Operating Systems: Concurrent and Distributed Software Design

4.14. Sequential programs with system calls

We have seen how a single process, supported by the operating system, is used to execute a single user-level application. This model is assumed in the discussion on language systems presented in Section 4.13. Each user-level process is typically independent of all others and needs only interact with the operating system (by means of system calls). Section 4.4 showed how the operating system allows a process to synchronize with the hardware by means of a WAIT primitive and event signalling. This interaction with the hardware is typically done by an operating system process (that is, a process executing operating system code) acting in response to a request by a user process. In a concurrent system it ...