Re: WD1002A-HDO

From: Ethan Dicks <ethan.dicks_at_gmail.com>
Date: Tue, 23 Nov 2021 13:53:21 -0500
Message-ID: <CAALmimkQRKLxaWLn9wuh-xPndMQ3eF1ckRAMJJD2MxMCcGCKWA_at_mail.gmail.com>
On Tue, Nov 23, 2021 at 11:54 AM Roberto Muscedere <rmusced_at_uwindsor.ca> wrote:
>
> I did the VICE emulation for this drive and I did go through the disk controller code. Here is what I can decipher from my notes:

Thank you!  This is a very clear list of what's going on.

It seems the FORMAT code is the same ($04) as the OMTI 5000-series but
the ASSIGN DISK PARAMETERS code is only similar.  I didn't check the
others.

> I heard stories of a Commodore dealer in the USA which sold higher capacity disks by changing the controller ROM, but I have no verification of it.

I heard of this too but have no concrete information.

As I understand it, they put in a 20MB drive and twiddled the geometry
numbers to max out the filesystem (as you calculated, about 16MB).

> If anyone has one of these modified units, I would certainly want to take a look at it so that we can preserve the complete history of this unit.

That would be cool to see.

-ethan
Received on 2021-11-23 21:00:03

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