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

Sean Caron scaron at
Tue Jul 14 20:49:28 CDT 2015

I think a lot of things drive the popularity of the PDP-8 from nostalgia to
historicity to perhaps the relative simplicity of the CPU to understand as
a design example in computer architecture ... IMO the machine is just a bit
too limited to be much fun to program in assembly ... although maybe some
are attracted to the "challenge" :O

But certainly a PDP-8 or PDP-11 for that matter would have been much more
common in the field; much more possible for someone to get their hands on
in some kind of nominally working condition; much more affordable; easier
to digest than a large mainframe or supercomputer. It's a shame more
examples of these machines haven't been preserved but in many cases, there
weren't many examples produced in the first place ... as well, I think a
lot of the mainframe vendors took a "scorched earth" policy and tried to
destroy as much of the older equipment as possible ... to keep it off the
gray market.

Many examples of blinkenlights eye candy throughout computer history but as
far as supers go, I think the CM-5 ranks pretty close to the top for me :O



On Tue, Jul 14, 2015 at 9:31 PM, Chuck Guzis <cclist at> wrote:

> On 07/14/2015 04:49 PM, Jay Jaeger wrote:
>  Not necessarily.  For example, it is impossible to find an IBM 1410, as
>> far as I know.  But there ARE 1415 consoles I knew of a while back, and
>> there are certainly 729s and 1403 printers and 1402 card read/punch
>> units up and running.
> There are plenty of machines that are impossible to find.  And many that
> are gone that are quite novel.  That IBM sold so many is something in their
> favor, but how about a working Saxpy box--which is quite a bit more recent
> than your 1410?  Or the STAR-65, 1B or even -100.  The only 65 was moved
> from Canada and scrapped.  My department had the only two 1Bs and I saw
> those go under the sledgehammer and bolt cutters. I don't think that there
> are STAR-100s of any stripe (plain, -A, -B or -C) left--they were just too
> big.  Are there any BSPs or ASC's kicking around?
> There are tons of lost non-IBM peripherals.
> But we do have documentation on many of these things, so at least we know
> "how" they worked.  And I submit that in the long run, that's what
> matters.  There's very little relevant to the state of the art today that
> really matters. (Boy, am I going to get flamed on that)
>  Software "just make it work" emulator.  (Most of SimH stuff seems to be
>> at this level).
> Or dedicated simulators (non-SIMH).  Often, all you have is the system
> documentation that talks about the instruction set and a few binary files.
> Reverse-engineering can be fun and valuable.
>  That is why I use VHDL (or Verilog is fine to).  So that those models
>> are portable into the future.   The FPGA part doesn't matter so much,
>> but the model future portability does matter.
> Maybe, but I'd rather read the design documents than a pile of HDL of any
> stripe.
>  1403's and IBM 729's and 1402 card read/punch still exist.  I seem to
>> recall the CHM doing something like building a 729 tape drive tester, too.
> But there were LOTS of those.  Try something non-IBM and very obscure.
>  But something like the SBG 6120 PDP-8 is closer, potentially with real
>> lights and switches.  As another I example, I can envision an FPGA
>> sitting inside a real IBM 1415 console, running it's lights, responding
>> to it's switches and interacting with it's selectric typewriter.
>> Probably more than I will accomplish, but it is good to have goals.
> A PDP-8 is a simple CPU, probably popular because of the lights and
> switches. I see evidence that these were eye candy--the DECStations are
> practically the same thing, but apparently not nearly as desirable.
> Seymour Cray should have used kinetic sculptures on his machines as part
> of eye candy, I guess. Or maybe more chrome...
> --Chuck

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