YEAR 1 CO1 WEEK 6 COMPUTER ARCHITECTURES Flashcards
State the key features of Von Neumann Architecture
One control unit (to read/write)
One instruction executed at one time.
Program data stored in same memory.
Used same bus for data and instructions.
Used fetch decode execute cycle.
State issues with Von Neumann Architecture.
Data Corruption as instructions/ program stored in same memory unit as data there is a risk of instructions being overwritten so program wouldn’t work anymore.
Von Neumann Bottleneck where as data bus speed slower than the CPU’s processing speed it is often left constantly waiting for something to do as it waits for data to be fetched.
Fetch Rates where data and instruction may have to be fetched at different rates which is difficult as they share the same data bus.
Memory Leaks where a well written program automatically removes memory it is finished using with otherwise it fills up leaving little for current program to access.
State features of Harvard Architecture.
Data and instruction stored in separate memory units.
Each have their own complete set of buses they use.
In theory less chance of bottlenecks and data corruption.
State the benefits of Harvard Architecture.
Units of different sizes can make more efficient use of available memory.
Different word lengths for different memory units.
State Issues of Harvard Architecture.
Physical space where more components needed such as memory and buses.
Complexity where more complicated for CPU to co-ordinate.
