Pascal (ISO 7185:1983)

Compared to C, the original Pascal language had some rather idiosyncratic restrictions, which made it difficult to write real programs in. It was clearly intended to be for learning how to program.

More information in the ISO 7185 Standard.

OS-9 Pascal

OmegaSoft Pascal was developed starting in 1979 for the Motorola 6809 Processor. It was ported to MDOS, FLEX and OS-9. The original designer was Certified Software Corporation.

Microware Pascal was originally developed by Iowa Mountain Software and is a very thorough implementation of the language according to ISO Standard 7185.1 level 0. It has a few extensions: CASE statements can have an OTHERWISE option; bit-by-bit Boolean operators are included ('&', '!' and '#').