Date : Sat, 06 Jan 2007 19:02:09 -0000
From : BBCMailingList@... (Ian Wolstenholme)
Subject: Superform Problem
Thanks for the reply. I appear to have solved the
problem now by experimenting with the interleave.
It's a Rodime RO203E Winchester, which is a 30MB
MFM disc with 640 cylinders and 6 heads according
to 2 sources I have found.
Incidentally, I'm not sure what happens if you try
to format a disc with a drive shape greater than
its true size, I've not tried it and I'm not risking it
with this one!
Sometimes the free space map ends up bigger than
the disc capacity, for instance when using the RLL
version of Superform with an MFM controller (and
presumably this also translates the defect list
incorrectly). When you try to access a sector
which doesn't exist, it results in a Volume overflow
or Illegal block error.
----- Original Message -----
From: Mike Tomlinson [mailto:mike@...]
Sent: Sat, 6 Jan 2007 14:27:55 +0000
Subject: Re: [BBC-Micro] Superform Problem
In article <78A77EEAEA2E4828B4E7B64CEE67A148.MAI@...>, Ian
Wolstenholme <BBCMailingList@...> writes
>I've got out the Acorn Winchester Disc again
>to see if I can get it formatted correctly. When it
>arrived, it was formatted as a 10MB drive but in
>reality it's a 30MB disc.
How do you know it's a 30MB disc? What make and model is it? What is
the geometry you're formatting it to? (# cyls, # heads, # spt)?
>Something seems to go wrong on the re-format
>because I can hear the disc "ticking" as if it is
>working but then it seems to re-calibrate and
>starts "ticking" again and repeats this process
>about ten times before Superform stops, giving
>Error 24 in Format, which is Bad Argument
>according to the Adaptec error list.
This is typical of the behaviour you would see if you were trying to
format a disc with a capacity that exceeded its design capacity. I
suspect the "re-calibrate" you describe is actually the heads hitting
the hard stops. What happens after that is drive-dependent. Some will
continue stepping the heads into the stops, some will recalibrate, some
may even spin down.
I can't remember how the Adaptec boards store information about the
attached drive, though the usual technique is to reduce the number of
available cylinders by one and store the controller data in the last
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