Harvard architecture has separate data and instruction busses, allowing transfers to be performed simultaneously on both busses.
A von Neumann architecture has only one bus which is used for both data transfers and instruction fetches.
therefore data transfers and instruction fetches must be scheduled – they can not be performed at the same time. but It is possible to have two separate memory systems for a Harvard architecture.
Following are the difference between harvard architecture and von-neumann architecture
|Harward Architecture||Von Neumann Architecture|
|The name is originated from “Harvard Mark I” a relay based old computer.||It is named after the mathematician and early computer scientist John Von Neumann.|
|It required two memories for their instruction and data.||It required only one memory for their instruction and data.|
|Design of Harvard architecture is complicated.||Design of the von Neumann architecture is simple.|
|Harvard architecture is required separate bus for instruction and data.||Von Neumann architecture is required only one bus for instruction and data.|
|Processor can complete an instruction in one cycle||Processor needs two clock cycles to complete an instruction.|
|Easier to pipeline, so high performance can be achieve.||Low performance as compared to Harvard architecture.|
|Comparatively high cost.||It is cheaper.|