Implementation and Evaluation of a Dynamically Reconfigurable Operating System Server with Dynamic Protection

摘要

In this paper, we implement and evaluate a dynamically reconfigurable operating system server with dynamic protection. The server is an application program running on a base operating system. The server we consider in this paper is; (i) the server consists of a small kernel and server tasks, (ii) the operating system server and user tasks run in a single virtual address space supported by the base operating system, and (iii) the virtual address space consists of two kind of spaces, called kernel space for the kernel and user space for the server tasks and user tasks, which spaces are statically protected. By extending this operating system server, this paper implements a dynamically reconfigurable operating system server with dynamic protection which supports; (i) dynamic injection (removing) of the server tasks into (from) the kernel space, (ii) dynamic adding, injection, removing, and exchanging of new functions, and (iii) dynamic exchanging of a kernel scheduler. The results of performance evaluation show; (i) the dynamic injection of the server tasks improves system performance, (ii) the dy- namic protection is relatively large, and (iii) the dynamic exchanging of the kernel scheduler provides well-suited environments for user tasks.