An introduction to the FDE cycle - questions and answers
Q1. Does the CPU fetch instructions from RAM or the hard drive?
A1. RAM.
Q2. What does RAM stand for?
A2. Random Access Memory.
Q3. What stage follows the Fetch stage in the FDE cycle?
A3. Decode.
Q4. What piece of information does the Program Counter hold?
A4. The address of the next instruction to be fetched.
Q5. What is the purpose of the Accumulator?
A5. This holds the data being worked on and the results of arithmetic and logical operations.
Q6. Explain why having more cache usually speeds up processing.
A6. Cache is closer the CPU and uses faster solid state technology than RAM.
Q7. How many instructions can a CPU work on at any one time?
A7. One.
Q8. What is the purpose of the control unit?
A8. This part of the CPU is responsible for managing how instructions are executed. It has some very important jobs to do! It is in charge of fetching instructions and data from wherever they are stored in the memory unit. It does this by sending control signals at the right time to various parts of the computer that then access the correct memory unit location and retrieve the contents of that location. Its next very important job is to interpret, or 'decode', an instruction so that it knows what has to be done. It has a special piece of equipment called an 'instruction decoder' to do this.
Q9. What are the characteristics of a Von Neumann processor?
A9. a) Uses a single processor. b) Uses one memory for both instructions and data. c) Executes programs by doing one instruction after the next in a serial manner using a fetch-decode-execute cycle.
Q10. Give one simple example of an arithmetic question and one simple example of a logic question.
A10. Arithmetic question: 3 + 4 and a logic question is 010011 AND 011101