Suppose I take a digital photograph of myself for my website. Horrified by my wrinkled, baggy appearance, what can I do? Actually, with the right software I can do more or less anything I like: I can smooth out the wrinkles; I can restore the grey hair to its former splendour; I can even put in a background of books to give me a scholarly appearance. In fact, I can so improve the picture that if you met the real me you probably wouldn't recognise me.
‘Massaging’ my photographic image may seem a trivial reason for using a computer to acquire features of reality, but actually it has enormous significance. Figure 1 shows a landscape in which it may be difficult to distinguish what is real from what has been added by the computer. I say a bit more about this in Subsection 2.5.1, but a proper discussion will have to wait
For each of the purposes above (storage, control, exchange, and manipulation), try to think of a specific example in which a computer is used for such a reason.
There is a huge range of examples you might have come up with. Here are just a few suggestions.
Storage and presentation
keeping copies of all your letters or digital films;
keeping records of all the books in a library.
control programs in a washing machine;
traffic control systems in large towns.
battlefield command and control systems;
exchange of data and command between ground control and distant space probes;
any computer network.
computer-aided design systems;
garden planning and design systems.