Reading ESDI disks

Nigel Johnson nw.johnson at
Thu Feb 11 11:33:50 CST 2021

I'm about to try the very same thing.

I have a MicroVAX II with a sigma MSCP ESDI controller.  It can be set
for soft-secoring or various numbers of hard sectors.  That is what I
see is the big issue with these drives.

A friend gave me two drives that had been written on a PC under *nix.

I do have some cable problems which I have to work on, but my first
power-up revealed one of the drives and said it recognised the fact that
it had 36 sectors. However when I tried to read it, it hung.  More
experimentation needed, but I am sure if the controller will read the
blocks I will be able to extract an image to send to my friend to decode :-)

let's exchange notes as we proceed.  My effort is inter-twined with
various other actoivities so I can't say when.



Amateur Radio, the origin of the open-source concept!
Skype:  TILBURY2591 nw.johnson at

On 2021-02-11 12:25 p.m., Mattis Lind via cctalk wrote:
> What is the best way of dumping the contents of an ESDI disk?
> I have an original IBM Enhanced ESDI ISA controller board. Could that be
> used under Linux? Or NetBSD/FreeNSD? I googled but didn't find much.
> Is there any other way of dumping the disk contents?
> In theory it should be just a matter of clocking the raw data and finding
> the marks and extracting the data. Has anyone done something similar?
> /Mattis

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