Method and apparatus for crash safe enforcement of mutually exclusive access to shared resources in a multitasking computer system

摘要

A fast crash safe method and apparatus for enforcing mutually exclusive access to shared resources in a computer system through the use of semaphores. The acquisition and release of the semaphores is implemented at the user process level. An overestimate and underestimate of semaphore ownership are maintained in memory by library provided semaphore acquisition and release code. A cleanup routine reconciles the overestimate and underestimate to determine the ownership status of the semaphores. <IMAGE>