BIOS settings for old HD

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I need to put back a disk in a very old 286, but since I dont know the
BIOS settings it wont work.

You can select either RLL or MFM mode, and then specify a type from 1 to 47.

47 should be automatic bu this does not work, when I load DOS from a
floppy and run fdisk, the data is wrong.

Is there some list or tool to get these settings right?

It's a WD93048-A, 782 cylinders, 4 heads and 27 sectors.
The drive indicates it's a WD93044-A, but this does not match the CHS
settings, also indicated on in, so I assume its the 1s one, casue my
BIOS also says this.

Thanks in advance,


Re: BIOS settings for old HD

Wim Cossement wrote:
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    I am not sure I understand exactly what you mean, but if I recall
correctly a 286 used a setup disk for setting the drives in CMOS.  I
would assume you know this since you said you are looking at disk

    The disk choice number 47 is probably NOT automatic, but a choice where
you can specify the parameters.  Sometimes you must first choose the #47
choice and hit enter, and then it will allow you to specify the CHS by
tabbing to the different fields.

    If you did not have the choice of entering your custom parameters,then
you could do the following:

   When you install a HD in a computer using such a setup routine, you
may not find the exact parameters on the setup routine or a choice where
you can enter your own.  When this happens, the heads and sectors are
the key items.  That is, if you find a CMOS choice with the same heads
and sectors, and FEWER cylinders than those on your HD, use it.  This
may result in using less than the HDs potential capacity, but since
there is no disk number choice that has exactly the parameters you need,
that is all you can do.

    It has been a long time since I setup a 286, so I may be wrong about
how your computer sets up.

Re: BIOS settings for old HD

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I managed to get it running now, so I won't bother, I spent enought time
to get it working... :-)

But I tried everyting in the BIOS but did not find anything where I
could set the CHS.

Also, is there some list about what type (the 1-47 list) uses what CSH
specs? And the disk was not even in their discontinued products anymore,
so a setup disk would be danm near impossible.

I got my hands on a 4.01 DOS floppy, the same as it used and used that
to fdisk and format (with /s) the drive so it booted.
Then I copied all the files back that were on my Win2k machine, but left
the unchanged, and that did the trick.
The disk has however been partitioned at 63 MB or so instead of the 420
it has, but I don't mind since I come from a 40 MB disk.



Re: BIOS settings for old HD

Wim Cossement wrote:
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    If you are happy, that is all that matters.  But there was no way of
changing the parameters for type #47?  Like you suggested, normally you
can change them in that type.  In that era, everyone was doing their own
thing, so nothing would surprise me.

Re: BIOS settings for old HD

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But there was at least no obvious way of chancing type 47, entering in
the BIOS was accept and reboot.
I also had to ask a senior sysad here what the combination was to get
into it, being CTRL+ALT+ESC, and he also had a look at it but still it
was a no go...


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