Specifications
Appendix E. 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 system service aids that are described in
Diagnostic
Information for Multiple Bus Systems
, order number SA23-2769.
Disk Drive Module Power-On Self-Tests (POSTs)
Attention: Disk drive modules are fragile and must be handled with care. Follow all
ESD-sensitive parts procedures when handling disk drive modules. For ESD
information, see “Handling Static-Sensitive Devices” on page 300.
The disk drive module POSTs start each time the module is turned on or when a Send
Diagnostic command is received from the SSA adapter. The POSTs verify that 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.
v POST-1 runs immediately after the ‘power-on reset’ line goes inactive, and before the
disk drive module motor starts. The following are tested by POST-1:
– 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.
v POST-2 runs after the disk drive module motor has started. The following are tested
by POST-2:
– 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.
Adapter Power-On Self-Tests (POSTs)
Power-on self-tests (POSTs) reside in the SSA adapter. These tests ensure that the
adapter does not run the functional code until the hardware that uses the code has
been tested. The hardware consists of only the adapter card and any memory DIMMs
and fast-write cache modules that are attached to the adapter. Some POST failures
cause the adapter to become unavailable to the system. Other POST failures allow the
adapter to be available, although some function may not be enabled. The particular
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