Maxtor 10K III User Manual

Maxtor Atlas 10K III 

5-1

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This chapter contains an overview of SCSI command and status processing and a 
detailed description of the commands supported 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.

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The disk drives support the SCSI-3 commands listed in Table 5-1. The command 
categories are sequential, normal, and 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). 

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.

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   

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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