Paper Computer

In high school, ca. 1976 or so, I learned how to program in assembly language on a "paper computer". It was basically a worksheet with a

10x10 "memory" that one filled in with two-digit numbers, a two digit "accumulator", and an easy to interpret "machine language" that you, the "central processor" was required to execute.

Does anyone else remember this critter? Anyone know where I could get my hands on one? I want to explain machine code to a 14-year-old.

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Tim Wescott
Control systems and communications consulting
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Tim Wescott
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CARDIAC, I had one in high school, too:

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Marc

Reply to
Marc Ramsey

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

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Reply to
JeffM

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See:

http://www.freescale.com/files/microcontrollers/doc/ref_manual/M68HC05TB.pdf?fsrch=1
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Reply to
John Field

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

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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

Reply to
Heinz-Jürgen Oertel

Nice link!

Ed

Reply to
ehsjr

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

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

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Keith
Reply to
krw

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

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Tim Wescott
Control systems and communications consulting
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Reply to
Tim Wescott

On Sat, 19 Jan 2008 17:35:02 -0600, I said, "Pick a card, any card" and Tim Wescott instead replied:

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

-- Ray

Reply to
Ray Haddad

I played with one of those in school in about 1968.

It wasn't well manufactured despite being an innovative idea.

The plastic slides would jam; perhaps if self-lubricating PTFE had been employed it might have been a different story?

Reply to
Anonymous.

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

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Best Wishes

Reply to
Jeff Fox

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

Reply to
msg

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.

Reply to
Jim Stewart

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.

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Tim Wescott
Control systems and communications consulting
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Reply to
Tim Wescott

One other approach is to take an instruction set like the

6808 and eliminate redundant instructions.

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

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Reply to
Walter Banks

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.

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 [mail]: Chuck F (cbfalconer at maineline dot net) 
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Reply to
CBFalconer

Well, I suppose RTFM would be inappropriate at this point , but the Assembly Instructions page does clearly mark two locations: "For smoother operation, lubricate with mineral oil"; and doing so actually made a big difference.

The lack of a replacement specification for the 8 rubber bands is the only thing that has kept mine out of service for the past 35 or so years. :o) Bill

Reply to
Bill

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.

Reply to
Everett M. Greene

clearly a service pack is due...

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	mac the naïf
Reply to
Alex Colvin

This is very nearly an assignment for a digital logic class I once had in college; it is an entertaining exercise and gets people to think about all the instructions they *don't* need (such as a specific instruction to zero a register when XOR Rn,Rn works, etc...).

Reply to
Joel Koltner

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