21 Jun
2006
21 Jun
'06
11:26 p.m.
Hmm... reminds me of a board I have for the PDP-11
(but with one
channel)... it was never directly supported by any PDP-11 OS I know of
(i.e. - no graphical login), but it was easy to talk to from an RT-11
program and scribble pretty pictures on. We used to use only the
green channel and display 512x512 mono images on it.
There were some quite interesting graphics display systems for the
PDP11/VAX. Even though I don't have a graphical display on this PC, I
have collected a number of display systems for the PDP11, including :
DEC VT11 / GT40 (Vector display that DMA's data from main memory via the
Unibus)
Ramtek 9460. Alas mine is incomplete (just the cardcage and boards), but
it seems to be a 68000-based unit
Grinnel framestore. This seems to be a digitiser as well (there's what
looks like an ADC on one of the boards), and is mostly hand-wired, not
PCB. The Unibus interface is a DR11-B. I know noting about this unit
PPL video disk. This uses a head-per-track hard disk to record the video
(it rotates at the frame rate, the analoge video signals are FM modulated
and recorded on the disk).
I2S Model 70 and Model 75 Image processor/display systems. I think I've
described these before. They yse semiconductor RAM (the earliest ones I
haev contains over 3000 4K bit DEAM chips...), organised as byteplanes
(512*512*8 bits IIRC). The byteplanes feed programmable lookup tables,
then outputs of those are added, go to more lookup tables, then to the
DACs. Oh yes, there's also the feedback ALU (planes 0 and 1 are taken as
a 16 bit accumulator plane, you can combine that with any other plane and
write the result back to the accumulator), a histogram board, cursor,
text overlay, etc Fortunately I have the manuals....
-tony