11 Dec
2018
11 Dec
'18
1:46 p.m.
I was doing something similar, on a PDP8/L driving a Tektronix scope with a camera
attached, using code written in Focal - University of Washington, 1972.
I learned a great deal about font generation, given that the code had to trace out each
letter shape via X, Y coordinates...
From: "cctalk" <cctalk at classiccmp.org>
To: "Toby Thain" <toby at telegraphics.com.au>
Cc: "cctalk" <cctalk at classiccmp.org>
Sent: Tuesday, December 11, 2018 1:33:52 PM
Subject: Re: BIG ol tektronix scope 555 - need it gone - make an offer
On Dec 11, 2018, at 3:30 PM, Toby Thain <toby at
telegraphics.com.au> wrote:
On 2018-12-11 9:15 AM, Paul Koning wrote:
Curious what year that was, if you don't mind disclosing?
1974, at Lawrence University which had that 11/20 (with 8 kW of memory, DECtape, RC11,
AA11, AD01, DR11, and ASR33) in the physics lab.
paul
On Dec 11, 2018, at 7:59 AM, Toby Thain via
cctalk <cctalk at classiccmp.org> wrote:
On 2018-12-11 1:17 AM, devin davison via cctalk wrote:
I made such a setup in college: we had an 11/20 with AA11 (and other lab I/O gear). I
hooked those up to the X/Y inputs of a scope, and a digital I/O line to the Z input. Then
loaded coordinate pairs into a buffer on the RC11 disk, which was set up to do DMA
directly to the AA11 data CSR. Worked nicely, and with low overhead on a machine that
certainly could not afford to do refresh in software. The line about being used with an early computer
as a display caught my
eye. How would it be used as a display, what kind of graphics capability
would it have? is there an interface for the thing for the pdp 11 or a
modcomp? Those are the old systems i have on hand that i might be able to
interface to it.
A scope is at heart an electrostatic CRT with X and Y deflection ...
For digital computers, output is point plotting, vector drawing, and/or
character generation depending on the sophistication (= cost) of the
hardware involved. You'd also need to find or write suitable software :)
Yes, there were interface cards for PDP-11, such as AA11 (dual DACs).