than one SCSI bus by using a multi-channel host adapter
or 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, SCSI disk
drives, SCSI CD-ROMS drives, and so on.
SCSI ID
An identifier that addresses specific devices on the SCSI bus and
determins device selection when multiple devices contend for ownership
of the SCSI bus. Wide SCSI buses support SCSI IDs 0 through 15, and
narrow SCSI buses support SCSI IDs 0 through 7. A device gains
ownership of the bus according to the priority of its SCSI ID. The order
of priority, from highest to lowest, is: 7, 6, 5, 4, 3, 2, 1, 0, 15, 14, 13, 12,
11, 10, 9. The host adapter is usually set to the highest priority SCSI ID,
which is SCSI ID 7.
Single-Ended
SCSI
A hardware specification for connecting SCSI devices. It references each
SCSI signal to a common ground. In contrast, differential SCSI uses a
separate ground for each signal.