6.1 Diagnostics
C141-E235 6-3
The HDD does not reply to the loop for up to 2 seconds after the initial self-diagnostics is started.
After that, the HDD can accept the I/O operation request correctly, but the received command, except
the executable commands under the not ready state (such as INQUIRY, START/STOP UNIT), is
terminated with the CHECK CONDITION status (NOT READY [=2]/Logical unit is in process of
becoming ready [=04-01] or Logical unit not ready, initializing command required [=04-02]) during
the interval from the spindle motor becomes stable to the HDD becomes ready. The executable
command under the not ready state is executed in parallel with the initial self-diagnostics, or is
queued by the command queuing feature and is executed after completion of the initial self-
diagnostics. When the command that comes under the exception condition of the command queuing
is issued at that time, the HDD posts the BUSY status for the command. When the error is detected
during the initial self-diagnostics, the CHECK CONDITION status is posted for all commands that
were stacked during the initial self-diagnostics. For the command execution condition, refer to
Section 2.4 “Command Queuing Function” and Subsection 2.7.4 “Command processing in the not
ready state” of the Fibre Channel Interface Specifications.
(2) Online self-diagnostics (SEND DIAGNOSTIC command)
The initiator can make the HDD execute self-diagnostics by issuing the SEND DIAGNOSTIC
command.
The initiator specifies the execution of self-diagnostics by setting 1 for the SelfTest bit on the CDB in the
SEND DIAGNOSTIC command and specifies the test contents with the UnitOfl bit.
When the UnitOfl bit on the CDB is set to 0, the HDD executes the hardware function test only once.
When UnitOfl bit is set to 1, the HDD executes the hardware function test, seek (positioning) test,
and data write/read test for the Internal test space only once.
a. Error recovery during self-diagnostics
During the self-diagnostics specified by the SEND DIAGNOSTIC command, when the
recoverable error is detected during the seek or the write/read test, the HDD performs the error
recovery according to the MODE SELECT parameter value (read/write error recovery parameter,
additional error recovery parameter) which the initiator specifies at the time of issuing the SEND
DIAGNOSTIC command.
PER Operation of self-diagnostics
0 The self-diagnostics continues when the error is recovered. The self-
diagnostics terminates normally so far as the unrecoverable error is not
detected.
1 The self-diagnostics continues when the error is recovered. If the
unrecoverable error is not detected, the consecutive tests are executed till last
test but the self-diagnostics terminates with error. The error information
indicates that of the last recovered error.
b. Reporting result of self-diagnostics and error indication
When all specified self-diagnostics terminate normally, the HDD posts the GOOD status for the
SEND DIAGNOSTIC command.