Doug McIlroy

At the suggestion of Tom Van Vleck, I sent Doug McIlroy an email asking if he’d run across the Fortran ‘Tome’ while at Bell Labs in the 1950s. He replied:

I was at MIT when the first Fortran came out, and I don’t recall seeing the source there. When I joined Bell Labs in 1958, we had Fortran II. We had the source; in fact Dolores Leagus had worked with IBM on adapting the compiler to use a full 32K-word memory, and had subjected the compiler to the BESYS operating system (the compiler was a standalone program as it came from IBM). If you can find her (she retired about the same time I did) she might know where to look.

I myself used the Fortran source only after we got the 7094, and I know that had been altered significantly, for it used 709 opcodes that didn’t exist on the 704.

Another document that come with Fortran, which everybody got to know was the “stop book”. The compiler did not issue diagnostics. Instead it halted. The machine operator would record the IC from the console lights. The stop book told what the cause of each stop was, often very cryptically: “trouble in the tag table, or some other cause”. You should try to collect that, too. One of the things Dolores did was to replace the halt instructions by system calls, so the stop could be recorded automatically.