MFM/RLL data recovery

[Tom Peters]

At 05:18 PM 4/4/2005 -0500, you wrote:
>From: "Ryan Underwood" <nemesis-lists at icequake.net>
>Sent: Monday, April 04, 2005 4:21 PM
>
>
>>
>>OK, I posted about this a few weeks ago and now I have some more
>>information.
>>
>>The drives in question are a ST-225 20MB (615/4/17) that came out of an
>>XT (so would have been using a 8-bit controller) and a ST-238R 30MB
>>(615/4/26) of unknown origin.
>>
>>I don't have or even know what the original controllers were, the
>>machines were gutted/given away years ago by the owners.
>>
>>I have a 386 testbed which I'm using, and plan to laplink the files over
>>to another machine once they are accessible.
>>
>>The only card in the 386 is a VGA card.  Turbo is off.
>>
>>I have the following controllers:
>>- WD1002A-27X 8-bit RLL
>>- Adaptec ACB-2370A S2 16-bit RLL/floppy
>>- WD1002SV-SR2 16-bit RLL/floppy
>>- Everex EV-346 16-bit MFM/floppy
>>
>>I also have two Miniscribe 8438 30MB RLL drives.  However, they were
>>used with the 27X, which means the geometry is ambiguous depending on
>>how the jumpers were set when it was formatted.
><snip>
>
>If you are trying to recover files you are probably wasting your time, the 
>XT controllers used unique formatting and you will never read the data off 
>of the drives without using controllers indentical with ones used 
>originally.  It is not good enough to use the same brand or even chipset.

I have been able to read many old MFM drives and the occasional RLL drive. 
When the original controller was jumpered to lie about head or cylinder 
count or other facts of drive geometry, I have be largely unable to read 
those. This was several years ago.



>Randy
>www.s100-manuals.com


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