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Diagnostics and Maintenance
6-2 C141-E219
Brief test contents of self-diagnostics are as follows.
a. Hardware function test
This test checks the basic operation of the controller section, and contains following test.
• RAM (microcode is stored)
• Peripheral circuits of microprocessor (MPU)
• Memory (RAM)
• Data buffer
b. Seek test
This test checks the positioning operation of the disk drive using several seek modes (2 points
seek, 1 position sequential seek, etc.). The positioning operation is regarded as success when the
seek operation to the target cylinder is completed.
c. Write/read test
This test checks the write/read function by using the Internal test space of the disk drive.
(1) Initial self-diagnostics
When the HDD is turned on, it runs the initial self-diagnostics. The initial self-diagnostics test the
basic operations of hardware functions.
If the initial self-diagnostics detect an error, the LED on the drive blinks. The HDD in this state
posts the CHECK CONDITION status to all I/O operation requests except the REQUEST SENSE
command. The initiator can collect sense data when the CHECK CONDITION status is posted.
Sense data contains detailed information on the error detected by the initial self-diagnostics.
When sense data has been collected after the CHECK CONDITION status has been posted, the
CHECK CONDITION status continues and the LED keeps blinking. This status can be cleared only
when the HDD is turned off and turned on again. When the status is cleared, the HDD runs the initial
self-diagnostics again.
The HDD does not reply to requests from the host system for a maximum of 2 seconds after the start
of the initial self-diagnostics. Thereafter, the HDD can accept I/O operation requests normally, but
any received command, except commands that are executable even in the not ready state, is
terminated with the CHECK CONDITION status until the spindle motor reaches the normal
rotational speed and the HDD becomes ready. The commands that are executable even in the not
ready state are executed in parallel with the initial self-diagnostics, or they are queued by the
command queuing feature and executed when the initial self-diagnostics is completed.
If the initial self-diagnostics detect an error, the CHECK CONDITION status is posted for all of the
commands received and queued during the initial self-diagnostics.