Re: disk verify utility

[mjmahon@aol.com (Michael J. Mahon)]

Chris cmerrill wrote:

>I need to verify that a disk drive is functioning properly -
>basically that it can read/write all sectors reliably.
>
>I see a lot of possibilities on Asimov (for instance, the
>DataLife Disk Drive Analyzer)...any recommendations
>on which is the most thorough and/or easiest to use??

If a drive can correctly read/write any sector near track 0
and track 34, then many drive-related issues are ruled out.

A dirty head is a very common cause of read/write errors.
Head alignment is another.  Wrong rotational speed is
also quite common.  A speed check and adjustment is
included in mostl copy programs.

The DDA is a good program, but a copy of the disk is not
an original, and the original contained some non-standard
tracks which even a good copy program can't duplicate
(primarily in their off-center, track-crowding characteristics).

Assuming that you have a correctly aligned drive to write
a copy on, however, DDA does have tests that can be
useful in diagnosing a drive.

For most purposes, comparing a known-good drive to a
suspect one by verifying that disks formatted on one can
be read/written correctly by the other is good enough.

-michael

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