Extensible, flexible and secure services in Angel, a single address space operating system

The modern operating system is caught between the rapid evolution of application requirements and the equally rapid evolution of hardware platforms. The ability for the system to adapt to meet these demands is increasingly paramount, yet the mechanisms provided, by most commercial systems, to achieve these goals are either too restrictive or too slow to be viable. Recent research work has concentrated on various solutions to this problem, usually through some form of extensible kernel, where additional services may be added as necessary. In this paper, we examine the needs of an extensible kernel in the context of Angel, a single address space operating system. We found that by sensible design of primitive kernel services, and the advantages obtained by adopting a single address space, an operating system can be made flexible, extensible and secure without compromising performance