I'm missing something in this discussion, I think.
HDL's (take your pick) are just programming languages like FORTRAN or C
with different constraints. What's the point of going to all the
trouble of doing an FPGA implementation of a slow old architecture, when
pretty much the same result could be obtained by running a software
emulator? Neither accurately reflects the details of the real
thing--and there will always be the aspect of missing peripherals.
Perhaps the worst aspect of using FPGA is that this is a rapidly moving
field, so that the part you used to do your implementation 10 years ago
will no longer be available. I've done a few designs using 5V CPLDs
(XC95xx series) not *that* long ago. Now they themselves are quaint
examples of obsolete hardware. You can't win.
You can move software-only simulators quite easily, but I'm not as
sanguine about FPGA designs.
And you still don't have the peripherals. I suppose one could emulate a
Univac Solid State machine in FPGA, but what would one do about the
all-important drum coupled to the card reader and printer. Has anyone
rolled out a design for a DIY 1403 printer?
I've run the Cyber emulator as well as various SIMH emulators from time
to time, but it's just not the same as the real thing--it's not even
remotely the same.
--Chuck
