Brief description
This module examines what a computer is and how it works, down to a level just above electronics. It considers how a program, written in a high-level language, is ultimately executed by a computer.

Aims
This module provides students who intend to study software development with an appropriate initial understanding of the hardware on which programs run and how programs are executed.

Learning outcomes
On successful completion of this module, student will be able to:

• draw a block diagram of a computer and explain how it works;
• explain what machine codes are and how they are executed by a CPU;
• describe how a computer performs input and output operations;
• explain how abstract concepts in high-level languages, such as function call or local variable, are implemented in machine code.

Syllabus
1. What is a computer? - 2 Lectures
Block diagram overview; CPU, memory, I/O, Bus. Memory; pigeon-hole model, address and contents, bits bytes and words.

2. Buses - 1 Lecture
Address, data and control buses. Basic data transfer.

3. The concept of a stored machine instruction - 2 Lectures
Simple examples of instructions. The fetch-execute cycle and the program counter.

4. Inside the CPU - 4 Lectures
Registers. ALU. Control unit. Implementing a machine code in hardware. Digital logic.

5. A real CPU example: Motorola 68000 and 68HC11 - 3 Lectures
Some machine codes and mnemonics. Addressing modes. Assembly code.

6. Executing high-level software - 4 Lectures
Machine-code equivalents of high-level constructs. Function calls. Stack frames and local variables.

7. I/O - 5 Lectures
Reading and writing data. Interrupts. Transfering large amounts of data; DMA, block I/O.

8. Exercises - 4 Practicals
Use a CPU simulator to watch instruction execution. Assembly language comprehension (probably, but not necessarily, by writing a program).