Fast help, von neuman vs harvard vs today's archiecture

[Blackhole890]

On internet says a lot and different theories...  Where should i trust? 

[Coaxialgamer]

Both of those methods describe ways the processor interacts with memory, their contents etc. 

 

-Von Neumann describes a model where both the data and instructions are stored in a central pool of memory ( read /write)  This memory is accessed via a central bus. It was thought up by the mathematician John Von Neumann, during the 50's. 

 

-Harvard actually pre dates Von Neumann, as it was actually first implemented in the Harvard Mark 1 computer of the 1940's, which used electromechanical relays. Both the data and instruction memory are kept seperate, with the former being read/write and the latter being read only. The advantage here is that both these memory pools have their own bus, thus meaning that the cpu can access data and instructions at the same time , improving performance. 

It's for this reason that modern processors use a modified Harvard architecture, wirh one of the common modifications being that both memories are read/write, allowing Von Neumann's self modifying code, among other things. You can actually see the Harvard implementation by looking at L1 cache on modern chips, which is typically split.