Data Systems Design DSD-880 8" floppy and hard drive?

From: Stuart Johnson <ssj152_at_charter.net>
Date: Mon Jul 21 00:08:00 2003

----- Original Message -----
From: "Jerome H. Fine" <jhfinexgs2_at_compsys.to>
To: "Stuart Johnson" <ssj152_at_charter.net>; <cctalk_at_classiccmp.org>
Sent: Sunday, July 20, 2003 7:15 PM
Subject: Re: Data Systems Design DSD-880 8" floppy and hard drive?


> >Stuart Johnson wrote:
>
> > I had one of these boards connected to a pair of Qume (851) drives back
in
> > the early 80's. They worked GREAT, could read, write, and format RX01,
RX02,
> > and with a modified driver, did DSDD for about 1.2mb per floppy!
>
> Jerome Fine replies:
>
> Which operating system had the modified drivers? I use RT-11
> and DEC never bothered to write a driver for an RX03.
>
> > I wish I had one of these controllers now (I have a pair of 8" drives).
>
> There are controllers available for the DSD-880 which interface
> on the Qbus for both the RX03 and the 8" hard drive. Unfortunately,
> the current hardware set-up handles only ONE RX03 in addition
> to the 8" hard drive.
>
> Sincerely yours,
>
> Jerome Fine
> --
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>

Jerome,

The v4.0 distribution of RT-11 comes with source to the DY driver (RX02),
which has "commented out" code for DSDD operation, that as best as I can
remember, almost works. Until about 2 years ago I still had the floppy with
the source, but I determined that I would never need that "stuff" again
and - you guessed it - threw it away. As I recall, it was relatively easy to
make it work and it maintained compatibility with the RX01 and RX02 formats.
As I understand it, the RT-11 v5 code completely removed the DSDD code.

At the time I did this, I had been building multi-terminal RT-11 monitors,
written a driver for a BCU-11 MIL-STD 1553 controller, and installed
TSX-Plus. I was pretty "up" on programming RT-11 at that time. I had also
written a Fortran program to read a UCSD P-system disk and write selected
files to a CP/M disk, helping me to learn about sector interleave.

In case you and any other readers are wondering, yes, I have regretted
throwing away the RT-11 media distribution kit, the working floppies for
RT-11, my "enhanced" drivers and the one I wrote from scratch - about a
thousand times since I did it.

Regards,
Stuart Johnson
Received on Mon Jul 21 2003 - 00:08:00 BST