27 May
2014
27 May
'14
2:47 p.m.
On Tue, May 27, 2014 at 2:02 PM, Richard <legalize at xmission.com> wrote:
In article <5384E178.9020408 at sydex.com>,
Chuck Guzis <cclist at sydex.com> writes:
<snip>
On 05/27/2014 10:08 AM, Richard wrote:
It's a vector display, just without arbitrary
graphics.
A point of curiosity--who had the first *buffered* graphics display?
That is, where the display contents were continuously refreshed from a
memory buffer. In the old days, you pretty much had to continuously
redraw a display, unless you were using something like a storage tube.
The more complex the display, the more flicker involved.
Early GPUs were basically a dedicated CPU to refreshing the display.
Examples are the GT40, where the GPU controller is an 11/05, or
something like the Megatek 6014 where the GPU controller is a Data
General Nova 3.
<http://en.wikipedia.org/wiki/DEC_GT40>
<http://terminals.classiccmp.org/wiki/index.php/Megatek_Megraphic_6014>
Interestingly enough the GT40 has the 11/05 to handle the management of
the display list and handle communications processing and the VT11 board
set handles refresh of the display from the display list. You could stick
a VT11 board set in any UNIBUS PDP-11 and have it manage the display by
refreshing from the display list memory. A GT40 offloads display list
refresh from the main CPU bus and offloads the main CPU from handling
communication to/from the graphics display.
The Imlac PDS-1 (late '69, early 1970) (and later models) also fall into
the GPU model, each PDS-1 contained both a general purpose 16-bit processor
(similar to the PDP-8 only 16 bits wide) and a Display Processor, dedicated
to processing a display program (slightly more advanced than a display list
but not much). They both shared the same memory, so a very complicated
display slowed the main processor quite significantly :).
- Josh
Some points on a timeline:
1958 SAGE display system [4]
1969 Evans & Sutherland LDS-1 [1]
1973 DEC VT11 [2]
1977 HP 1350A Graphics Translator [3]
[1] <http://en.wikipedia.org/wiki/LDS-1_(Line_Drawing_System-1)>
[2] <http://manx.classiccmp.org/search.php?cp=1&q=VT11>
[3] <http://www.hpmuseum.net/display_item.php?hw=169>
[4] <
http://bitsavers.trailing-edge.com/pdf/ibm/sage/3-62-0_Display_System_Vol1_…
--
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