Primary Memory and the MIC Topic 2.1.2 / Core
Key points
  • the difference between random access memory (RAM) and read-only memory (ROM);
  • their use in primary memory;
  • the use of cache memory and its effect in speeding up the system;
  • the machine instruction cycle;
  • the role of data bus and address bus.
  • random access memory (RAM);
  • read-only memory (ROM);
  • cache memory;
  • the machine instruction cycle;
  • data bus;
  • address bus.
  • Computer Confluence chapter 0 Basics
  • Computer Confluence chapter 1 Computer Currents and Internet Waves
Related topics


Look at the Art of Science web site. The relevant image here is the one of Mona Lisa.

  1. Work through this presentation on primary memory and the machine instruction cycle..
  2. Research typical sizes and prices for RAM. How much does your laptop have and how much would it cost to double it?
  3. Read Computer Confluence, The Computer's Memory p. 89 to 90.
  4. State two differences between RAM and ROM. [2 marks] (May 2009 SL P1 q1)
  5. With the use of an example, explain the term volatile when used to describe computer memory. [2 marks] (November 2008 SL P1 q8)
  6. (a) Explain the function of cache memory. [3 marks]
    (b) Outline the need for virtual memory. [3 marks] (November 2007 SL P1 q6)
  7. Define virtual memory and give an example of when it might be used. [2 marks] (May 2006 SL P1 q9).
  8. Outline the four steps in the machine instruction cycle. [4 marks] (May 2008 SL P1 q4).
  9. Describe the role of buses in the machine instruction cycle. [4 marks] (May 2006 SL P1 q2)