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→Autocoder as implemented on the IBM 1401: Correction: "word mark" incorrectly named "byte mark." The byte was only introduced on the IBM 360, a 1401 successor. Tags: Mobile edit Mobile web edit |
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and transformed them into the instructions the machine recognized. It supported [[conditional branching]], named [[subroutines]], counting [[iterations]], and what IBM called its [[Advanced Programming Feature]], an optional feature involving three separate bytes between ___location 80 and 90. (Since memory locations 0-79 were reserved for the card reader, 100-179 for the card punch, which punched a card with the data in these locations when the "punch" command was issued, and 200-279 for the (single) printer, locations 80-99 were orphans and available for other purposes that only needed a few bytes.)
At that time the primary storage media was half-inch magnetic tape read and written on drives the size of refrigerators. There were no named files, a concept still in the future. Autocoder did implement a new feature: the
The 1401 was available in six memory configurations, with 1400, 2000, 4000, 8000, 12000, or 16000 six-bit characters. The 8000-character model was the minimum needed to run Autocoder; a character file (on punched cards or magnetic tape) could be produced on an 8000-character model which could then be run on a 4000-character machine.
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