1.2.5. Data Processing (dp)

A DP system involves the use of a computer and related equipment for analysing and recording many facts. Data are obtained from numerous sources and are processed quickly by being converted into a code consisting of electrical impulses.

Digital computers count numbers (e.g. trip mileage on a car).

Analogue computers are used mainly in scientific research and measure physical variables, e.g. voltage or speed (e.g. the speedometer of a car).

Business processing involves the digital computer.

Figure below shows the five components of a computer. These components are:

1.Input

This consists of data to be processed and the instructions to process the data. The sequence of instruction to the computer is called the program.

Fig. 1. Data processing system. Computer installation.

The following media may be used in preparing the input from the source of data: punched cards, punched tape, magnetic disks, optical scanners, magnetic ink character readers, a console typewriter.

Punched cards and tapes are cheaper and adaptable, but are bulky, susceptible to damage and unable to hold large amounts of data, they are also slow in use. They are rarely used now.

2. Storage

This unit is often called the memory and retains input in coded form. Data are stored internally by magnetic hard disk or externally in the form of floppy disks, punched cards, paper tape, magnetic drums or tape.

3. Arithmetic unit (or processing unit)

Data are mathematically manipulated according to the program.

4. Output unit

This unit deals with results of the computing operations. The manner and position of printing are determined by the instructions.

It may be useful to have results presented in the form of a graph or dia­gram. If the computer is connected to a graphical display unit, this unit then traces the image with a spot of light on the face of a cathode-ray tube. It can also be used as a combined input system in conjunction with a device known as a light pen. An engineering drawing can be displayed on the television screen and by using the light pen the designer can make amendments or addi­tions on the screen. Another fea­ture is a graphical output which can be obtained when pen and paper move to trace out a diagram or graph.

On-line output means that the printing devices are operated directly from the computer and results are immediately available.

Off-line output refers to the results punched into cards or paper or magnetic tape. These are then placed in printing machines which are separate from the computer.

5.Control unit

A control unit interprets instructions recorded on input media, directs the var­ious processing operations and checks to see instructions are correctly carried out. This unit directs the receipt of information in the storage unit, stores the intermediate results, and releases the information when needed in the arith­metic operations.

Assignments

I. Match the following English and Ukrainian words and phrases:

digital computer	виведення інформації
analogue computer	зовнішня пам'ять
variable	уведення інформації
mileage	змінна величина
control console	цифровий комп’ютер
input	пробіг автомобіля в милях
output	пульт управління оператора комп’ютера
backing store	аналоговий комп’ютер

II. Suggest the Ukrainian equivalents of the words and phrases below:

data to be processed; the sequence of instruction; punched card; paper tape; light pen; line printer; magnetic ink character reader; console typewriter; susceptible to damage; hard/floppy disk; magnetic drum; graphical display unit; to trace the image; to make amendments; cathode-ray tube; on-line output; off-line output; to release the information; the receipt of information; input media; control unit; to trace out a diagram.

III. Find English equivalents to the following phrases from the text:

пристрій для зчитування знаків, нанесених магнітним чорнилом; дисплей для виведення графічних даних; засоби уведення інформації; оперативне виведення даних; автономне виведення інформації, світлове перо (використовується як пристрій для уведення координат і указка); магнітний барабан; діалогове виведення; автономне уведення; електронно- променева трубка; блок управління; який легко піддається пошкодженню; дискета; жорсткий диск; креслити зображення; вносити виправлення; видавати інформацію; викреслювати діаграми; друкувальний пристрій на пульті управління; перфокарта.

IV. Answer the questions:

1. What are the five components of a computer? How can information be fed into a computer and in what forms may the results be provided?

2. What is a program?

3. What are the advantages and disadvantages of punched cards and tapes?

4. What are the ways to store data?

5. What is on-line/off-line output?

6. What is the function of a control unit?