For GNAT People

[grt <grt@pisa.intecs.it>]

The GUARDS project is an Esprit activity of the European Community. 

It is intended to define the most suitable development environment for
hard real-time dependable software applications such as railway,
spacecraft and nuclear installation control.  

The involved partners are:
Technicatome, 
Matra Marconi Space, 
LAAS-CNRS, 
University of York,
Siemens AG Osterreich PSE, 
Ansaldo Trasporti, 
Intecs Sistemi (my company)
Pisa Dependable Computing Centre. 

I am currently involved in the selection of the design method, 
the related tool, the final implementation language.  

In the last years greater and greater importance has been attributed
to the non-functional requirements, in particular to the deadlines
associated to time requirements. If such requirements are not faced
very early in the software life-cycle, then the reliability of the
developed system might be hardly affected.  Techniques have been then
developed to be able to check that the deadlines are met even in the
worst case of execution.  Tools that apply such techniques are called
Schedulability Analyser.  They need a description of the system
dynamic behavior and the execution time of pieces of sequential code.
After the development phase it is easy to measure the required times,
but we would like to be able to perform the analysis BEFORE all code
is produced and without exercising the specific hardware.  At this
purpose it is needed a so called Worst Case Execution Time
Analyser. It is a tool able to estimate with a high degree of
confidence the execution time given the source code statements. My
company's role includes the development of such a tool.

Being GNAT one of the candidate Compilation System I am interested to
know your opininion about the level of support we can have from the
compiler: the basic idea is to have dis-assembled the selected piece
of code (it is still TBD how to select it) and analyse the assembly
code taking into account the CPU cycles for each statement. 
More, the final target for application is still TBD, but it will be an
industrial 32 bit board with a POSIX-like executive: 
what about Ada95 and C++ using GNU software?  
In particular for C++, does exist a validated factory in such
environment ?

Sandro Paganone

e-mail: sandro@pisa.intecs.it