This is a free online Ada book “Quick Ada”.

In 1983 the language became an ANSI standard ANSI/MIL-STD-1815A. It became an ISO standard the following year. The language is defined in a reference manual often referred to as the LRM. References to this manual occur often in books on the language, and in many compiler error messages. This book is recommended for any Ada site; although hard to read it is the final authority for any Ada question (an ongoing group has been formed to clarify any inconsistancies detected in the language).

The language has since undergone revision, with ISO standardisation of the new standard achieved in early 1995. This new Ada fixes many of the flaws in the original language, and extends it in many useful ways.

To prevent the proliferation of various imcompatable versions of Ada the Ada Joint Program Office (the body set up for control of the language) took a very novel position – they trademarked the name Ada. You were not allowed to market “Ada” compilers unless they have passed a compliance test. This has subsequently been relaxed, the protected term now being `Validated Ada’.

The resulting Ada validation certificate is limited in duration and has an expiry date. Once it expires the compiler can no longer be marketed as a `Validated Ada’ compiler. In this way the AJPO has ensured that all currently marketed compilers comply with the current standards.

The aim is to ensure that any Ada program can be compiled on any system – in this regard the AJPO has succeeded better than many other language groups.