6.1 Diagnostics
(2)Online self-diagnostics (SEND DIAGNOSTIC command)
The initiator can make the HDDs 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 HDDs execute the hardware function test only once. When UnitOfl bit is set to 1, the HDDs execute 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 HDDs perform 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 |
0The self-diagnostics continues when the error is recovered. The self- diagnostics terminates normally so far as the unrecoverable error is not detected.
1The 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 HDDs post the GOOD status for the SEND DIAGNOSTIC command.
When an error is detected in the self-diagnostics, the HDDs terminate the SEND DIAGNOSTIC command with the CHECK CONDITION status.
When the CHECK CONDITION status is posted, sense data contains detailed information on the error detected by the initial self-diagnostics.
The HDD status after the CHECK CONDITION status is posted differs according to the type of the detected error.
a)When an error is detected in the seek or write/read test, the subsequent command can be accepted correctly. When the command other than the REQUEST SENSE is issued from the same initiator, the error information (sense data) is cleared.
