Paper Computer

CARDIAC, I had one in high school, too:

Marc

Had you said "cardboard", you would have had it in 1.

In the early 80th there was a German "Papiercomputer" The web site is German only.

Now, after the year 2000, a PC simulation for it is available, see buttom of the page.

Regards Heinz

PS. Never worked with it. It was a West German product and may be on an embargo list for East Germans

Nice link!

Ed

Not a cardboard one, but a plastic mechanical computer, the "Digicomp-1":

I'e seen them on eBay, though none now.

Nope, it's definitely the Cardiac that I remember -- although maybe I should have one of each?

You can never have too much computing power. Didn't they teach you that in school?

-- Ray

Cardiac? I recorded a presentation about Cardiac at a Forth Interest Group meeting years ago. Here is a 13 minute video on the Cardiac cardboard computer. The soundtrack is a bit noisy as the camcorder was about worn out by that time. I don't know if it is the paper computer that you remember or not

Best Wishes

Google Video isn't working for me (hangs without ever loading the flash file) on my browser and there is no direct link available to download the file. Would you consider emailing it in whatever form you originally uploaded it to Google?

Regards,

Michael

I see you have lots of good suggestions.

Another option would be to explain how a PDP 8 minicomputer executes instructions. I've found that a reasonably intelligent person with mininal computer background can understand PDP 8 machine language (less indirect and autoindex instructions) with about 2-3 hours of explanation.

There are also some free sims for PDP 8's.

That's an interesting suggestion. Particularly in light of the fact that my wife's first job out of college (actually the job that is partially responsible for her never _finishing_ college) was assembly language programming for either the PDP-8 or the PDP-11. The nostalgia would be thick enough to cut.

I may take your suggestion, but replace "PDP-8" with "PIC", "AVR", or "68HC08" -- not because I think they'll be better, but because once he learns it I can present him with a board and processor that he can play with directly.

One other approach is to take an instruction set like the

For example the 6808 can be fully functional without support for page 0 memory, move instructions, compare and branch instructions, and test instructions.

The result is a very manageable instruction set that is a lot easier to explain. This can even be done in layers by initially not documenting indexed instructions.

The major drawback of the PDP8 instructions set is the code is expected to run in writable memory as way of returning from subroutine calls.

Regards

-- Walter Banks Byte Craft Limited Tel. (519) 888-6911 Fax (519) 746 6751

And exactly the same goes for 8080 code, with the possible advantage that he can see how it expands into a wide spectrum of software (CP/M) and even an operating system. Actually, you can't get an 8080 any more, but any Z80 will execute all the instructions, and peculiarities don't show up until you get to the Z80 set and fitting everything in. The Z180 (or 64180) even expands the memory accessibility to 1 megabyte. So this starts from a sound (8080) instruction set, with two expansion levels. And a large extent of available software.

The 6809 is probably the all-time great processor design for teaching purposes and you can probably find computers and programming tools for next to no cost or free from those who have them sitting in storage somewhere. Mr. Banks may even have a C compiler around somewhere.

The 68HC12 is also good as long as you stay away from the exotic instructions.

A most interesting thread, and I've enjoyed reading/studying all of the replied links.

While a tactical demonstrator such as the CARDIAC is ideal, some related topics occured to me that others may find interesting:

1. The 16Fxxx series of Microchip brand RISC microprocessors have a very small instruction set - only about 37 instructions and a Harvard architecture.
2. The basic HP Calculators (HP48 and HP35s) are stack based and programmable machines that have a very simple architecture. The HP35s is a relatively low cost (under 60USD), 4 level stack RPN machine with over 32K of RAM (for program and data memory), 26 alpha- adressed data memories and several hundred index-addressed data memories. The HP48 is a more general (out of production, but easily available on ebay), stack based RPL machine (very similar to FORTH) with a graphic display and RS232 and IR interfaces.

TomCee (former Detroit, USA FIG Administrator)