Shared memory refers to a (typically) large block of Random access memory that can be accessed by several different central processing units (CPUs) in a multiple-processor computer system. The problem with shared memory systems is that the many CPUs need fast access to memory and will likely cache memory. Whenever one cache is updated with information that may be used by other processors, it needs to immediately update the shared memory, otherwise the different processors will be working with different data (see cache coherence and memory coherence). This article needs to be cleaned up to conform to a higher standard of quality. ... This article needs to be cleaned up to conform to a higher standard of quality. ... Multiprocessing is traditionally known as the use of multiple concurrent processes in a system as opposed to a single process at any one instant. ... In computer science, a cache (pronounced kăsh) is a collection of data duplicating original values stored elsewhere or computed earlier, where the original data are expensive (usually in terms of access time) to fetch or compute relative to reading the cache. ... Cache coherency (alternatively cache coherence or cache consistency) refers to the integrity of data stored in local caches of a shared resource. ... Memory coherence (also cache coherence or cache consistency) is the property of the shared memory systems (multiprocessors and distributed shared memory systems) in which any shared piece of memory (cache line or memory page) gives consistent values with accordance to earlier agreed consistency model despite accesses (maybe parallel) from different...

The alternatives to shared memory are distributed memory and distributed shared memory, with another, similar set of problems. Distributed memory is a concept used in parallel computing. ... Distributed Shared Memory (DSM), in computer science, refers to a wide class of software and hardware implementations, in which each node of a cluster has access to a large shared memory in addition to each nodes limited non-shared private memory. ...

Appendage

In software the term shared memory refers to memory that is accessible by more than one process, where a process is a running instance of a program. In this context, shared memory is used to facilitate interprocess communication. See the entry for thread (computer science) for more information about processes and threads. A thread in computer science is short for a thread of execution or a sequence of instructions. ...