[Coco] A CoCo 3 Hard Drive System

[Dave Wade]

Its my understanding , from the Wikipedea page on SASI that it is broadly
equivalent to SCSI 1. So you would need something less than 1gb, probably
with the ability to disable parity. Many years ago I used one of these
adaptors on my Atari ST. Its also possible its ROM is hard coded with the
geometry of the Miniscribe drive. The Atari had a Geometry table in a file
you could update.

Dave Wade
G4UGM



On 27 Jan 2015 06:20, "Mark J. Blair" <nf6x at nf6x.net> wrote:
>
> I just received an old hard drive system for the CoCo 3 from an eBay
purchase. I bought it purely out of curiosity, since I've never used a hard
drive with a CoCo before. I don't really have any expectation that it'll
actually work, but it should be fun to experiment with. I figured that I
might as well write a bit about it here in case it stimulates any
interesting discussion. I don't know how long it'll be before I try using
it, since I have so danged many projects, but one of these days it ought to
make for a nice blog post.
>
> The system consists of:
>
> * An external drive enclosure containing a Miniscribe 3425 20 meg 5.25"
MFM drive, a Xebec S1410 SASI to MFM controller card, and a power supply.
>
> * A hard drive interface cart. Exterior is white painted metal, with no
markings. The circuitry inside is very simple, and there's no ROM. It
connects to the drive cabinet with a 50 wire ribbon cable.
>
> * A floppy controller marked "Hard Drive Specialist Color Computer
Controller". Inside there's a 28 pin EPROM marked "OWLWARE HDBASIC3".
>
> * Some floppies and documentation.
>
> I'll be pretty surprised if that Miniscribe drive works at all. Notes
that came with the system suggest that the original owner was having
trouble with it. My very first hard drive was a Miniscribe 20 meg 3.5" SCSI
drive, part of a Supra 4x4 hard drive system for my Amiga 1000. That drive
failed in a year or two as I recall. It was such a junky drive that it used
a stepper motor for head positioning, but they didn't bother with an
optical sensor for track 0; instead, the drive just hammered the head
carriage against the stop at power-on to find track zero. Between that
experience and the old tale of Miniscribe literally shipping bricks, I have
no love for Miniscribe drives.
>
> I'm not very familiar with SASI. It's my understanding that SCSI is a
descendant from it. I wonder if some sort of modern SCSI drive emulator
like the SCSI2SD card might work with that SASI cartridge?
>
> Some of the wires inside the drive enclosure look like they've been
nibbled a bit, and something that looked like a hamster food pellet was
rattling around in the case. So, I'll want to examine it a bit more and
patch some stuff up before I apply power for a smoke test.
>
> --
> Mark J. Blair, NF6X <nf6x at nf6x.net>
> http:// <http://www.nf6x.net/>www.nf6x.net/ <http://www.nf6x.net/>
>
>
> --
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