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

3 From the Specification 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/