The incorporation of multi-level IPC into Unix

Abstract

The author discusses the design, interface, and implementation issues that need to be addressed for Unix to support multilevel synchronized file access, pipes (FIFOs), messages, and semaphores. It is shown that, by changing some of Unix's underlying mechanisms and by making additions to system calls and the run-time library, it is possible architecturally to support more flexible sharing and communication. This increased sharing simplifies the building of multilevel applications, both trusted and untrusted, to run on top of Unix.<>