| |
| | Doug Jones's punched card codes |
 | | IBM's BCD codes were all more complex, partly because of a desire to represent the numeral zero with the 6-bit numeric code 000000 (in the IBM 704, 709, 7040 and 7090) or with 001010 (in the IBM 705, 7080, 1401, 1410 and 1414). |
 | | The IBM model 026 keypunch, introduced in July 1949, was the workhorse of much early work in business data processing, and although it was incapable of automatically punching the large character set required by most programming languages, many model 026 punches remained in use into the early 1970's. |
 | | Given the sparse nature of the IBM 026 character set and the larger character sets supported by printers of the era, many computer manufacturers developed proprietary extensions of their own, some with a great degree of compatability with IBM's later character set extensions, and some with little or no compatability. |
| www.cs.uiowa.edu /~jones/cards/codes.html (2243 words) |
|