Mutual Exclusion

• Attacking the Mutual Exclusion Condition; Can a given resource be assigned to more than one process at once? Systems with only simultaneously shared resources cannot deadlock!
• The mutual-exclusion condition must hold for nonsharable resources (i.e., a printer).
• Shareable resources, in contrast, do not require mutually exclusive access and thus cannot be involved in a deadlock (i.e.,read-only files). A process never needs to wait for a shareable resource.
• In general, however, we cannot prevent deadlocks by denying the mutual-exclusion condition, because some resources are intrinsically nonsharable.