Incremental Growth by Threads

A vertical functionality growth by processes in micro kernel-based operating systems leads to ineffective solutions due to the growing communication overhead. Properly speaking, the system designer has to deal with the trade-off between the flexibility ensured by the finegrained operating system modules and the effectiveness, requiring application-tailored and monolithic services. In order to handle this problems we propose a Dynamic Configuration Facility (DCF) representing a light-weight server process for run-time specification and binding of threads. DCF provides incremental growth of the operating system modules at two levels: (1) by threads providing a low cost shared memory communication and (2) by processes providing a high degree of encapsulation and parallelism. Additionally, the DCF allows one and the same module to be implemented as a thread or as a process, so that a runtime varying of the implementation strategy is possible. To provide this a C-language- oriented tool specifies the thread interface in form of movable “remote” data structures, so that the thread environment could be considered as a framework of stubs, where typed threads could be bind in run-time.