Are there any drawbacks in using computers?

Are there any drawbacks in using computers?

Computers can replace people

There is no doubt that the use of computers has lead to unemployment.

Computers hold personal information which may be misused

It is very easy to misuse the personal information held about individuals on computers. This will be looked at more closely in Chapter18.

Problems arise when computers cannot be used

Sometimes a computer system breaks down so things have to be done manually or postponed until it is fixed.

Staff needs to be trained

Training can be expensive and if the staff leaves new staff will need to be trained.

Processing data

Computers are used to process data. What we mean by ‘processing’ is doing something to the data. Processing includes:

· Calculating – for example working out how much pay an employee gets

· Sorting – your teacher may require a class list arranged in alphabetical order

· Searching – your head teacher may want to produce a list of all pupils who stay for school dinners

· Storing – Information may be stored on the computer instead of using a paper-based system; old letters or memos may never be needed again but it might still be worth keeping them for a few years.

· Drawing – you might use a paint package in your art lesson or a computer aided design (CAD) package in your technology lesson to design a product.

The central Processing unit (CPU)

The central processing unit (often called the CPU or simply the processing unit) processes the raw data and turns it into information. We need not look too deeply into how it works because, as you can imagine, it is quite complicated. If you ever need to open up the case of a microcomputer you will see that there is a series of circuit boards containing the main processor along will various memory chips.

You will also find a transformer and sometimes a fan which is responsible for the hum that you get from a computer. Chips give out quite a bit of heat during operation, so a fan is used to cool them down.

There are three main elements of the central processing unit:

o The control unit, responsible for coordinating the input and output devices

o The arithmetic and logic unit in which all the calculations and logical decisions are made

o The immediate access store, which provides immediate memory for holding data and programs.

The immediate access store (IAS) is on a chip or a series of chips inside the computer. Data held here can be accessed immediately, unlike data held on disk, which can take some time to load.

Figure 2.6 shows how these three main parts of a computer are arranged. In this diagram the solid lines are the data signals passing between the various sections or units. The dotted lines show the signals that are used to control the peripheral devise.

Figure 2.6: Central Processing unit with peripherals

Processing units for large mainframe computers look like metal cabinets. Smaller microcomputers, as shown in Figure 2.7, come in a variety of types, such a desktop notebook and palm top computers.

The two types of signal

There are two kinds of signals that pass between the main processor and the other hardware. These are:

· Control signals-these include signals sent out by the main processor to the printer to tell it to be ready to receive some data.

· Data signals-these are the groups of binary digits that are used to represent characters (letters of the alphabet, numbers, punctuation marks, etc.)

A. Desktop