Abstract: A turnstile OS primitive is provided that enables support for owner tracking and waiting. The turnstile primitive enables a common framework that can be adopted across multiple different types of synchronization primitives to provide a common service for priority boosting and wait queuing. A turnstile can also provide a mechanism to enable a turnstile to block on another turnstile, allowing multi-hop priority boosting within a chain of multiple blocking turnstiles.

Abstract: A system for maintaining data consistency among distributed processors, each having its associated cache memory. A processor addresses data in its cache by specifying the virtual address. The cache will search its cells for the data associatively. Each cell has a virtual address, a real address, flags and a plurality of associated data words. If there is no hit on the virtual address supplied by the processor, a map processor supplies the equivalent real address which the cache uses to access the data from another cache if one has it, or else from real memory. When a processor writes into a data word in the cache, the cache will update all other caches that share the data before allowing the write to the local cache.