Adaptec AMM-1572 - Manual (Page 100)

AMM-1570/1572 User’s Guide
Stock Number: 510526-00, Rev. B
Page: Glossary-8
Print Spec Number: 492379-00
Current Date: 3/7/94
ECN Date: 3/8/94
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AMM-1570/1572 User’s Guide
Glossary-8
Scatter/Gather
A device driver feature that
allows the host adapter to mod-
ify the transfer data pointer so
that a single host adapter trans-
fer can transfer to many seg-
ments of memory in a single
transfer, minimizing interrupts
and overhead.
SCB
SCSI Control Block. The mecha-
nism used in Emulation Mode to
transfer control information to
and from the board.
SCSI
Small Computer Systems Inter-
face. A bus interface standard
that defines physical and electri-
cal characteristics for hardware
devices. SCSI provides a stan-
dard interface that enables many
different kinds of devices, such
as disk drives, magneto optical
disks, CD-ROM drives, and tape
drives to interface with the host
computer.
SCSI Bus
One or more SCSI peripheral
devices and a host adapter, con-
nected by cables in a daisy-chain
configuration. The bus may
include both internal and exter-
nal SCSI devices. In systems that
have more than one host
adapter, each adapter has its
own separate SCSI bus.
SCSI Device
A device such as a host adapter
board, fixed disk drive, or CD-
ROM drive that conforms to the
SCSI interface standard and is
attached to a SCSI bus cable. The
device may be an initiator, a tar-
get, or capable of both types of
operation.
SCSI ID
An identifier assigned to SCSI
devices that enables them to
communicate with a computer
when they are attached to a host
adapter via the SCSI bus. Each
SCSI host adapter board has 8
available SCSI IDs with the
numbers 0 through 7. Usually
the host adapter itself is
assigned SCSI ID 7, and fixed
disk devices are assigned to
SCSI IDs 0 and 1.
Single-ended
A term referring to the electrical
characteristics of the signals
used on the SCSI bus interface.
Single-ended signals occupy a
single conductor and are refer-
ences to a common ground car-
ried on the cable between the
SCSI components attached. Most
SCSI devices use single-ended
grounding.
Some SCSI devices use a differen-
tial grounding scheme. These
devices are not supported by the
AMM-1570/1572. Differential
devices may be damaged if you
connect them and the
AMM-1570/1572 to the same
SCSI bus.