Flynn�s Classification of Parallel Architectures

On the level of systems architectures, Michael Flynn proposed a classification of parallel architectures:

� SISD (Single Instruction Single Data), in which just one stream of instructions performs a transformation on a single stream of data (this is the simplest model and corresponds to the computer architecture model described by John von Neumann.)

� SIMD (Single Instruction Multiple Data), in which the same stream of instructions is applied to disjoint sets of data

� MISD (Multiple Instruction Single Data) in which several instruction streams are applied to the same stream of data, (some sources hold that pipelined execution is the closest approximation to this approach, but we feel that this is a somewhat artificial view, since in a pipelined machine there is but one instruction stream)

� MIMD (Multiple Instruction Multiple Data), in which independent instruction streams are applied to independent sets of data (as we will see in the case of parallel DBMSs, the same program (the DBMS) is simultaneously executed, without synchronism on disjoint sets of data one speaks then of SPMD Single Program Multiple Data Stream)

Source of Information :  Elsevier Server Architectures 2005