Hitachi HUS154530VLF400 User Manual

Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification

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A miscompare can occur on a Verify (2F) command or a Write and Verify (2E) with the byte check (BytChk) bit active. Recov-
ery for a miscompare error is different for the two commands.

The initiator should do the following:

1.   Verify that the data sent to the drive is the correct data for the byte-by-byte compare.

2.   Read the data from the media with a Read (08) or Read (28) command and verify that the data from the media is the 

expected data for the byte-by-byte compare.

-  If all data are correct, this is an indication that the data may have been read from the media incorrectly without an 

error detected. Service the drive using the procedure specified in Section 21.21.1, “Drive Service Strategy” on 
page 339.

-  If all data are not correct, this is an indication that the data on the media is not the data the initiator expected. 

Rewrite the correct data to the media.

The drive uses the same data in the data buffer to write then read and compare. A miscompare error on the Write and Verify 
(2E) command is an indication that the drive cannot reliably write or read the media. Service the drive using the procedures 
specified in Section 21.21.1, “Drive Service Strategy” on page 339.

The microcode from the interface is validated before the device operates using that microcode. When the validation detects 
incorrect or incomplete data, the Drive enters degraded mode.

If the initiator attempted to load microcode using the Write Buffer (3B) retry the Write Buffer (3B). If the command completes 
with

•

Good Status - return to normal processing

•

Check Condition Status - service the drive using the service guidelines recommended in Section 21.21.1, “Drive Ser-

vice Strategy” on page 339.

If the check sum error occurred during normal processing, the initiator may attempt to load microcode before deciding to ser-
vice the drive using the service guidelines recommended in Section 21.21.1, “Drive Service Strategy” on page 339.

To load new microcode, the initiator should issue a Write Buffer (3B) command with the download and save option. If the 
Write Buffer (3B) command completes with

•

Good Status, return to normal processing. Retry the failing command. If the task complete with

-  Good Status - Continue normal processing.

-  Check Condition Status for check sum error - Service the drive using the service guidelines recommended in Sec-

tion 21.21.1, “Drive Service Strategy” on page 339.

-  Check Condition Status for any other error - follow the recommended recovery procedure for the error reported.

•

Check Condition Status for Check sum error, service the drive using the service guidelines recommended in Section 

•

Check Condition Status for any other error, follow the recommendations for the returned sense data.