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21.20.4 Medium Access Command Time
The time-out limit for medium access commands that transfer user data or non-user data or both should be a minimum of 30
seconds. These commands are
Pre-Fetch
Read
Read Defect Data
Seek
Send Diagnostic (Function Code = 0)
Read Long
Reassign Blocks
Write
Write and Verify
Write Buffer
Write Same
Verify
Note:
The 30-second limit assumes the absence of bus contention and data transfers of 64 blocks or less. This time should
be adjusted for anticipated bus contention and if longer user data transfers are requested.
21.20.5 Time-out Limits for Other Commands
The drive should be allowed a minimum of 5 seconds to complete these commands:
Inquiry
Log Select
Log Sense
Mode Select
Mode Sense
Persistent Reserve In/Out
Read Buffer
Read Capacity
Read Long
Release
Request Sense
Reserve
Set/Report Device Identifier
Start/Stop Unit (with Immed bit = 1)
Synchronize Cache
Test Unit Ready
Writer Long
The command time-out for a command that is not located at the head of the command queue should be increased by the sum of
command time-outs for all of the commands that are performed before it is.
Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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