Toshiba 4006GAH Computer Drive User Manual


 
360050398
Toshiba Corporation Digital Media Network Company
Page 118 of 157
© 2005, Copyright TOSHIBA Corporation All Rights Reserved
10.8.42.6.4.2 Self-test log descriptor entry
This log is viewed as a circular buffer. The first entry will begin at byte 2, the second entry will begin at byte 26,
and so on until the twenty-second entry, that will replace the first entry. Then, the twenty-third entry will replace
the second entry, and so on. If fewer than 21 self-tests have been performed by the device, the unused
descriptor entries will be filled with zeroes.
The content of the self-test descriptor entry is shown in the following Table.
Self-test log descriptor entry
Byte Descriptions
n Content of the Sector Number
n+1 Content of the self-test execution status
n+2 Life timestamp (least significant byte).
n+3 Life timestamp (most significant byte).
n+4 Content of the self-test failure checkpoint
n+5 Failing LBA(least significant byte).
n+6 Failing LBA(next least significant byte).
n+7 Failing LBA(next most significant byte).
n+8 Failing LBA(most significant byte).
n+9 - n+23 Vendor specific.
Content of the Sector Number register will be the content of the Sector Number register when the nth self-test
subcommand was issued.
Content of the self-test execution status byte will be the content of the self-test execution status byte when the
nth self-test was completed
Life timestamp will contain the power-on lifetime of the device in hours when the nth self-test subcommand was
completed.
Content of the self-test failure checkpoint byte will be the content of the self-test failure checkpoint byte when the
nth self-test was completed.
The failing LBA will be the LBA of the uncorrectable sector that caused the test to fail. If the device
encountered more than one uncorrectable sector during the test, this field will indicate the LBA of the
first uncorrectable sector encountered. If the test passed or the test failed for some reason other than an
uncorrectable sector, the value of this field is undefined.
10.8.42.6.4.3 Self-test index
The self-test index will point to the most recent entry. Initially, when the log is empty, the index will be set
to zero. It will be set to one when the first entry is made, two for the second entry, etc., until the 22nd
entry, when the index will be reset to one.
10.8.42.6.4.4 Data structure checksum
The data structure checksum is the two's complement of the sum of the first 511 bytes in the data
structure. Each byte will be added with unsigned arithmetic, and overflow will be ignored. The sum of all
512 bytes is zero when the checksum is correct. The checksum is placed in byte 511.