Computer Organisation and Architecture - Stored Program Concept

What is the stored program concept?

Machine code instructions are stored in electronic memory directly accessible to the processor (main memory) which the processor fetches, decodes and then executes one at a time. Data is also stored in memory directly accessible to the processor which the processor can alter and apply arithmetic or logical operations to when needed.

Why is the stored program concept advantageous?

Any type of computation can be made without altering the hardware

What are the principles of the Von Neumann architecture?

Both data and instructions are stored in the same memory and are accessed by the same buses

Why is Von Neumann architecture advantageous?

-Simpler to design and implement the control unit as it fetches data and instructions in the same way

-Cheaper as less physical space is required

-Free data memory can be used to store instruction memory and vice versa so can use memory efficiently.

Where is the Von Neumann architecture used?

General purpose computers

What are the principles of the Harvard architecture?

Data and instructions are stored in different memories and are accessed by different buses

Why is Harvard architecture advantageous?

-Both data and instructions can be accessed simultaneously to reduce bottlenecking in buses and delays in fetching from memory

-Allows the data and instruction memories to be implemented differently

-Harder for hackers to exploit and inject code

Where is the Harvard architecture used?

Where the processor only has to do one major task such as in embedded systems or in digital signal processing (DSP) systems