COMMENT ā VALID 00002 PAGES C REC PAGE DESCRIPTION C00001 00001 C00002 00002 NOTES ON PDP-10 MACHINE CODING. C00003 ENDMK Cā; NOTES ON PDP-10 MACHINE CODING. The actual machine codes 1. Letters: ASCII and SIXBIT. 2. Numbers: Integer and Floating. 3. CPU Instructions: Op codes 4. System instructions: UUO's IOT'S CALLI's 5. I/O processors: display formats.