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O E M FUNCTIONAL SPECIFICATION ULTRASTAR XP (DFHC) SSA MODELS 1.12/2.25 GB - 1.0" H I G H
3.6.5 Save Logs and Pointers
The drive periodically saves data in logs in the reserved area of the disks. The information is used by the
drive to support various commands and for the purpose of failure analysis.
Logs are saved every 35 minutes. The amount of time it takes to update the logs varies depending on the
number of errors since the last update. In most cases, updating those logs and the pointers to those logs will
occur in less than 30 milliseconds.
3.6.6 Disk Sweep
The heads are moved to another area of the disk if the drive has not received a command for at least 40
seconds. After flying in the same spot for 9 minutes, the heads are moved to another position. Execution
time is less than 1 full stroke seek.
3.6.7 Summary
Idle Time Function Type
Servo Run Out
Servo Bias ( < 1st hour)
Servo Bias ( > 1st hour)
P F A
Channel Calibration
Save Logs & Pointers
Note: "Re-instruction Period" is the time between consecutive SCSI command requests.
Table 10. Summary of Idle Time Function Performance Impacts
3.7 Command Timeout Limits
The 'Command Timeout Limit' is defined as the time period from when the SCSI_command message is
received by the drive until the corresponding SCSI_status message is transmitted by the drive.
The following times are for environments where Automatic Reallocation is disabled and there are no queued
commands.
Reassignment Time:
The drive should be allowed a minimum of 45 seconds to complete a "Reassign
Blocks" command.
Format Time: The time to complete a "Format Unit" command (with Immed bit = 0) varies by model:
C4x
45 minutes
C2x
25 minutes
C1x
15 minutes
Initiators should also use this time to allow format sequences initiated by "Format Unit" commands (with
Immed bit = 1) to compete and place the drive in a "ready for use" state.
Start/Stop Unit Time: The drive should be allowed a minimum of 30 seconds to complete a "Start/Stop
Unit" command (with Immed bit = 0).
Initiators should also use this time to allow start-up sequences initiated by auto start ups and "Start/Stop
Unit" commands (with Immed bit = 1) to complete and place the drive in a "ready for use" state.
Source filename=PERFORM
USER RESPONSIBLE F O R VERIFYING VERSION A N D COMPLETENESS
Max. Frequency of Occurrence
(minutes)
60/(trk/cyl)
12
60
30/(trk/cyl)
240
35
IBM Corporation
Duration (ms)
Mechanism to Delay/Disable
100
Re-instruction Period
200
Re-instruction Period
200
Re-instruction Period
80
Re-instruction Period / LITF
64
Re-instruction Period
30
Re-instruction Period
Page 49 of 87
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