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Glossary
SCSI Device
A device such as a host adapter board, fixed disk drive or CDROM drive that conforms to the SCSI interface standard and is
attached to a SCSI bus cable. The device may be an initiator, a
target, 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
eight 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 references to a common ground carried on
the cable between the SCSI components attached. Most SCSI
devices use single-ended grounding.
Some SCSI devices use a differential grounding scheme. These
devices are not supported by the AHA-2740 Series. Differential
devices may be damaged if you connect them and the AHA-2740
Series to the same SCSI bus.
Single-Threaded Operation
Operation of the computer system such that only one program
can be operating or active at a time. The system must wait until
all resources are available before starting an operation, and it cannot start another operation until the first one is completed.
Small Computer Systems Interface
See SCSI.
Synchronous Data Transfer
A method of data transfer in which data on the SCSI bus is
clocked with fixed-length, fixed-frequency strobe pulses. The acknowledgments may be delayed several clock periods from the
data requests. Synchronous data transfer can be used only for
data transmission on the SCSI bus. It cannot be used for command, message, and status transmission.
Glossary-11
Adaptec AHA-2740 Series User’s Manual
Stock Number: 510381-00 / Rev. C
(Page G-11)
Print Spec Number: 491709-00 Rev C
Current Date: 9/1/93
ECN Date: 9/14/93