Seagate ST336918N ユーザーズマニュアル

There are two test coverage options implemented in DST:

1.

extended test

2.

short test

The most thorough option is the extended test that performs various tests on the drive and scans every logical
block address (LBA) of the drive. The short test is time-restricted and limited in length—it does not scan the
entire media surface, but does some fundamental tests and scans portions of the media. 

If DST encounters an error during either of these tests, it reports a fault condition. If the drive fails the test,
remove it from service and return it to Seagate for service.

The drive will present a “diagnostic failed” condition through the self-tests results value of the diagnostic log
page if a functional failure is encountered during DST. The channel and servo parameters are not modified to
test the drive more stringently, and the number of retries are not reduced. All retries and recovery processes
are enabled during the test. If data is recoverable, no failure condition will be reported regardless of the number
of retries required to recover the data.

The following conditions are considered DST failure conditions:

• Seek error after retries are exhausted
• Track-follow error after retries are exhausted
• Read error after retries are exhausted
• Write error after retries are exhausted

Recovered errors will not be reported as diagnostic failures.

This section provides all of the information necessary to implement the DST function on this drive.

The drive must be in a ready state before issuing the Send Diagnostic command. There are multiple reasons
why a drive may not be ready, some of which are valid conditions, and not errors. For example, a drive may be
in process of doing a format, or another DST. It is the responsibility of the host application to determine the “not
ready” cause.

While not technically part of DST, a Not Ready condition also qualifies the drive to be returned to Seagate as a
failed drive.

A Drive Not Ready condition is reported by the drive under the following conditions:

• Motor will not spin
• Motor will not lock to speed
• Servo will not lock on track
• Drive cannot read configuration tables from the disc

In these conditions, the drive responds to a Test Unit Ready command with an 02/04/00 or 02/04/03 code.

To invoke DST, submit the Send Diagnostic command with the appropriate Function Code (001b for the short
test or 010b for the extended test) in bytes 1, bits 5, 6, and 7. Refer to the 

SCSI Interface Product Manual, part

number 75789509, for additional information about invoking DST.

The short and extended test options are described in the following two subsections.

Each test consists of three segments: an electrical test segment, a servo test segment, and a read/verify scan
segment.