Operating Systems: Concurrent and Distributed Software Design

A.4. Concurrency control

A.4.1. Mutual exclusion without hardware support

Section 10.2 discussed how processes can achieve mutually exclusive access to shared data. There we emphasized the use of hardware support in the form of composite instructions and discussed the option of forbidding interrupts inside the kernel of a uniprocessor. Nowadays composite instructions are provided and can be used for the lowest level of concurrency control. But in the early days of computer systems, hardware was restricted in its scope and concurrency control had to be achieved without composite instructions.

A great deal of research effort was directed towards the mutual exclusion problem before processor designers routinely provided instructions on which mutual ...