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

Jay Jaeger cube1 at
Tue Jul 14 20:55:14 CDT 2015

Meh.  You take your machines and I'll take mine. :)  The IBM 1410 is a
machine I know well, so I know how it is supposed to work, and I have
detailed information in the form of the ALD's and the CE training
materials to go with it, plus software including diagnostics and
operational software I can test it with.  So I have a way to verify the
functional correctness of the reproduction.

Architecturally, it was pretty much the last of its kind: the last of
the BCD decimal arithmetic machines, which also makes it interesting.
It has also become much more obscure than the 1401, which it followed,
because not nearly as many were made and sold.

Software wise, the PR-155 OS for the 1410 was pretty decent for a design
that started in the early 1960s.  It could do multi-programming, both
for I/O spooling operations and for tele-processing, with swappable
transient TP programs along side batch operations, if you had the
memory.   The machine I worked on was only 40,000 BCD characters, but
ran the full operating system (sans TP).

Dumb channels though (simple FSM's - no program-ability), which kept the
size of the machine and its cost down.

More below.


On 7/14/2015 8:31 PM, Chuck Guzis 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?

I am not interested in recent.  Indeed, if I did anything after the
1410, I'd probably go sideways or backwards in time.  I'll leave them to
you.  ;)

> 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)

No, you are correct.  This has nothing to do with the state of the art.
 This is a hobby/historical documentation effort.  But as I mentioned in
the earlier note the "how they worked" comes in levels, and my effort is
at a lower level of abstraction / higher level of detail.

>> 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.

To each is own.  Enjoy.

>> 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.

Well, if I had more money I might have snagged a CDC-160A a few years
back (it went for over twice what I could afford at the time - I maxed
out at $2k), and I'd probably be doing that one, but, such is life.

> 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.

The PDP-8 variants are popular with collectors for a number of reasons.
 Approachable physical size is one.  Ordinary TTL is another.  Speeds
that folks can deal with and lack of overall complexity is yet another
reason.  A console that can help debugging is yet another. The first
machine in my collection is a PDP-8/L for all of those reasons.

(Interestingly, the IBM 1410 console tells much more about what is going
on in the machine that might be at first apparent - the entire machine
state (aside from memory) is pretty much there, but presented in a way
that is quite different than what one sees on a PDP-8)

RE DECStaions: I think what you mean are the DECMates, but yes: they
indeed used the Intersil chip sets.

> 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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