Date   : Sun, 21 Dec 1997 14:59:03 GMT+2
From   : "Mnr WE Meyer (NW5-44) x2637 (Walter)" <wmeyer@...>
Subject: Re: Hard Drives

Previously Crispin Boylan <viewtronix@...> wrote:
> I've just been looking at the old messages to the mailing list, the ones
> from about 1992 or thereabouts, and I have been reading a lot of message
s
> about someone who produced an SCSI controller board for the BBC, so that
> any SCSI device could be connected, the total cost then was about £35,
 so
> it should have fallen a bit by now.

About a year ago I modified an old "SCSI" interface card 
(manufactured by GSL - Geophysical Systems) to work with a more 
modern SCSI hard disk drive, after the old Adaptec interface and 
Seagate MFM drive combination broke.  The set-up is currently used in 
an E-NET fileserver for 20 BBCs in the "computer games room" of a 
local high school.  A year later it still runs happily without any 
maintenance.

IIRC, the modification involved cutting one track an soldering a new
link, and a minor software modification, something like changing
LDA#0 to LDA#1.  

In tried to find a more general "hardware-only" solution, without 
success.

I have kept some notes, so if anybody has an old GSL host adaptor
card they want to fix up...  If you are adventurous, you could build
the whole SCSI interface from scratch.  I have roughly traced the 
circuit - it uses about 10 generally available ICs, and it 
isn't that complicated at all.

Good luck!

Walter

--
Walter Meyer (wmeyer@...              )
Department of Physics, University of Pretoria, South Africa