Appendix A. SSA Problem Determination Procedures
Problem determination procedures are provided by power-on self-tests (POSTs),
service request numbers (SRNs), and maintenance analysis procedures (MAPs).
Some of these procedures use the using system service aids that are described in
&dimbs., &dimfn..
Disk Drive Module Power-On Self-Tests (POSTs)
Attention: Disk drive modules are fragile. Handle them with care. Follow all
ESD-sensitive parts procedures when handling disk drive modules. For ESD
information, see “Handling Static–Sensitive Devices” on page 6-2.
The disk drive module POSTs start each time the module is switched on or when a
Send Diagnostic command is received from the SSA adapter. They check whether
the disk drive module is working correctly. The POSTs also help verify a repair after
a FRU has been exchanged.
There are two power-on self-tests: POST-1 and POST-2.
POST-1 runs immediately after the ‘power-on reset’ line goes inactive, and before
the disk drive module motor starts. POST-1 includes tests of the:
Microprocessor
ROM
Safety circuits
If POST-1 completes successfully, POST-2 is enabled.
If POST-1 fails, the disk drive module check light stays on, and the disk drive module
is not configured into the SSA network.
POST-2 runs after the disk drive module motor has started. POST-2 includes tests
of:
Motor control
Servo control
Read and write on the diagnostic cylinder (repeated for all heads)
Error checking and correction (ECC)
If POST-2 completes successfully, the disk drive module is ready for use by the
using system.
Appendix A. SSA Problem Determination Procedures A-1
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