Re: ProFile HD setup

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

Ernest replied (to me ">>"):

>> >You can listen to the step motor (or remove the cover and watch it). It
>> >should move with a smooth ticking sound, any irregularities indicate the
>> >use of a spare sector.
>>
>> Wow!  You mean the Profile controller does a complete surface scan
>> on each power cycle?  Amazing!  (And stupid, if it takes more than
>> thirty seconds--even more amazing if it takes less than five minutes!)
>
>The whole process only takes 30 seconds or so.

Something is fishy here.  10MB is 10,000KB, or 20,000 512-byte blocks.
How does a 1980's disk drive accesses 20,000 of _anything_ in thirty
seconds?

And what does it mean to "relocate" a bad block?  If the block is in use
and cannot be correctly read, then although the block can be re-mapped
to a spare, its content will be wrong.  This is not exactly graceful error
recovery!  Controller-driven sector sparing makes sense 1) on a blank drive,
prior to OS formatting (since data content is irrelevant), or 2) on an in-use
drive if retries (with possible threshold tweaks and/or error correction) can
recover the data intact.  In the former case, it does not make sense to do
it each power cycle, and in the latter case, it does not make sense to
_wait_ for the next power cycle.

I'm not saying it doesn't do it--stranger things have happened--but I am
saying that it doesn't make sense.

-michael

 Email:  mjmahon@aol.com
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