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Paper Computer

Discussion in 'Electronic Design' started by Tim Wescott, Jan 19, 2008.

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  1. Tim Wescott

    Tim Wescott Guest

    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.

    --
    Tim Wescott
    Control systems and communications consulting
    http://www.wescottdesign.com

    Need to learn how to apply control theory in your embedded system?
    "Applied Control Theory for Embedded Systems" by Tim Wescott
    Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
     
  2. Marc Ramsey

    Marc Ramsey Guest

    CARDIAC, I had one in high school, too:

    http://www.larkfarm.com/cardiac_answers.htm

    Marc
     
  3. JeffM

    JeffM Guest

  4. John Fields

    John Fields Guest

    ---
    See:

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

    page 80.

    The rest is excellent, also.

    JF
     
  5. In the early 80th there was a German "Papiercomputer"
    The web site is German only.
    http://www.wolfgang-back.com/knowhow_home.php

    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
     
  6. ehsjr

    ehsjr Guest

  7. krw

    krw Guest

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

    http://www.retrothing.com/2006/02/build_your_own_.html

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

    Tim Wescott Guest

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

    --
    Tim Wescott
    Control systems and communications consulting
    http://www.wescottdesign.com

    Need to learn how to apply control theory in your embedded system?
    "Applied Control Theory for Embedded Systems" by Tim Wescott
    Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
     
  9. Ray Haddad

    Ray Haddad Guest

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

    Anonymous. Guest

    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?
     
  11. Jeff Fox

    Jeff Fox Guest

    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

    http://video.google.com/videoplay?docid=-8058767226095640627

    Best Wishes
     
  12. msg

    msg Guest

    Jeff Fox wrote:
    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
     
  13. Jim Stewart

    Jim Stewart Guest


    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.
     
  14. Tim Wescott

    Tim Wescott Guest

    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.

    --
    Tim Wescott
    Control systems and communications consulting
    http://www.wescottdesign.com

    Need to learn how to apply control theory in your embedded system?
    "Applied Control Theory for Embedded Systems" by Tim Wescott
    Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
     
  15. Walter Banks

    Walter Banks Guest

    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
    http://www.bytecraft.com
     
  16. CBFalconer

    CBFalconer Guest

    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.
     
  17. Bill

    Bill Guest

    Well, I suppose RTFM would be inappropriate at this point <g>,
    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.
    :eek:)
    Bill
     
  18. 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.
     
  19. Alex Colvin

    Alex Colvin Guest

    The plastic slides would jam; perhaps if self-lubricating PTFE
    clearly a service pack is due...
     
  20. Rich Grise

    Rich Grise Guest

    .
    So go to the office supply store or stationer and get a box of
    assorted rubber bands. If you find one that works, either find
    enough in the box, or go specifically buy more of that size. :)

    If you don't find one the right size, you could probably shorten
    an oversized one with a judicious application of scissors and
    stapler. :)

    Good Luck!
    Rich
     
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