Drive in 3B1?

Kevin O'Gorman kevin at kosman.UUCP
Sat Nov 12 02:26:54 AEST 1988


In article <1015 at naucse.UUCP> sbw at naucse.UUCP (Steve Wampler) writes:
>I have a (he thinks) fairly simple question about replacing
>the drive in a 3B1.  I see that Miniscribe has a drive, the
>model 6128, that is ST506/412, 110.1MB(formatted), with 1024
>cylinders and 8 heads.  Can I drop one of these straight into
>my 3B1 (which currently has a 40MB drive)?
> ...
>  Any comments?

Hmmmm.  The standard "67MB" UNIX PC drive has 1024 cylinders, and 8 heads.
It is actually a 71.3 MB drive, but after allowing for alternate sectors
there are 67 MB available.  How does the 6128 get 110.1 MB???  If it had
25 sectors per track it would be smaller than that; if it had 26 sectors
it would be larger.  I could probably work it out, but the idea is clear:
any drive with more than 67 MB available has more than 17 sectors, or
requires a hardware modification to the UNIX PC.

I don't know if the drivers can deal with more than 17 sectors per track.
Just about all drives I have seen stick to exactly this number.



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