• Anonymous. FORTRAN I, II, and 709 : Customer Engineering Manual of Instruction. IBM Corporation, Form R23-9518-0, February 1959, 67 pages. Copy belonging to Mark Halpern. PDF

This document is filled with useful information for anyone interested in digging into the IBM Fortran I/II compiler, and provides fascinating hints about what it was like to be a customer engineer in the late 1950s. It begins with an introduction to the nature of machine language, assembly language, and higher-level languages, starting with an analogy whose exposition would not be considered quite politically correct today: “The problems involved in man’s communications with the complex computer are in many respects similar to those problems involved with his communications with another man who speaks an unfamiliar language.” The next chapter jumps right into the structure of the compiler with summaries of each of the sections (passes). This is followed by a description of the Fortran systems tape, which performed the functions we now associate with an operating system. Section 1.12.00, Service Aids, notes: “To successfully run the Fortran translator the 704 must be in in prime working order. The tape system in particular, and the drum are given a good work-out during the exeuction of the program.” It goes on to list adjustments and engineering changes that were likely to be required to run such a demanding program as the Fortran compiler. Another chapter describes the various tables used to represent the intermediate and final object program.

I was able to scan this document courtesy of Mark Halpern, whose first assignment after joining the IBM Programming Research Department in 1957 was to study and document (via flow-charts) the Fortran compiler. Mark’s memoirs were published in three parts in the Annals of Computer History starting in 1991; eprints are available online at Mark’s web site.

Postscript (March 20, 2006): I should have noted a fascinating memoir by John Van Gardner, who was one of the IBM Customer Engineers who installed IBM 704 serial number 13 at Lockheed Aircraft in Marietta, Georgia in May 1956. This memoir describes the resourceful techniques he used in 1957 to debug a hardware problem that resulted in the Fortran compiler behaving in a nondeterministic manner.

This listing complements the later 32K 709/7090 FORTRAN II (scroll down a bit from here from the IBSYS distribution on 7-track tape digitized by Paul Pierce. This version runs on the bare IBM 704, whereas the later version, for the IBM 709 with its more sophisticated I/O system included a Fortran Monitor System, which had been adapted to work with IBSYS.

Rob suggested others might want to get additional programs running on the emulator, and suggested several that are available. Leif Harcke suggested CTSS (M.I.T.’s Compatible Time Sharing System), using the tapes available from Paul Pierce’s collection. I mentioned this to Tom Van Vleck; he took a look at the tapes and lent his enthusiastic support. Rob is happy to make the necessary “hardware modifications” (known as RPQ’s) to the emulator if someone will supply him with a specification.

Updated 23 Mar 2006: Leif Harcke’s URL changed.