Modula-3 History Collection on Computer History Museum

Summary

Modula-3 History Collection Paul McJones, editor paul@mcjones.org https://mcjones.org/dustydecks/ Last updated 5 July 2026 Abstract This is an annotated collection of documents, source code, and other materials concerning the birth, development, and use of the Modula-3 programming language. Contents Acknowledgments Thanks for help, advice, and/or materials from Marc H. Brown, Luca Cardelli, Michel Dagenais, Dave Detlefs, John DeTreville, Amer Diwan, Jim Donahue, Allan Heydon, Tony Hosking, Bill Kalsow, Al Kossow, Rustan Leino, Eliot Moss, Eric Muller, Farshad Nayeri, Mika Nyström, John Polstra, Klaus Preschern, and Olaf Wagner. This web site is dedicated to the designers of Modula-3 and its predecessor languages and to the authors of all the libraries and applications written in Modula-3. Introduction Modula-3 is a programming language designed in the late 1980s by Luca Cardelli, Jim Donahue, Mick Jordan, Bill Kalsow, and Greg Nelson (the defining report was written by Lucille Glassman and Greg Nelson). It is intended to be both safe and efficient for a wide range of systems and application programming: from low-level code like device drivers to program development tools to scientific or business applications. Safety means the runtime state of a program is guaranteed to be faithful to the language semantics. Modula-3 was also intended to be as simple as possible given these goals; the designers exceeded their 50-page budget for the language definition by only six lines of text plus the syntax summary. The language features include interfaces, objects, generics, threads, isolation of unsafe code, garbage collection, exceptions, and subtyping. Many of these have become more widespread by 2025, but in 1990 [Nelson1991] it was much less common, especially in a language supporting non-heap allocated data structures. Modula-3's existence stems from a suggestion by Maurice Wilkes to Niklaus Wirth that Modula-2+ be revised and standardized as Modula-3. (Modula-2+ extended W...