CARDIAC.mdwn (1648B)
1 CARDIAC (CARDboard Illustrative Aid to Computation) is a learning aid developed by David Hagelbarger and Saul Fingerman for Bell Telephone Laboratories in 1968 to teach high school students how computers work. 2 3 The kit consists of an instruction manual and a [[paper computer]]. 4 5 The computer operates in base 10 and has 100 memory cells which can hold signed numbers from 0 to ±999. It has an instruction set of 10 instructions which allows CARDIAC to add, subtract, test, shift, input, output and jump. 6 7 ``` 8 INP(Input): take a number from the input card and put it in a memory cell. 9 CLA(Clear&Add): clear the accumulator and add the contents of a memory cell to the accumulator. 10 ADD(Add): add the contents of a memory cell to the accumulator. 11 TAC(Test accumulator): performs a sign test on the contents of the accumulator; if minus, jump to a specified memory cell. 12 SFT(Shift): shifts the accumulator x places left, then y places right, where x is the upper address digit and y is the lower. 13 OUT(Output): take a number from the specified memory cell and write it on the output card. 14 STO(Store): copy the contents of the accumulator into a specified memory cell. 15 SUB(Subtract): subtract the contents of a specified memory cell from the accumulator. 16 JMP(Jump): jump to a specified memory cell. 17 HRS(Halt&reset): move bug to the specified cell, then stop program execution. 18 ``` 19 20 ## Relevance to permacomputing 21 22 This project, and others like it, were offering a conceptual computer that could be understood in its entirety by a single person. 23 24 See also: 25 26 * [On Wikipedia](https://en.wikipedia.org/wiki/CARDboard_Illustrative_Aid_to_Computation)