Many implementations of ML/I will have two distinct version identifiers. One will be the version of the core logic of ML/I, and the other will be a system-dependent value, relating to the machine dependent logic (input/output, etc.). This page is concerned only with the various versions of the core logic, and the features of each one. This should help when reading user documentation such as the ML/I User's Manual.

The version identifier for the core logic has a somewhat arcane format; it consists of three letters. The first letter indicates the source of the implementation (original language).

Possible values for the first letter are:

A

The source language was either L or LOWL; i.e. the logic was mapped from one of these. For more details, see How ML/I is implemented. Each language is given its own column in the table below.

B

The source language was BCPL; i.e. the logic was compiled from the BCPL source for ML/I.

C

The source language was C; i.e. the logic was compiled from the C source for ML/I.

The second letter indicates a 'major version' identifier, and the third letter changes when minor changes are made to the logic. Currently, implementations differing in only the first letter are expected to support the same features. Note that this is probably not the original scheme, but it fits with earlier versions and has now been adopted!

The table below is in chronological order, oldest version first. Many versions appear in only one or two source forms, as noted. Earlier versions did of course exist, but there is no information about them. There is also little information about some of the earlier versions mentioned below, but this is really only of academic interest. Intermediate development versions have been omitted.