DEVELOPING RECONFIGURABLE DISTRIBUTED HARD REAL-TIME CONTROL SYSTEMS IN STER

Abstract

This paper presents the approach of the STER system to develop architecture independent real-time software. STER clearly separates the development of the basic software components (modules) and the configuration of applications (systems). In STER, the timing constraints of modules are specified at the configuration level, making reusable software modules able to meet the timing requirements of different applications. A distributed program in STER is constructed using four levels of abstraction, represented by the entities module, group, station and system. Modules can share resources using special modules called servers. To meet the timing and resource constraints of modules, STER adopts a scheduling strategy in three levels: 1) off-line scheduling of Hard Real-Time (HRT) modules, 2) dynamic time driven scheduling of Soft Real-Time (SRT) modules and 3) dynamic time sharing scheduling of Non Real-Time (NRT) modules.