M-1127 Sep61

This permanent memorandum, dated September 26, 1961, from S. Lambert (approved by Harlan E. Anderson), establishes standardized symbol conventions and program format for PDP-1 Maintenance programs. The need for this standardization arose from the large number of individuals involved in writing and checking out these programs.

The document mandates the use of specific symbols for small routines written in FRAP language:

• be (xx): beginning of program
• fi (xx): end of program
• eh (xx): error halt
• ph (xx): program halt (can be defined by fi (xx) if it's the end of the program)
• t (xx): temporary storage
• p (xx): reference symbol
• tb (xx): beginning of table

It also specifies a standard format for the beginning and end of all diagnostic routines, which includes initial lines for the test name, date, and author, followed by specific code blocks like bel szs 10, hlt, the program body, and a concluding section with fil szs 20, jmp bel, and other instructions for proper program termination and restart. A sample program is included to illustrate these guidelines.