Modula-2

Modula-2 is a computer programming language designed and developed between 1977 and 1985 by Niklaus Wirth at the Swiss Federal Institute of Technology in Zurich (ETH Zurich) as a revision of Pascal to serve as the sole programming language for the operating system and application software for the personal workstation Lilith. The principal concepts were:

Modula-2 was viewed by Niklaus Wirth as a successor to his earlier programming languages Pascal and Modula. The language design was also influenced by the Mesa language and the new programming possibilities of the early personal computer Xerox Alto, both from Xerox, that Wirth saw during his 1976 sabbatical year at Xerox PARC. The computer magazine BYTE devoted the August 1984 issue to the language and its surrounding environment.

Description

Modula-2 is a general purpose procedural language, sufficiently flexible to do systems programming, but with much broader application. In particular, it was designed to support separate compilation and data abstraction in a straightforward way. Much of the syntax is based on Wirth's earlier and better-known language, Pascal. Modula-2 was designed to be broadly similar to Pascal, with some elements and syntactic ambiguities removed and the important addition of the module concept, and direct language support for multiprogramming.

Modula-2+

Modula-2+ is a programming language descended from the Modula-2 language. It was developed at DEC Systems Research Center (SRC) and Acorn Computers Ltd Research Centre in Palo Alto, California. Modula-2+ is Modula-2 with exceptions and threads. The group who developed the language was led by P. Rovner in 1984.

Main differences with Modula-2:

Implementations

Modula-2+ has been used to develop Topaz, an operating system for the DEC SRC Firefly Multiprocessor. Most Topaz applications were written in the Modula-2+ programming language which grew along with the development of the system. Also to build a programming environment for it in the Acorn Research Center ARC. The language has now completely disappeared but was of great influence to other programming languages such as Modula-3.

The original developers of Modula-2+ were both bought; Acorn by Olivetti and Digital Equipment Corporation by Compaq. Compaq itself was bought by Hewlett-Packard. Olivetti also sold the Olivetti Research Center and Olivetti Software Technology Laboratory (after bought Acorn ARC) to Oracle and was later absorbed by AT&T. DEC have made the SRC-reports available to the public.