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5.3.6
Drive Self Test (DST)
Drive Self Test (DST) is a technology designed to recognize drive fault conditions that qualify the drive as a failed unit. DST validates the
functionality of the drive at a system level.
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 contents, but does some fundamental tests
and scans portions of the media.
If DST encounters an error during either of these tests, it reports a "diagnostic failed" condition. If the drive fails the test, remove it from
service and return it to Seagate for service.
5.3.6.1
DST failure definition
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 drive parameters are not modified to test the drive more stringently, and the recovery capabilities 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 recovery processes required to recover the data.
The following conditions are considered DST failure conditions:
• Read error after recovery attempts are exhausted
• Write error after recovery attempts are exhausted
Recovered errors will not be reported as diagnostic failures.
5.3.6.2
Implementation
This section provides all of the information necessary to implement the DST function on this drive.
5.3.6.2.1
State of the drive prior to testing
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 UNIT, or another
DST. It is the responsibility of the host application to determine the “not ready” cause.
5.3.6.2.2
Invoking DST
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.
5.3.6.2.3
Short and extended tests
DST has two testing options:
1.
short
2.
extended
These testing options are described in the following two subsections.
Each test consists of two segments: an electrical test segment and a read/verify scan segment.
Short test (Function Code: 001b)
The purpose of the short test is to provide a time-limited test that tests as much of the drive as possible within 120 seconds. The short test
does not scan the entire media contents, but does some fundamental tests and scans portions of the media. A complete read/verify scan is
not performed and only factual failures will report a "diagnostic failed" condition. This option provides a quick confidence test of the drive.
Table 8 Temperature Log Page (0Dh)
Parameter Code
Description
800/400/200/100GB
0000h
Primary Temperature
Drive Temperature
0001h
Reference Temperature
Default Setting
65
°
C
Changeable Range
0 to 65
°
C
