ISC 3.2/harddisk & floppy problems

[Uwe Doering]

rcbarn at rwc.urc.tue.nl (Raymond Nijssen) writes:

>Here we go again:
>
>The second problem, the one with the HD controller locking up under ISC
>is known to occur in combination with Western Digital's WD1006Vsr2 RLL
>controller; it contains a bug which only occurs if 2 drives are
>attached to it and if the HD device driver has the 'overlapped-seeks' 
>feature enabled, like the one in ISC/ix has by default. It does not
>happen with ESDI.

Not so fast, please. That CCAP_NOSEEK fix may be a cure for some problems
people have with ISC's HD driver, but not for all.

I had problems for months with the following HD/controller combination:

Adaptec 2322D ESDI controller
Fujitsu 2249E ESDI HD drive (320 MB formatted)

I had two of those drives. My news partition was on the second one.
Every one or two days the second disk wasn't readable any more. That
is, it was still accessible by the controller and was at least seeking
and recalibrating while the HD driver tried to read a sector. But
no sector on the whole HD was readable/writable any more. Note that
the UNIX kernel wasn't hung or the like. It only couldn't read or write
the second drive, but was otherwise healthy. After shutting down UNIX,
the computer had to get a hardware reset. A soft boot wasn't enough to
cure this problem.

In those months where I tried to fix this problem I swapped anything.
I changed the second HD drive to another model (Fujitsu 2263E, 620 MB).
Same problem. I then used two controllers, one for every HD drive.
Didn't help. I got a new cable set. I even exchanged the power supply
and for some time had each HD drive on its own power supply. Nothing
helped. The only thing I didn't replace was the main board. But how
could a main board decide that it only wants to disable the second
HD drive. Remember, the problem was the same with both drives on
the same controller _and_ with each drive on its own controller.
And of course I tried the CCAP_NOSEEK trick. But it didn't help
either.

So what's left? It can't be an incompatibility between the Adaptec
controller and the Fujitsu HD drives, because the first drive was
the same model as (originally) was the second drive, but this
malfunction never happend with the first drive. After experiencing
all that, I don't have any other choice but to suspect that this
is a bug in ISC's HD driver.

I recently switched to SCSI HD drives, and the problem was gone,
as was to be expected.

     Uwe
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Uwe Doering  |  INET : gemini at geminix.in-berlin.de
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