Chapter 2 - Data Manipulation (the CPU)

General Outcomes

• Apply understanding of a CPU's instruction set and the instruction cycle to various scenarios, e.g.,
  • Read a set of instructions and understand the results.
  • Respond to potential student questions about computer operation.
  • Decide which elements of computer operation are useful for student understanding and which can remain at the level of magic.


• Identify hardware components of a computer and describe their relationship and interaction. (The idea is to be able to respond reasonably to student questions such as "What is a ________ in a computer and what does it do?)


• Explain the process whereby a computer's CPU can be connected to or communicate with a variety of external (peripheral) devices and indicating any limits on the type or number of such devices.


• Apply an understanding of computer memory/storage to a variety of situations in both CS classroom and daily life, e.g., [This section comes from chapter 1]
  • Provide a rationale for choosing amounts of various kinds of memory when purchasing a computer based on speed and cost considerations.
  • Explain primary uses for various kinds of memory and the impact of speed and persistence/permanence.


• Analyze (identify salient aspects of) broader concepts/issues with respect to computer architecture in our society, e.g.,
  • Development of substantially more power computer systems such as quantum computing and brain-inspired computers. What might be their impact? What role should the government plan in guiding or controlling their development and use?
  • General knowledge. Students study reading, writing, mathematics, and (to a lesser extent) science. Should computer science be included as a basic of education? If so, should that study include the inner workings of computers?
  • Should we be worried that some computer manufacturer might build a chip that could spy on the user of any device using the chip?

Learning Objectives

By the end of this unit students should be able to:

• Define the purpose of the [ ALU | Control Unit | registers | program counter | instruction register] and the role it plays in the CPU.
  • Talk through Figure 2.1
• Explain how general-purpose registers, main memory, and secondary memory (mass storage) work together and their role in fetching/storing data.
  • As part of this, explain the differences between mass storage, main memory, and general-purpose registers.
• Identify and/or explain the following vocabulary related to Mass Storage
  • Magnetic Storage
    • magnetic disks (aka HDD)
    • track
    • cylinder
    • seek time
    • rotational delay
    • transfer rate
  • Optical Storage (aka, Compact Disks, DVDs, and Blue-ray)
  • Flash Storage (aka, Flash drives, Solid State Drives (SSD), SD cards)
• Explain why we still have three broad classes of secondary/mass storage
• Consider which media type is more appropriate for a particular scenario
• Given the language description table (Appendix C in the textbook) and a single VOLE command, convert the command into English.
• Given the language description table and an English description of a computer operation, produce the corresponding VOLE command.
• Given a partial description of memory/registers and a single VOLE command, identify the value of a particular register or memory cell upon completion of the command.
• Given a listing of multiple, sequential, memory addresses, containing a valid program written in the VOLE machine language, trace the execution of the program to answer questions about the status of the machine upon completion of the program.
• Explain the role of a controller in the operation of a computer.
• Explain the role of a port in the operation of a computer.
• Identify at least three ports common to a [PC | mobile device]