Separating Protection and Resource Management in Operating Systems

Traditionally, operating systems have fulfilled the dual roles of enforcing security on computer systems, as well as managing and virtualizing resources for the various applications sharing the machine. However, more recently, there have been some promising proposals in creating systems where hardware, rather than software enforces security and protection. These proposals would require an operating system running on such hardware to manage resources on behalf of applications that do not trust it. Unfortunately, the implementation of such an operating system has not received much attention in the literature and it is not clear if a traditional services of an operating system could be provided on such hardware. This paper discusses the modifications that are necessary to make a modern operating system execute on such hardware. The modifications were modest, the most significant changes were in the areas that perform context switches, signal handling, and virtual memory management.