SCSI Description
Quantum Atlas 10K II Ultra160/m SCSI Hard Disk Drives 5–3
5.1 OVERVIEW OF THE SCSI COMMAND DESCRIPTIONS
The disk drives support the SCSI-3 commands listed in Table 5-1. The command
categories are sequential, normal, and immediate.
Immediate commands are processed when received by the drive. In most cases, these
commands do not require drive resources, do not change the state of the drive, and
bypass the command queue (unless the command is tagged).
Sequential commands execute in the order that they arrive (unless accompanied by
a HEAD OF QUEUE tag) and execute to completion before a subsequent command
is activated.
Normal commands are allowed to execute concurrently (with the restriction that the
drive executes overlapping writes in the order received). Normal commands are
usually I/O commands.
Table 5–1 Supported SCSI Commands
Command Operation Code Category
CHANGE DEFINITION 40h Sequential
FORMAT UNIT 04h Sequential
INQUIRY 12h Immediate
LOG SELECT 4Ch Sequential
LOG SENSE 4Dh Sequential
MODE SELECT (6) 15h Sequential
MODE SELECT (10) 55h Sequential
MODE SENSE (6) 1Ah Sequential
MODE SENSE (10) 5Ah Sequential
PERSISTENT RESERVATION IN 5Eh Sequential
PERSISTENT RESERVATION OUT 5Fh Sequential
READ (6) 08h Normal
READ (10) 28h Normal
READ BUFFER 3Ch Sequential
READ CAPACITY 25h Immediate
READ DEFECT DATA (10) 37h Sequential
READ DEFECT DATA (12) B7h Sequential
READ LONG 3Eh Sequential
READ SKIP MASK E8h Normal
REASSIGN BLOCKS 07h Sequential
RECEIVE DIAGNOSTIC RESULTS 1Ch Sequential
(continued…)
