Technical information

HGST Ultrastar C15K600 Hard Disk Drive Specification
317
20.12
Diagnostics
The drive will execute Power on Diagnostics at power on time to assure the correct operation of the drive by
validating components (ROM, RAM, Sector Buffer, EEPROM, HDC, Spindle Motor, Actuator), checking stored
information in the Reserved Area and EEPROM, and verifying fault detects circuits.
Self-test can be invoked by issuing a SEND DIAGNOSTIC command.
20.12.1
Power on Diagnostics
At power on time the following tests are executed:
1. Validation of ROM and EEPROM
2. RAM test for internal RAM
3. Test and Initialize HDC registers
4. RAM test for Sector Buffer
5. Start Spindle Motor (if enabled)
6. Calibration of Actuator
7. Read/Write test for all Heads
8. Validation of RAM code and data table (RDM, Log, Mode Page) from the Reserved Area
If Auto spin up is disabled, steps 5 - 8 will be executed by the first START STOP UNIT command which has the Start
bit set.
Faults detected before successful completion of the HDC section could prevent the drive from responding to a
selection.
Faults detected after the successful completion of the HDC test section will be reported as CHECK CONDITION
status to the Initiator on the first command issued after a fault is detected (except for the INQUIRY, REPORT LUNS
and REQUEST SENSE commands). The INQUIRY, REPORT LUNS and REQUEST SENSE commands will always
be responded with a GOOD status. Detecting a fault during power on will not terminate execution of the tests nor will
it terminate the power on process.
20.12.2
Self-test via SEND DIAGNOSTIC Command
20.12.2.1
Default Self-test
The default self-test is invoked by the SlfTst bit in the SEND DIAGNOSTIC command. The response is simply a
GOOD status if the test is successful or a CHECK CONDITION status if the test fails.
The following tests are performed by the default self-test (in the order defined):
1. Spin check is to check if the spindle motor is running at the correct speed.
2. Write, Read and Compare test is a disk read/write test. It writes data to a predefined location in the
reserved area and then reads it back and validates the content. All heads are tested.
3. Seek test is a servo test. It validates seeks to 256 random locations out of the full volume.
20.12.2.2
Short and Extended Self-tests
There are two other types of self-tests that may be invoked using the Function Code field in the SEND DIAGNOSTIC
command: a short self-test and an extended self-test. The tests performed in the short and extended self-tests are
described later. The time required by a logical unit to complete its extended self- test is specified in the Extended
self-test Completion Time field in the Control Mode Page. The results of self-test can be retrieved via the LOG
SENSE command for Log Page 10.