« Univac Document Archive: 1107 EXEC II Manual Added | Main | Marinchip Systems: Three New Documents »

Tuesday, December 5, 2017

Univac Document Archive: 1107 FORTRAN Programmer's Guide Added

I have added the following document to the Univac 1107 section of the Univac Document Archive. This is a PDF of a scanned paper document in my collection. This document is more than fifty years old (published in 1966) and may appear wonky to contemporary eyes: text is sometimes misaligned on the page and multiple fonts are intermixed like a ransom note. These are not artefacts of scanning—it's how the document actually appears. Recall that only around 38 Univac 1107s were sold, so documents describing it were produced in small numbers and didn't, in the eyes of Univac, merit the expense of the high production values of contemporary IBM manuals.

Univac 1107 FORTRAN was developed by Computer Sciences Corporation (CSC) and then maintained and extended by Univac programmers. It is based upon the dialect of Fortran which IBM originally released in 1965 under the name FORTRAN IV. This dialect, with a few minor changes, was standardised in 1966 as X3.9-1966 FORTRAN 66 by the American Standards Association (now ANSI), but many people continued to refer to it as FORTRAN IV. The CSC/Univac implementation is essentially compatible with FORTRAN 66 and IBM FORTRAN IV. Many Univac customers referred to the compiler as FORTRAN IV, although Univac never called it that.

This is the manual from which, along with Daniel McCracken's A Guide to Fortran IV Programming, I learned Fortran programming fifty years ago. The manual was intended as an introduction to the Fortran language and informal reference. It is a companion to U-3569, Univac 1107 FORTRAN Programmer's Reference Manual, of which I do not have a copy (and can't recall having ever seen).

The manual contains two sample programs: a simple iterative approximation program and a sort subroutine. Of course I had to type them in and see if they'd work more than half a century later. They both did, although the sort subroutine required a few minor syntactic tweaks. You can download an archive containing source code for these programs. See the README file in the archive for details.

When the Univac 1108 was released, the Fortran compiler was modified to exploit the 1108's new instructions, in particular native hardware support for 72-bit double precision floating point arithmetic (the 1107 compiler supported double precision with a different format implemented in software). The language was extended to include some additional features such as the PARAMETER declaration. Univac called this compiler FORTRAN V, and it remained the standard FORTRAN for the 1100 series until the introduction of ASCII Fortran, which was compatible with the FORTRAN 77 standard and used the ASCII character set.

Posted at December 5, 2017 16:26