I got an Apple ProFile hard drive.

From: jpero_at_cgo.wave.ca <(jpero_at_cgo.wave.ca)>
Date: Mon Feb 16 18:14:26 1998

> <Remember, all older MFM, ESDI and some early SCSI drives always need
> <annual or bi yearly LLF job.
> I have a st506 that I formatted once and never again and it still works
> fine. I do however run a program that checks it for bad sectors, haven't
> found many over the years. The need for reformats is urban legend and I
> have a bunch of RD52/53/54(mfm) and a potload of st506 and st412 drives
> that haven't been reformatted unless moved to a different system where
> the controller was incompatable with the former format.
> However to qualify that I've seen many systems with power down problems
> where they would write garbage to the disk causeing a need for reformats.
> I've also seen system with power and heat problems. Optimally the drive
> should run over a narrow temperature range that is centered at the
> temperature they were formatted at. most time they are asked to run
> much hotter and that means the stepper is not centered on the thermally
> repostioned tracks. This can be made worse by reformatting the drive
> as cold as it will warm up and all the track centering will be off leading
> to errors and a likely reformat.

Asolutely correct, and you're not there to control the temperatures
are you? So, that changes all the time, hd runs hot, all of kinds in
the field not under lab/glass room conditions. That is why they
required LLF so often. This data splatting at power cycles could be
low quality controllers and bad wiring routing near powerful current
carrying wirings. I have not seen like that except for few hard
drives that is going bad by crashing, damaging the track under it at
spin up or down. Remember, the hard drive designers did their
damnest BEST to prevent that within those hard drive itself but no
control over what is happening outside that drive itself through the
connections unless that circuit is broken which would show up as dead
hard drive.

> Later voicecoil and other servo positioned drives are immune to this as
> the servo track or embedded servo information will insure it tracks with
> temperature and bearing wear.

Thankfully, today we have all voice coil hard drives so no need for

> Allison

Jason D.
email: jpero_at_cgo.wave.ca
Pero, Jason D.
Received on Mon Feb 16 1998 - 18:14:26 GMT

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