Stock Number: 510647-00, Rev. A Page; Print Spec Number: 492897-00 A; Aaaa Aaaa Aaaa - Adaptec AHA-2740W User Manual

AHA-2740W/2742W/2744W User's Guide
adapter boards, and video
adapters. Expansion devices use
the bus to send data to and
receive data from the PC's CPU
or memory. ISA, EISA, and
®
Micro Channel are the major
bus standards used in PCs.
Bus Device Reset
A SCSI message that clears all
pending activity in the SCSI
peripheral device target to
which it is addressed.
Bus Mastering
A high performance method of
data transfer in which the host
adapter's onboard processor
handles the transfer of data
directly to and from a comput-
er's memory without interven-
tion from the computer's
microprocessor. This is the fast-
est method of data transfer
available for multitasking oper-
ating systems. The
AHA-2740W/2742W/2744W
host adapters use bus mastering.
Byte
An 8-bit unit of data. A byte is
normally the smallest address-
able unit of memory and the
smallest unit of transfer on the
SCSI bus.
C
CCB
See Command Control Block.
CCS
See Common Command Set.
Glossary-2
A AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
A A
AHA-2740W/2742W/2744W User's Guide
A A
A A Stock Number: 510647-00, Rev. A
A
A A Print Spec Number: 492897-00
A A
Current Date: 8/3/94
AAAA AAAA A A AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA
AAAA
CDB
See Command Descriptor Block
Command Control Block
A software object prepared by
the host microcomputer soft-
ware for the host adapter to
provide it all the control infor-
mation it needs to execute a SCSI
command. Abbreviated CCB.
Command Descriptor Block
A block of information passed
across the SCSI bus to provide
the command, parameter, and
address information necessary
for the target to execute the
desired functions. Prepared by
the host software and placed in
the CCB to be passed to the tar-
get by the host adapter. Abbrevi-
ated CDB.
Common Command Set
A de facto standard SCSI com-
mand set for communication
with fixed disk drives. The Com-
mon Command Set (CCS) is the
basis for the SCSI-2 command
set for all types of peripheral
devices.
D
Device Driver
A software program that enables
a PC to communicate with
peripheral devices such as fixed
disk drives and CD-ROM
drives. Each kind of device
requires a different driver.
Device driver programs are
stored on a PC's fixed disk and
Page: Glossary-2
ECN Date: 8/9/94
AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA AAAA
A
A A
A A
A A
A
A A
A A
AAAA AAAA AAAA A A A A