Re: 8250 disk drive "exerciser"

From: Bill Degnan <billdegnan_at_gmail.com>
Date: Fri, 23 Dec 2022 13:48:17 -0500
Message-ID: <CABGJBud4+6qGtciCUbiq-xVG6kr1z9Z6wFCL3fkPF9Mhbd==_w_at_mail.gmail.com>
I have this, if it helps, but it's probably compiled:
https://vintagecomputer.net/commodore/IEEE_drives/sfd-1001%20test.PRG

You might also want to check SFD-1001 utils. as it's more or less the
single drive version of the 8250
Bill

On Fri, Dec 23, 2022 at 1:16 PM Francesco Messineo <
francesco.messineo_at_gmail.com> wrote:

> Hi all,
> I need to diagnose a faulty 8250 disk drive (actually a LP one). Years
> ago I found a nice program that works with a 1541 that allows turning
> on/off the spindle motor, seek to track 1 (i.e. bump the head to the
> stop), seek 1 or 1/2 track in and out. This is very handy to observe
> the analog signal path issues. Now I understand that this can be
> easily done on a 1541 since the same CPU is controlling the
> interface/DOS and the actual stepper/spindle outputs.
> Now, the 8250 obviously has two CPUs and the spindle/stepper one only
> executes so called "jobs" posted from the other CPU. I can see
> there're seek/read/write jobs but it seems to me that all will look
> for an actual sector header and throw back an error if that can't be
> found correctly.
> Before I dig deeply into the ASM code of the 8250's DOS, can anyone
> point me in the right direction to write such a tool (start, stop,
> step in/out) for dual CPU drives? Maybe a modified format track
> without switching to write mode? My other option would be writing a
> custom ROM for the 6530 code (that's already on a separate eprom on
> the LP, so nothing *too* hard to do).
> Thanks in advance.
> Frank IZ8DWF
>
>
Received on 2022-12-23 20:02:40

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