INTRODUCTION

Overview

This paper will present a study of practical design decisions relevant to the retargeting of a traditional compilation system to a distributed target environment. The knowledge was gathered during the course of Honeywell's Distributed Ada project which involved the retargeting of a full commercial Ada compilation system to a distributed environment. The goal of the project was to create a compilation system which would allow a single unmodified Ada program to be fragmented and executed in a distributed environment.

The Distributed Ada Project

The trend in embedded system architectures is shifting from uniprocessor systems to networks of multiple computers. Advances in software tools and methodologies have not kept pace with advances in using distributed system architectures. In current practice, the tools designed for developing software on uniprocessor systems are used even when the target hardware is distributed. Typically, the application developer factors the hardware configuration into software design very early in the development process and writes a separate program for each processor in the system. In this way, software design gets burdened with hardware information that is unrelated to the application functionality. The paradigm is also weak in that no compiler sees the entire application. Because of this, the semantics of remote operations are likely to be different from local operations and the type checking that the compiler provides is defeated for inter-processor operations.