MOS Technology file format

The MOS hex format is a file format that conveys binary information in ASCII text form.

History

The KIM-1 single-board computer specified a file format for magnetic tape and a format for paper tape. The paper tape format was adaptable to other ASCII file formats, and is used for computers based on the MOS Technology 6502 microprocessor.

Format

Records begin with a semicolon (;), followed by two hexadecimal digits denoting the length of the data in the record. The next two bytes represent the starting address of the data, in big-endian (most-significant byte first) hexadecimal. Up to 24 bytes of data follow. Then, there is a 2-byte (4-character) checksum, a carriage return (<CR>), and a line break (<LF>). Finally, the record ends with six null characters (<NUL>).

The last record on the paper tape is empty (its length field is 0000), with the starting address field representing the total number of data bytes contained in the transmission. The file ends with a XOFF.

See also

• Binary-to-text encoding, a survey and comparison of encoding algorithms
• Intel HEX
• Motorola S-record hex format
• Tektronix hex format