They say the best way to understand how a system works is to put it on paper, and computing is no exception. We've seen paper binary calculators and paper processors, but what about a complete computer simulator? That idea takes us back to the late 1960s, when Bell Labs developed CARDIAC, an "illustrated computational assistant" with its own processor and memory cells. For obvious reasons, original CARDIACs are almost impossible to find, but today we can create very faithful replicas...
A Brief History
Getting a computer these days is relatively easy. It doesn't need to be state-of-the-art, and the second-hand market always has some bargain. But there was a time when computers were beyond the concept of a "personal item". They were exclusive to laboratories, universities, and large companies. Multiple projects competed for time, and to be more efficient, one had to prepare "the old-fashioned way": with pencil and paper.
This sparked the creation of several educational kits, with the goal of teaching students essential information about how computers work and how they should be programmed. Last August we explored the GENIAC from 1955 with an original cost of $20. However, in the late 1960s, many schools in the United States and Canada got access to CARDIAC, the "CARDboard Illustrative Aid to Computation", created by David Hagelbarger of Bell Labs.
How the CARDIAC Works
In relaxed terms, the CARDIAC is a card that has a "CPU" on the left side and memory banks on the right. The design is not particularly intuitive, and the official manual exceeded 50 pages divided into 16 sections, but once mastered, the user could decode instructions by moving sliders, move the program counter from one memory section to another, and replicate the task of an arithmetic-logic unit, among other things.
Building Your Own
Now, getting an original CARDIAC is very difficult at best. After all, "paper simulators" were not meant to last long. But Instructables user "megardi" (real name Michael Gardi) decided to share with the public instructions for creating almost exact replicas of the CARDIAC. If the name sounds familiar, it's because he's the same user who made the aforementioned GENIAC.
The necessary materials are reduced to a printer, seven sheets of "heavy" paper (200 grams or more), a good pair of scissors, and glue. All files are in SVG, so we can modify the scales as we like. Additionally, if you have the privilege of a laser cutter, you can download the DXF files and make the cuts with much higher precision. Weekend project? You decide.
Access the tutorial: Click here
