Ada 95 and software reuse

Lockheed Martin Tactical Aircraft Systems and Texas Instruments recompiled over 2 million non-comment non-blank source lines of code (SLOC) in the avionics and vehicle management services subdomains, originally written in Ada 83, using four Ada 95 compilers. Two avionics applications were linked and executed using a workstation-based simulator to verify gross functionality. A Distributed Systems Annex (DSA) version of this code was created and executed successfully on multiple workstations across a TCP/IP network. Translating Ada 83 code to Ada 95 compatibility proceeded much faster than expected, about 2000 lines per hour, and was easily accomplished with only a text editor. Once translated, the code proved highly portable between compilers. The greatest challenge was not in Ada version incompatibilities, but in assumptions inherent in the legacy code. Ada 95 compilers will require at least 6 go 12 months of maturation to be capable of supporting a large avionics development effort. Particular weaknesses in is the lack of task-aware pre-processors for handling multiple aircraft configurations from a common source code base, and support for optional language annexes. However, the Ada 95 tools resolve major problem areas of Ada 83 tools, including compilation order dependencies and lack of object-oriented features, and in general compile much faster. When mature, these Ada 95 tools are expected to provide significant productivity gains over their Ada 83 counterparts.