Guidance for the use of the Ada programming language in high integrity systems

Abstract

This paper is the current result of a study by the ISO HRG Rapporteur group which is being circulated for comment. Many people have contributed to this, but those who have either attended two recent meetings of group or have made substantial e-mail comments are: Praful V Bhansali (Boeing, USA), Alan Burns (University of York, UK), Bernard Carre' (Praxis Critical Systems, UK), Dan Craigen (ORA, Canada), Nick Johnson MoD, UK), Stephen Michell (Canada), Gilles Motet (DGEI/INSA, France), George Romanski (AONIX, USA), Mark Saaltink (ORA, Canada), Gareth Rowlands (MoD, UK), Adam Tacy (MoD, UK), (Phil) JP Thornley (BAe, UK), David Tombs (DERA, UK), Tullio Vardanega (ESA/ESTEC, Netherlands), Brian Wichmann (NPL, UK).

An ASIS-based static analysis tool for high-integrity systems

“…The results of this Phase I research indicates that, using the operations specified in the ASIS interface, it is feasible to automatically check Ada 95 source code against the majority of the proposed HRG guidelines [6]. Specifically, as shown in Table 1, it is possible to detect 49 out of 53 restrictions using ASIS.…”

“…The study analyzes every feature of Ada 95 and provides recommendations for their use in safetycritical applications. An update to the original report was recently completed by the HRG and circulated for comments [6].…”

Diversely designed classes for use by multiple tasks

“…This offers more flexibility and allows us to better utilise system resources. Thirdly, it is well known that it is often difficult to formalise and to properly use dynamic task creation, as well as to analyse systems which dynamically create tasks [16]. To answer all the concerns above, the DD object and, in particular, the controller should be able to allow N tasks to issue N replicated calls of any of its methods.…”

Kernel Ada to unify hardware and software design

“…In addition, the Ada community that creates high integrity systems [1,10] has restricted similar constructs. These efforts define informal subsets (although the term is rarely used); standard Ada compilers are used with either pragmas or tools to restrict features that are considered potentially dangerous.…”