[Coco] SCSI/SASI HD interfaces...

[David Gettle]

Owlware (LRTech) was a hybred system, neither truly SCSI or SASI The drives
were MFM. There was a board that plugged into the CoCo, then there was a
second board inside the drive case that the actual hard drives attached to
that could handle two MFM hard drives. The board that plugged into the CoCo
was made by LRTech, the one that was in the HD case was from another
manufacturer and had specific drivers for the CoCo.

I was one of the guys that had two hard drives in one of those, and
occasionally also had a Burke & Burke HD system with two drives on that
also attached to the same CoCo3, so I was an oddball that at times had 4
40MB MFM drives on a CoCo3.

On Fri, Apr 3, 2015 at 6:40 PM, Francis Swygert <farna at att.net> wrote:

> Date: Fri, 3 Apr 2015 03:03:35 -0400
> From: Bill Pierce <ooogalapasooo at aol.com>
> To: coco at maltedmedia.com
> Subject: Re: [Coco] CoCo 2 Factory Composite Video RE'd
>
> Both Kenton and LR Tech (Owl-Ware) were scsi hard drive systems and were
> regularly advertised in Rainbow.
> ============================================
> Well, maybe. I don't really know about the Kenton and LR Tech. They may
> very well be true SCSI interfaces. According to Wikipedia:
>
> "SCSI was derived from "SASI", the "Shugart Associates System Interface",
> developed circa 1978 and publicly disclosed in 1981.[2] A SASI controller
> provided a bridge between a hard disk drive's low-level interface and a
> host computer, which needed to read blocks of data. SASI controller boards
> were typically the size of a hard disk drive and were usually physically
> mounted to the drive's chassis. SASI, which was used in mini- and early
> microcomputers, defined the interface as using a 50-pin flat ribbon
> connector which was adopted as the SCSI-1 connector. SASI is a fully
> compliant subset of SCSI-1 so that many, if not all, of the then-existing
> SASI controllers were SCSI-1 compatible."
> I don't know the differences, but the Disto controllers were SASI and only
> supported two devices, IIRC. They used less than 50 pins, but I think a lot
> of the grounds were left out. IIRC SASI/SCSI used alternating grounds (25
> grounds, 25 signals). Disto may have dropped some of the signal pins as
> well. Most of the SCSI controllers for the CoCo only supported hard drives
> -- not much else was ever used on a CoCo, and it was quite the unusual CoCo
> user that had more than two HDs connected -- most only had one.
>
> Frank Swygert
> Fix-It-Frank Handyman Service
> 803-604-6548
>
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