In this post we learn about the Difference between shared memory and distributed memory.

Difference Between Shared Memory and Distributed Memory

1. Distributed Memory (DM)

  • In DSM the different physical memories are logically shared over a large address space( virtual memory).
  • So the processes going on accesses the physical memory through these logically shared address space.
  • DSM have no physical shared memory.
  • The shared memory model provides a virtual address space shared between all nodes.
  • The term "shared" does not mean that there is a single centralized memory but "shared" essentially means that the address space is shared (same physical address on two processors refers to the same location in memory).

2. Shared Memory (SM)

  • In computer science, shared memory is memory that may be simultaneously accessed by multiple programs with an intent to provide communication among them or avoid redundant copies.
  • Shared memory is an efficient means of passing data between programs.
  • Depending on context, programs may run on a single processor or on multiple separate processors.
  • In computer software, shared memory is either a method of inter-process communication (IPC), i.e. a way of exchanging data between programs running at the same time.
  • One process will create an area in RAM which other processes can access; a method of conserving memory space by directing accesses to what would ordinarily be copies of a piece of data to a single instance instead, by using virtual memory mappings.