In many years, computer architecture has gone through evolutional instead of revolution changes supporting features are those that were demonstrated execution delivers.
According to the figure we initiated with the Von Neumann architecture developed as a sequential machine implementing scalar information. Sequential devices enhanced from bit serial to word-parallel operations & from fixed point to floating-point operations. The Von Neumann architecture is moderate because of the sequential implementation of instructions in the program.
Look ahead, Parallelism, and Pipelining − Lookahead methods were initiating to prefetch instructions to overlap I/E (instruction fetch/decode and execution) operations and to allow functional parallelism.
Functional parallelism was provided by two methods such as first is to use multiple functional units together and the other is to process pipelining at multiple processing levels.
The recent grasp pipelined instruction execution pipelined arithmetic computations and memory connection operations. Pipelining has tested particularly attractive in executing identical operations continuously over vector data strings. Vectors operations wQues123ere initially carried out essentially by software-controlled looping using scalar pipeline processors.
Flynn’s Classification − Michael Flynn (1972) established the nomenclature of a mixture of computer architectures located on the theory of instruction and data streams.
Traditional sequential machines are SISD (single instruction stream over a single data stream). Vector computers are set with scalar and vector hardware or emerge as SIMD (single instruction stream over multiple data streams). Parallel computers are called MIMD (multiple instruction streams over multiple data streams) machines.