Ada 95 and Safety-critical Software

The revised Ada standard (ISO/IEC-8652:1995, commonly referred to as Ada 95) was released by the International Standards Organization (ISO) in February 1995. One of the unique features of this standard is that it is divided into a Core Language, which must be fully implemented, and several Specialized Needs Annexes, which provide standard definitions for additional features for particular application areas. Of particular interest to developers of safety-critical software is Annex H: Safety and Security. This Annex specifies detailed documentation requirements and facilities to support enhanced understanding of program execution paths and for reviewing object code. It also provides facilities for restricting the use of certain language constructs. This paper will discuss Annex H and will also present the charter of the recently formed Annex H Rapporteur Group.