9 Conclusion

This unit started with the idea that computers have become an important part of everyday life, especially when all the ‘invisible’ computers that surround us are taken into account – those embedded in objects such as kitchen scales and digital cameras.

Three fundamental ideas introduced in this unit are:

• computers comprise both hardware (the physical objects) and software (the programs);
• computers receive data from the outside world, store it, manipulate it and present it back to the outside world;
• data in computers is represented as binary codes – that is, strings of 0s and 1s.

Figure 11 is a generic functional block diagram for a computer. This is an important diagram in the context this unit.

Figure 11: A functional block diagram of a computer which also shows the flow of data within the computer

The fundamental software components of a PC are its operating system and some application programs. Dedicated computers like those in the kitchen scales and the digital camera may well not have an operating system, but they certainly have programs to match the requirements of their applications. The tasks to be performed by these programs can be described by means of flowcharts, and you met some examples of flowcharts which describe some of the tasks performed by the three example computers of the block.

Ideas about data representation have also been applied to the three example computers, and you have seen how numbers, text, sound, pictures, analogue quantities and true/false quantities can be represented by binary codes in a computer.

You have also seen that computer instructions are represented as binary codes, and that the processor uses these binary codes to tell it what operations to perform. These operations include binary arithmetic and logic, and you have worked through some examples of both arithmetic and logic.