12 Jan
1999
12 Jan
'99
1:55 a.m.
While I realize that it would not have been possible to
make
their graphics part of the standard OS for a PDP-11, I
was led to believe that the PR0 350/380 had access to
their bit mapped screen displays. While doing such
manipulations was likely discouraged, is that a true
statement of the situation and in a few lines, how was
it done? I may have a working PRO 350/380 and
it would be interesting.
Yes, it is true... in fact, when the PRO was not yet real hardware,
the development group had special Qbus options for their Qbus -11
systems which were very similar to what was eventually made into
the bitmap graphics of the PRO. This way, the software could be
developed before the hardware was ready. I have one of these
proto boards. There is a minor difference between programming it
and the real PRO bitmap -- two registers are swapped...
However, user programs doing direct access is frowned upon since
the display could get really garbled if every application which
wanted to did so... So there were a set of library routines which
were supplied with RT-11 which implemented GIDIS. This is essentially
the same GIDIS which was distributed with P/OS.
Megan Gentry
Former RT-11 Developer
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