19 Jun
2007
19 Jun
'07
7:33 a.m.
On 6/19/07, Robert Borsuk <rborsuk at colourfull.com> wrote:
I've been loosely following this thread and never
heard of a T11 from
DEC. So good'ole Google and Bitsavers saves the day, but it get's
me thinking. Has anybody done any design's with this processor?
Yes (see the thread where it appears in a few video games). DEC used
it as a PDP-11-instruction-set-compatible microcontroller. It appears
on a few peripheral boards (the RQDX3 comes to mind), and a few other
places.
For some real boots-on-the-ground history, we turn to Bob Supnik...
http://simh.trailing-edge.com/semi/t11.html
(I did not know about his T-11-based RT-11 box - I should ask him about it).
Why wasn't this processor used instead of the
6100?
In what? In video games? the 6100 _might_ have been a competetive
architecture when it was new in the mid-to-late 1970s, but as
competition against an early 8-bit micro, not a 16-bit micro, which
the T-11 is. From looking at the Atari line at the time, it seems
that they were positioning the T-11 against the Motorola 68000.
Presumably there was some engineering or marketing or production
reason to go with the T-11 over the 68000, but, as much as I like the
PDP-11, I can't imagine what that would be. Perhaps the $10/unit cost
that Bob Supnik cites was favorable compared to, say, trying to go
over 8MHz on a 68000, but that's mere speculation. I know that at the
low-point in the 68000 timeline, it was going for about $3 each in
reasonable quantities, but I don't know where that curve compares to
the $10 each for the T-11.
I'm not saying you _couldn't_ make a video game based on the IM6100,
but it didn't happen to have been done, and would probably just end up
as a demonstration of engineering prowess, not something that would
have made sense from a business standpoint in 1976.
-ethan