Reproducing old machines with newer technology (Re: PDP-12 at the RICM)

ben bfranchuk at
Tue Jul 14 12:35:16 CDT 2015

On 7/14/2015 11:17 AM, Chuck Guzis wrote:
> 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.

For the moment you can still get FPGA boards with expansion conectors.
The $39 card the trend nowadays. Hard to get real I/O of any kind as we 

> 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.

Since when was that new in electronics. Mind you New Electrostaic speakers
and OLD Quad II's go well together.

> 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?

Don't look at me, I lost the bid some old IBM equipment years ago.

> 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.

You can still the old computer blinking lights movie props.

> --Chuck

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