Parallel computers can be classified in at least four ways:
Single Instruction stream Single Data stream (SISD)
Single Instruction stream Multiple Data stream (SIMD)
Multiple Instruction stream Single Data stream (MISD)
Multiple Instruction stream Multiple Data stream (MIMD)
These classifications are discussed in more detail in the Appendix:
Michael J. Flynn proposed this classification in 1966, and it is still in use today. The Cray-1 and the CDC 7600 supercomputer discussed in the following sections are of the SISD class. Use the following link to learn more about Flynn: https://en.wikipedia.org/wiki/Flynn's_taxonomy.