A-level Computing 2009/AQA/Computer Components, The Stored Program Concept and the Internet/Machine Level Architecture

Internal and External Hardware Components of a Computer
 * Outline the basic internal components of a computer system. (Although questions about specific machines will not be asked it might be useful to base this section on the machines used at the centre.
 * Understand the need for and means of connection between components
 * Processor, main memory, address bus, data bus, control bus, I/O controllers and I/O ports, secondary storage, their purpose and how they relate.
 * Know that the processor, system bus and main memory are called the CPU (central processing unit), and that components external to the CPU are called peripherals. An example of a peripheral is secondary storage.

Functional Characteristics of a Processor
 * Understand the concept of addressable memory.
 * Describe the stored program concept whereby machine code instructions stored in main memory are fetched and executed serially by a processor that performs arithmetic and logical operations

Structure and Role of the Processor
 * Understand the characteristics of contemporary processors
 * Explain the role and operation of a processor and its major components.
 * Explain the effect of clock speed, word length and bus width on performance.

Know the following components and be able to describe their function:
 * Arithmetic Logic Unit
 * Control Unit
 * Clock
 * General purpose and dedicated registers


 * Hardware and software
 * /Internal and external hardware components of a computer/
 * /Functional characteristics of a processor/
 * /Structure and role of the processor/
 * /Machine code and processor instruction set/
 * /The Fetch–Execute cycle and the role of registers within it/