Streamlining Object-Oriented Software for Deeply Embedded Applications

Most of today’s computer systems are embedded and a substantial amount of them are deeply embedded systems with very limited resources. Object-oriented software is rarely to be found in those systems. In this paper we discuss reasons why currently object orientation is seldom used in this area. We also propose a set of design and implementation techniques based on modern objectoriented methods, which reconcile the reusability and flexibility of object-oriented software with the required efficiency of deeply embedded systems. 1 Introdu tion Most of today’s computer systems are more or less hidden in embedded applications like mobile phones or cars. Even some kitchen aids have their own processors. More and more application areas are “computerized”. In many if not most of them only very limited computational power is available. These so called “deeply” embedded systems are a great challenge for today’s software producers. In contrast to PCs the various constraints like cost reduction, power consumption and used memory space lead to the usage of very small processors. They are small in computational power, usually only a few MIPS, or even less. Sometimes RAM-less systems are used, but typical RAM sizes range from a few bytes to some MBytes. The software is usually hold in ROM which can take from 1 kByte to a dozen MBytes. Many of these products are hard or soft real-time systems which must respective should provide deterministic behavior regarding time. Some of the systems are even safety-critical systems e.g. avionic instruments or steering control systems in cars. Developing software which meets these constraints is not an easy task. A software architecture for this domain should provide Portability: Today available hardware changes and improves very fast. Existing software must be easily usable on new platforms. Scalability: The software should be scalable so that it is possible to provide as much or little functionality as needed for a specific application. Application software must not include “dead code”, which is never used. This work has been partly supported by the Deutsche Forschungsgemeinschaft (DFG), grant no. SCHR 603/1-1 and the Bundesministerium für Wirtschaft (BMWi), grant no. 01 MS 801/7