18 Dec
2015
18 Dec
'15
8:19 a.m.
On Thu, Dec 17, 2015 at 8:53 AM, Mike Boyle <tulsamike3434 at gmail.com> wrote:
--
I did a Google search on a straight eight system and found this . .
http://www.pdp8.net/shows/vcfe12/exhibit_small.jpg
If this is the correct image I see a small round screen and if memory
serves me a line
like a heart beat monitor. Fi I am correct how in the world would you read
this.
One option on an 8 is a scope interface. It has a 10 bit X DAC, a 10 bit Y
DAC and a Z driver, The 8 I have has this option but when they sold the 8
they didn't sell the storage tube scope with it. Around 1975 or 1976 I
wrote a line printer driver for the scope for OS/8. The dot matrix was
stored in 128 words and supported 64 character ASCII (a 4x6 dot matrix took
2 words per character). So on that little display were 204 characters on a
line and 146 lines for the initial implementation. Too hard to read even
for 20 year old eyes. I think I made it do half that in each axis so
102x73. Still small but very fast. I used this for debugging programs.
After all the ASR 35 teletype was only10 cps. I have not found a copy of
this driver in my stuff yet. I am hoping it is not one of those things
that was lost forever. And even if I had it I don't have the storage scope
so it is not usable.
I recently bought a period correct scope for the 8 and one of these days I
will get around to fixing it and hooking it up. Not a storage tube but the
correct device for playing spacewars.
--
Doug Ingraham
PDP-8 SN 1175
