Adaptec AHA-1740A - Manual (Page 59)

Common Command Set
A de facto standard SCSI command set for communication with
fixed disk drives. The Common Command Set (CCS) is the basis
for the SCSI-2 command set for all types of peripheral devices.
Configuration
The operation of configuring a device on the EISA bus through
access of registers in the device by the host. It replaces the
method of using jumpers common on ISA bus devices.
Control Microprocessor
An integrated circuit computer used to execute the software that
controls the host adapter’s operation.
Device Driver
A program that is linked with, or attached to, an operating sys-
tem to map the software interface of the operating system to the
requirements of attached peripheral devices and host adapters.
Under ASPI, the main component associated with the board is
known as a Manager.
DMA
See Direct Memory Access
Differential
A term referring to the electrical characteristics of the signals
used on the SCSI bus interface. Differential signals occupy two
conductors with a positive (+) and negative (-) polarity component
of the signal. This minimizes the effect of common mode signal
noise and allows the SCSI bus to operate reliably over greater dis-
tances at a higher speed.
Direct Memory Access
A mechanism that allows hardware control of the transfer of
streams of data to or from the main memory of a computing sys-
tem. The mechanism may require setup by the host software.
After initialization, it automatically sequences the required data
transfer and provides the necessary address information.
Disconnect/Reconnect
Disconnect is the function that occurs when a target releases con-
trol of the SCSI bus, allowing the bus to go to the Bus Free phase.
EISA-to-Fast SCSI Host Adapter Glossary
GL-3