Allison J Parent <allisonp(a)world.std.com> wrote:
The big thing is to experiment. I've considered
doing a PDP-8E design
and each time I take out a fresh sheet of paper it ends up being a
16bit or even 24bit machine. a 24bit machine with the same format as
an 8 as some appeal.
Yes, but an 18-bit version of the PDP-8 has even more appeal, since that's
what a PDP-4/7/9/15 is.
More precisely, the PDP-5 and PDP-8 family architecture is a simplified
version of the PDP-4/7/9/15 family architecture. If you're comfortable
programming the -8, you'll love the -9 and -15.
Since I've never been able to find an intact PDP-15 (the first DEC 18-bit
machine to use ICs), I've thought about designing one in my copious free time.
As soon as I figure out where the heck the copious free time is; I seem to
have misplaced it.
I've got a PDP-15 reference manual around here somewhere that I'll
eventually scan and put on my web page.
Robert Supnik of Digital (now Compaq) has written some excellent simulators
that cover the DEC 12-bit, 16-bit (PDP-11), and 18-bit families, as well
as the Data General Nova:
ftp://ftp.digital.com/pub/DEC/sim/
Cheers,
Eric