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

Chuck Guzis cclist at
Tue Jul 14 20:31:08 CDT 2015

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...


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