We can classify computer architectures into two categories:
von Neumann architecture: computers has a single, common memory space in which both program instructions and data are stored. There is a single internal data bus that fetches both instructions and data. They can not be performed at
the same time
Harvard architecture: computers have separate memory areas for program instructions and data. There are two or more internal data buses, which allow simultaneous access to both instructions and data. The CPU fetches program instructions on the program memory bus.
