Adaptec 1742A User Manual

Contents

rate and independence of external timing constraints, includingcable length and circuit response times.Asynchronous Event NotificationA process by which a target can send unsolicited sense informa-tion to an initiator using the Send command in order to informthe initiator about the occurrence of an important unusualoccurrence.AT BusThe Industry Standard Architecture bus.Bus Device ResetA SCSI message that clears all activity in the target to which it isaddressed.ByteAn eight-bit unit of data. An octet. A byte is normally the small-est addressable unit of a memory and the unit of transfer on theSCSI bus.CCBSee Command Control BlockCCSSee Common Command SetCDBSee Command Descriptor BlockCommand Control BlockA software object prepared by the host microcomputer softwarefor the host adapter to provide it all the control information itneeds to execute a SCSI command. Abbreviated CCB.Command Descriptor BlockA block of information passed across the SCSI bus to provide thecommand, parameter, and address information necessary for thetarget to execute the desired functions. Prepared by the host soft-ware and placed in the CCB to be passed to the target by the hostadapter. Abbreviated CDB.adaptec AHA-1740A/1742A/1744GL-2