Maxtor Atlas 10K III 5-1
This chapter contains an overview of SCSI command and status processing and a
detailed description of the commands suppor ted by the disk drives. The SCSI
command system enables the initiator to instruct the drive to perform specific
functions.
In this manual, unless otherwise stated, numerical values are given in decimal.
Hexadecimal numbers, such as opcodes, are always given with an “h” following, as in
5Ah except when entire data tables are in hexadecimal.
The disk drives support the SCSI-3 comman ds listed in Table 5-1. The command
categories are sequential, normal, an d 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 com mand queue (unless the com mand is tagged).
Sequential commands execute in the order that they arrive (unless accompanied by
a HEAD OF QUEUE tag) a nd execu te to comple tion bef ore a subs equent command
is activated.
Normal commands are allowed to execute concurrently (with the restriction that the
drive executes overlapping writes in the order received). N ormal comm ands are
usually I/O commands
Supported SCSI Comm an ds
CHANGE DEFINITION 40h Sequentia l
FORMAT UNIT 04h Sequential
INQUIRY 12h Immediate
LOG SELECT 4Ch Sequentia l
LOG SENSE 4Dh Sequential
MODE SELECT (6) 15h Sequential
MODE SELECT (10 ) 55h Sequen ti al
MODE SENSE (6) 1Ah Sequentia l
MODE SENSE (10) 5Ah Sequential
PERSISTENT RESERVATION IN 5Eh Sequentia l