On 2012-Apr-17 17:25:36 +1000, Jim Klimov <jimkli...@cos.ru> wrote:
>For the sake of archives, can you please post a common troubleshooting
>techinque which users can try at home to see if their disks honour the
>request or not? ;) I guess it would involve random-write bandwidths in
>two cases?

1) Issue "disable write cache" command to drive
2) Write several MB of data to drive
3) As soon as drive acknowledges completion, remove power to drive (this
   will require a electronic switch in the drive's power lead)
4) Wait until drive spins down.
5) Power up drive and wait until ready
6) Verify data written in (2) can be read.
7) Argue with drive vendor that drive doesn't meet specifications :-)

A similar approach can also be used to verify that NCQ & cache flush
commands actually work.

Peter Jeremy

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