Single Instruction and Single Data stream (SISD)

In this organisation, sequential implementation of instructions is executed by one CPU having a single processing element (PE), i.e., ALU beneath one control unit as given away in figure 4. Therefore, SISD machines are conventional serial computers that procedure only one stream of data and one stream of instructions. This type of computer organisation is depicted in the figure:

                                                                                      Is = Ds = 1

Some Examples of SISD machines contains:

• CDC 6600 which is unpipelined but has many functional units.
• CDC 7600 which have pipelined arithmetic unit.
• Cray-1 which supports vector processing.
• Amdhal 470/6 which have pipelined instruction processing.