Suramya's Blog : Welcome to my crazy life…

November 4, 2014

A Cardboard Computer that actually works

Filed under: Computer Hardware,Interesting Sites,Techie Stuff — Suramya @ 12:31 AM

No, this is not a joke or a toy for a 5 year old. In the 70’s the computers were still not in the affordable range for 99% of the population so a bright chap by the name of David Hagelbarger working at Bell Laboratories designed CARDIAC (CARDboard Illustrative Aid to Computation) as an educational tool to give people without access to computers the ability to learn how computers work. Basically it is a micro-processor made out of cardboard.

The CARDIAC computer is a single-accumulator single-address machine, which means that instructions operate on the accumulator alone, or on the accumulator and a memory location. The machine implements 10 instructions, each of which is assigned a 3-digit decimal opcode. The instruction set architecture includes instructions common to simple Von Neumann processors, such as load, store, add/subtract, and conditional branch.

Operating the computer is fairly simple–the cardboard slides guide you through the operation of the ALU and instruction decoder, and the flow chart shows you which stage to go to next. The program counter is represented by a cardboard ladybug which is manually moved through the program memory after each instruction completes.

Even though the CARDIAC is dated and very simplistic, it is still a useful tool to teach how microprocessors work. Although modern processors include multi-stage pipelines, finely-tuned branch predictors, and numerous other improvements, the basic principles of operation remain the same

You can print your own by visiting Kyle Miller’s Site. More information about CARDIAC and how to use it is available at cs.drexel.edu and on it’s Wikipedia site.

Thanks to Hackaday.com for the story.

– Suramya

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