User Manual

SCSI Commands Reference Manual, Rev. J 187
www.seagate.com Direct Access Block commands (SPC-5 and SBC-4)
3.34.4 Command timeouts descriptor
3.34.4.1 Overview
The command timeouts descriptor (see table 157) returns timeout information for commands supported by the logical unit
based on the time from the start of processing for the command to its reported completion.
Values returned in the command timeouts descriptor do not include times that are outside the control of the device server (e.g.,
prior commands with the IMMED bit set to one in the CDB, concurrent commands from the same or different I_T nexuses,
manual unloads, power-on self tests, prior aborted commands, commands that force cache synchronization, delays in the
service delivery subsystem).
For commands that cause a change in power condition, values returned in the command timeouts descriptor do not include the
power condition transition time (e.g., the time to spinup rotating media).
Values returned in the command timeouts descriptor should not be used to compare products.
DESCRIPTOR LENGTH field
The DESCRIPTOR LENGTH field indicates the number of bytes that follow in the command timeouts descriptor.
COMMAND SPECIFIC field
The COMMAND SPECIFIC field contains timeout information (see table 158) that is specific to one or more commands. If no command specific
timeout information is defined by this or the applicable command standard the COMMAND SPECIFIC field is reserved.
Table 157 Command timeouts descriptor format
Bit
Byte
7 6 5 4 3 2 1 0
0 (MSB)
DESCRIPTOR LENGTH (000Ah)
1 (LSB)
2 Reserved
3 COMMAND SPECIFIC
4 (MSB)
NOMINAL COMMAND PROCESSING TIMEOUT. . .
7 (LSB)
8 (MSB)
RECOMMEND COMMAND TIMEOUT. . .
11 (LSB)
Table 158 Command timeout descriptor COMMAND SPECIFIC field usage in this manual
Command Reference
WRITE BUFFER 3.34.4.2