[Coco] A CoCo 3 Hard Drive System

[Didier Derny]

beware with SASI / SCSI. the cables are slightly different

for example the SCSI 5v termpower is on pin often connected to SASI GND

the main symptom is a the 50 wire cable burning...

if you are lucky, the controller has a fuse and you have just blown the fuse


I know that the guy working on SCSI2SD has improved his hardware to 
support old SCSI drives
I'm not sure that it fully works works with SASI






On 27/01/2015 09:47, Dave Wade wrote:
> 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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