Input device

For a desktop computer, you typically use a keyboard and mouse to enter data. However, because using a mouse takes up room, other devices are built into laptops to take its place. Laptops come with one of three input devices that allow you to move the cursor on the LCD screen

• trackball - rotating the ball allows you to move the cursor on the LCD screen (usually built-in, but add-on ones that clip to the side of a laptop are available).

• trackpoint - pushing your finger over the point moves the cursor;

• touchpad - moving your linger across the pad moves the cursor. All of these devices have buttons that act like the right and left buttons on a mouse

The type of device you want is purely a matter of preference. Some people prefer the feci of a trackball over a touchpad. If you can try out various input devices to see what feels right to you. Remember, most laptops have a port that allows vou to hook up a mouse to your laptop, but again, that will be another device to carry around if you want to use it on the go.

KEYBOARD Because space is a premium for laptops, their keyboards tend to be smaller than desktop keyboards. Although you won't find an ergonomic keyboard, like the Microsoft natural keyboard, on a laptop, most laptop keyboards have some ereonomic features, such as being located at the back half of the unit to provide wrist support. The arrow keys will most likely be in different places to conserve space, and you may not have a numeric keypad. If you can, try out several laptops to see if, the keyboard feel comfortable; this is especially important for touch typists.

MODERN COMPUTERS II

And who has not heard about computer-aided design, or computer-assisted process control and fault diagnosis, or computer-based learning, or, lastly, computer games which are extremely captivating not for children only but for adults as well? Thus, at its simplest, the computer can be defined as a programmable electronic device that can store, retrieve and process information (data). The word programmable here means that computer's operation is based on a program - a specially arranged list of instructions. Every computer incorporates hardware and software The former includes machinery and devices, the latter - all computer systems and programs. According to the purpose the following classification of computers may be suggested

MODERN COMPUTERS I

Originally computers were supposed to perform calculations. This accounts for the origin of the word itself coming from the Latin word computo which means to count. The development of electronic computation, however, has resulted in the tact that modern computers are used extensively in various fields of human activities, not for calculations only; and these fields are becoming more and more diverse. Now you can hardly imagine an accountant's desk without a computer, to say nothing of a research laboratory. Modern computers can solve a great variety of tasks: to perform mathematical calculations, to help researchers in their investigations, to help doctors in making diagnoses, to store large volumes of information, etc

MODERN COMPUTERS III

Information can and does take any forms. You can see these different forms every time you use your computer. The words you are reading right now the signals from the keys you press on your keyboard, the files you load on your hard disk - all are different types of information that your computer manipulates. Depending on the way the information is represented in a computer, the latter can be either analog or digital or hybrid. There are two ways to represent information. Information that is continuous, that is, any piece of information can take on any of an infinite set of values, is said to be analog.

Mainframe computers

Mainframe computers have more memory, speed, and capabilities than workstations and are usually shared by multiple users through a series of interconnected computers They are large, extremely fast, multi-user computers that often contain complex arrays of processors, each designed to perform a specific function. Mainframes control businesses and industrial facilities and are used for scientific research. The most powerful mainframe computers also called supercomputers are the fastest class of computers. Their speed and power are almost beyond human comprehension. Supercomputers process complex and time-consuming calculations, such as those used to create weather predictions. They attain these speeds through the use of several advanced engineering techniques. Because these computers can cost millions of dollars, they are used mostly by government, large businesses, scientific institutions and the military.