21 Oct
2008
21 Oct
'08
7:26 p.m.
Tony Duell wrote:
[Raster-scan characters on a vector display]
Keep in mind that the VT11 is a second processor which is reading
through the same main memory as the PDP-11 processor. Any vectors or
characters are refreshed with every pass through the "display file"
which is simply the list of display commands in memory. All one needs
to do to move the vectors or text is to alter the data for the beam
positioning commands, and viola, the text or vectors 'move' on the next
refresh.
Megan Gentry
Former RT-11 developer
(and developer of some programs which did simple circuit design and test
using the GT40)
The Tektronix 4052 and 4006 (and presumaby 4051
and 4012) do this.
These machines all have storage-tube vector displays, but when you want
to display text, scan a little dot matrix of the character. The 4052 at
least can put this little dot matrix at any addressable point on the
screen, not limited by the character block spacing or even (AFAIK) the
dot matrix spacing.
I believe that's true of the VT11 too. You can put a character wherever
you want it .