Seagate Ultra 320 ユーザーズマニュアル

4  

                                                      Parallel SCSI Interface Product Manual, Rev. A 

aborted command—A SCSI command that has been ended by aborting the task created to execute it.

ACA—Auto Contingent Allegiance (see below).

additional sense code—a combination of the ADDITIONAL SENSE CODE and ADDITONAL SENSE CODE 
QUALIFIER in the sense data (see SPC-4)

application client—An object that is the source of SCSI commands. An object in this sense is not a tangible 
piece of hardware, but may be a single numeric parameter, such as a logical unit number, or a complex entity 
that performs a set of operations or services on behalf of another object (see ANSI SAM-4, T10/1683-D).

asynchronous event notification—A procedure used by targets to notify initiators of events that occur when 
a pending task does not exist for that initiator.

asynchronous transfer—An information transfer that uses the REQ/ACK handshake with an offset of zero.

auto contingent allegiance (ACA)—One of the conditions of a task set following the return of a CHECK 
CONDITION status. See Section 4.4.2.

blocked task state—The state of a task that is prevented from completing due to an ACA condition.

blocking boundary—A task set boundary denoting a set of conditions that inhibit tasks outside the boundary 
from entering the Enabled state.

byte—An 8-bit construct.

call—The act of invoking a procedure.

client-server—A relationship established between a pair of distributed objects where one (the client) requests 
the other (the server) to perform some operation or unit of work on the client’s behalf (see SAM-4).

client—An object that requests a service from a server.

command—A request describing a unit of work to be performed by a device server.

Application

Client

Initiator

Task

Manager

Device

Server

Logical

Unit

Target

Device Service Request

Device Service Response

Task Management Request

Task Management Response