MOS Technology Paper Tape Format

The following information is taken from the KIM-1 User Manual, published in August 1976 by MOS Technology, Inc. of Norristown, PA. It appears as Appendix F of the KIM-1 manual and is reproduced here exactly as in the original.

PAPER TAPE FORMAT

The paper tape LOAD and SAVE routines store and retrieve data in a specific format designed to insure error free recovery. Each byte of data to be stored is converted to two half bytes. The half bytes (whose possible values are 0 to FF_HEX) are translated into their ASCII equivalents and written out onto paper tape in this form.

Each record outputted begins with a ";" character (ASCII 3B) to mark the start of a valid record. The next byte transmitted (18_HEX) or (24₁₀) is the number of data bytes contained in the record. The record's starting address High (1 byte, 2 characters), starting address Lo (1 byte, 2 characters), and data (24 bytes, 48 characters) follow. Each record is terminated by the record's check-sum (2 bytes, 4 characters), a carriage return (ASCII 0D), line feed (ASCII 0A), and six "NULL" characters (ASCII 00).

The last record transmitted has zero data bytes (indicated by ;00). The starting address field is replaced by a four digit Hex number representing the total number of data records contained in the transmission, followed by the records usual check-sum digits. A "XOFF" character ends the transmission.

;180000FFEEDDCCBBAA0099887766554433221122334455667788990AFC ;0000010001

During a "LOAD" all incoming data is ignored until a ";" character is received. The receipt of non ASCII data or a mismatch between a records calculated check-sum and the check-sum read from tape will cause an error condition to be recognized by KIM. The check-sum is calculated by adding all data in the record except the ";" character.

The paper tape format described is compatible with all other MOS Technology, Inc. software support programs.

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