FW: 77/68

From: Peter Matthewson <peter.matthewson_at_tiscali.co.uk>
Date: Wed Jan 14 15:32:14 2004

 
 
-----Original Message-----
From: Peter Matthewson [mailto:peter.matthewson_at_tiscali.co.uk]
Sent: 14 January 2004 21:27
To: 'andyh_at_andyh-rayleigh.freeserve.co.uk'
Subject: 77/68
 
Andy,
 
Just saw your note on 77/68 from the classic computing mailing list.
This made me smile; I can only see about 2 references to it that I can
find anywhere on the web.
 
My acquaintance with the 77/68 began when it featured in volume 1
edition 1 of Personal Computer World that I chanced upon in WH Smith in
Dewsbury, I think this was round about December 1977. I am not entirely
sure it was the UKs first home PC because I recall reading about a 4040
based system described in Wireless World which must have been a year or
so earlier.
 
I was so captivated by all this I withdrew all my savings bought the
bits and built one, for ?60. The 6800 microprocessor cost ?14 I recall.
I managed to get it working, I am not quite sure since I was a 15 year
old schoolkid with only a multimeter for test equipment, working in
isolation and did not really know what it was that I was building. The
main problem I had was with wiring the edge connector, the data bus was
in one bit order on the edge connector and the address bus in the
reverse bit order, a detail I didn?t understand the significance of
initially. It was about 2 years before I met anyone who had any idea
what I was talking about.
 
I extended the system with 1024 bytes of ram, built a keyboard and
cannibalised an old calculator display for peripherals. And I built a 32
bits per second tone burst modem for storage of programmes on cassette
tapes. The monitor program I wrote to drive all this took 256 bytes of
memory. Those were the days - he said wistfully.
 
Its still up in the loft. I almost feel inspired to get it out and fire
it up again!
 
Regards
 
Peter Matthewson
 
Received on Wed Jan 14 2004 - 15:32:14 GMT