My First Computer – the DIGI-COMP 1

Posted by on January 30, 2015 in Fun, Programming | 1 comment

My First Computer – the DIGI-COMP 1

Oftimes those of the computer nerd persuasion like to talk about how they got hooked by these “thinking machines.” The “kids” may talk about their first Macbook Pro. Senior kids will poo-poo that and mention their Gateway 2000, Mac LC or even the Apple IIGS.

Othermore grizzled veterans will shake their collective heads and whisper “amateurs” followed boasting about their Woz-signed Apple II, Commodore 64 (The Coleco Adam guys just slip quietly out of the room when this discussion starts).

Then there’s me.

Detailed Digicomp illustration

My first computer was a 3-bit mechanical plastic thing called the DIGI-COMP 1. Billed as the “First real operating digital computer in plastic” it was a brilliant little piece of engineering, measuring about 12” long and 4” high and cost a whopping $4.95. It came with coding sheets, a manual explaining binary arithmetic and a dozen or so experiments doing everything from up and down counters to adders and multipliers. Of course, the precision was a bit limited as after all, it was only a 3-bit system. No floating point, graphics GPU and the UI was a small window showing nothing but the binary output.

Programming was accomplished by using “logic tubes” that fit over various pegs on the different flip-flops (betcha you haven’t heard of flip-flops for a long time). The program was advanced by the manually operated clock, running at about .5 to 1 hz, cycled by hand.

The DC1 came out in 1963. Computers and the space-age held much of the national attention during that time, so any technically oriented toys were popular. (anyone remember “Things of Science?”) Billed as an educational-toy, the DC was manufactured by a company called ESR, or Educational Science Research, Inc. Designed by three engineers outside of their day jobs, the little computer became a hit in the Christmas of 1963.

I learned Boolean logic from the DC1, and managed to have kept my original manual, even after the computer had an unfortunate accident with a cherry bomb one July 4. The manual’s graphics are pure early 60’s using duotone wash. (If you’ve watched Madmen on A&E, you’ll see very similar artwork in the first couple of seasons when various ad campaigns were being discussed.) Considering it was 1963, the any illustrations were of Atlas missiles and Mercury spacecraft.

If you want to experience this little machine yourself there you can go to eBay where DCs typically go for about $150. Another way is to check out MindsOnToys, which introduced the DIGI-COMP 1, v. 2.0, in 2006. Considerably less than the eBay originals, v 2.0 was produced out of die-cut foam core and cardboard for only about $60. Unfortunately the friction from the cardboard makes it fairly difficult to cycle, but still is a welcome decoration on my desk, next to a Cray-3 board and some Apollo Guidance Computer rope core memory modules.

For more information, check out the Friends of DIGICOMP, and there have been DIGI-COMP emulators on the web at some point, but none of them seem to be up at the time being.

DIGI-1 and an iPad

DIGI-1 and an iPad

1 Comment

  1. I still remember when my dad brought home a MiniVac 601 (Scientific Development Corp.). It was actually ELECTRIC (DC adapter was inside the machine). It had what was essentially 6 columns: Top row was six lights, next row down was 6 relays, next row down was 6 manual slide switches mounted horizontally, and I-don’t-remember how may other rows of pin sockets beneath the slide switches. To the right and bottom row was a rotary dial (which one could program to run either clockwise or counter clockwise. The whole machine was about 24 inches wide, 4 inches high on the front, and 6 inches high in the rear. The top panel of this ”giant breadboard” was about 16 inches from front to rear.

    My siblings and I spent countless hours ”programming” this ”marvelous toy” with the red and yellow jumpers. Eventually, our fun became a contest of who could program the thing to run the longest single loop. To my recollection, I won by making the rotary dial run back and forth at ever-increasing intervals with each pass. That poor motor was hardwired to run only as fast as ONE rpm. The fun came to a screeching halt, however, when the motor for the dial quit running. There was no longer anything to automatically make a program advance to the next step. I will never forget that day – the motor heaved its last sigh with a low grinding noise.

    All of our efforts with the MiniVac were not in vain: Older brother went on to do contract programming for Sperry Univac mainframes. His stint with Ma Bell garnered him a patent for ”using fuzzy logic” to determine how to shuffle assets (file servers) around when it came time for a hardware refresh (new machines).

    Younger brother whizzed through college to get his B.S. in Biology. Sister got a Bachelor’s, too, and ended up in purchasing for the shuttle program. And finally, me – I do hardware & software support for a medium-sized machine shop owned by a Fortune 500 company.

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