In-class work: OS Organization

This lecture will provide an introduction to operating system organizations, monolythic, microkernel, etc. Please read the assigned paper, which describes the exokernel organization. The JOS operating system you are building in the labs is organized like an exokernel.

Answer the following question: In lab 4 you completed building the core of an exokernel-based operating system. In class you studied xv6, a monolithic operating systems. Both are intended to support the UNIX API, but their internal organizations are different. A good example is the virtual memory implementation: JOS implements many virtual-memory-related functions (such as fork) in its library operating system, while xv6 implements them in the kernel. Give an concrete example of what a user program could do in JOS that a user-level program on xv6 is unable to do and why it is useful.