• Architectures

Question 1

What is the stored program concept/ von nuemann architecture defined as?

Answer 1

Machine code instructions are fetched and executed serially by a processor that performs arithmetic and logical operations.

Question 2

What are requirements of the stored program concept?

Answer 2

• A program must be resident in main memory to be executed.

* The machine code instructions are fetched from memory one at a time, decoded and executed in the processor.

Question 3

How are instructions and data stored in the the von neumann machine?

Answer 3

• Instructions are data are stored in a common main memory and transferred using a single shared bus.
• The same data bus is used to transfer both data and instructions
• A single address bus is used to transfer the addresses of data and instructions.
• The same word length is used for all memory, whether it holds data or instructions.

Question 4

Ho ware busses utilised in the von nuemann machine?

Answer 4

• The same data bus is used to transfer both data and instructions
• A single address bus is used to transfer the addresses of data and instructions.
• The same word length is used for all memory, whether it holds data or instructions.

Question 5

What is the Harvard architecture?

Answer 5

A computer architecture with physically separate memories for instructions and data.

Question 6

How is the storage of programs and data in Harvard architecture different to Von Neumann

Answer 6

• Data and instructions are separated into separate memories, using different busses.
• Program instructions and data are no longer competing for for the same bus.

Question 7

What is an advantage of Harvard over Von Nuemann architecture, in terms of data & instruction retrieval?

Answer 7

• Harvard architecture can be faster, this is because data and instructions can be fetched in parallel instead of competing for the same bus.
• One bus for data and instructions is a bottleneck in Von Nuemann

Question 8

How does the uses of von nuemann architecture compare to Harvard architecture?

Answer 8

• Von Neumann
  • Used in conventional processors in PCs, servers and embedded systems with only control functions
• Harvard
  • Used in digital signal processing, embedded systems, mobile communication systems, audio, speech and image processing systems.

Question 9

How do programs & data compare between Harvard & Von Neumann Architecture?

Answer 9

• Von Neumann
  • Data and programs share the same memory
• Harvard
  • Instructions and data re held in separate memories

Question 10

How do busses compare between Von Nuemann & Harvard?

Answer 10

• Von Neumann
  • One bus is used to transfer data and instructions
• Harvard
  • Parallel data and instruction busses may be used.

Question 11

How does the size of programs compare between Von Nuemann & Harvard?

Answer 11

• Von Nuemann
  • Programs can be optimised in size
• Harvard
  • Programs tend to be large

Question 12

What are some advantages of Von Neumann Architecture?

Answer 12

• Cheaper
• Simplifies design of the control unit
• Data from memory and from devices are accessed in the same way.