Punched Cards

Douglas W. Jones
University of Iowa Department of Computer Science
Punched cards were, in the 1960's the universal symbol of computing, and even in the 1930's, they were a symbol of modernity. Today, cards are all but forgotten, surviving in a few applicatons such as turnpike toll receipts and automatic voting systems.

Historical Information

Codes used on Punched Cards

There were multiple mappings between the 12 holes of one card column and the character sets of various machines and keypunches.

Punched Card Emulation

The following software is available to encourage the development of museum quality emulators for antique computing and punched-card tabulating equipment:

These are supported by a shared translation table that includes some of the many mappings between ASCII and hole patterns punched on cards.

The file format used by these programs is available, and I hope that emulators for historical computer architectures will support interchangable punched card I/O using this format and that a suite of emulated punched card data processing machines will be developed.

Other punched card resources