Types of Computer Systems Words and word-combinations necessary to comprehend the text:

Simulating tsunami impact –імітуючи вплив цунамі;

nuclear explosion - ядерний вибух;

multi user system - система, з якою можуть одночасно працювати декілька користувачів;

large-scale computing purposes - для дуже масштабних обчислень;

battery packs - комплект батарей;

electrical outlets - електричні розетки;

connectivity options - можливості під єднання;

peripherals - периферійні пристрої, пристрої які під'єднуються до комп'ютера;

detached keyboard - від'єднана клавіатура;

voice recognition - розпізнавання голосу;

a tablet - записна книжка;

hand-held - кишеньковий;

palmtop - мініатюрний комп'ютер (див.handheld);

wireless technology - бездротова технологія

Computers in present use range considerably: from tiny things to very big ones. A super-computer is a computer that is among the largest, fastest and most powerful of the computers available. The fastest supercomputer of late 2007 performs trillions operations per second. And they are being improved all the time. Soon they will be able to perform one quadrillion operations per second. Supercomputers are used to solve problems that are very complex or problems that deal with incredibly small or incredibly big things or things which are dangerous to deal with. Here're some examples:

Climate research; Studying of the Sun and space weather; Simulating of tsunami impact; Modeling nuclear explosions; Different medical testing.

A mainframe is not so powerful as a supercomputer but it is used for large-scale Computing purposes in banks, big companies and universities. It can process and store large amount of data. It is a multi user system i.e. it can be used by many people at the same time. It is also a multi-tasker - can support many simultaneous processes more than a PC. The central system is a large server connected to hundreds of terminals over a network.

A desktop PC used as a personal computer in the home or as a workstation for group work is the most common type of a computer. Typical examples are the IBM PC and the Apple Macintosh. It has its own processing unit (or CPU), monitor and keyboard. Some models have a vertical case called a tower. It is designed to be placed on the desk. A laptop (also called a notebook PC) is a lightweight computer that can be easily carried and is the most popular type of portables. It can work as fast as a desktop PC with similar memory capacity but it has a smaller screen. Instead of a mouse, it has a touchpad built into a keyboard - a sensitive pad that you can touch to move the pointer on the screen. It comes with battery packs, which let you use the computer when there are no electrical outlets available.

They offer a lot of connectivity options: USB (Universal Serial Bus) ports for connecting peripherals, slots for memory cards, etc. A tablet PC looks like a book, with LCD screen on which you can write using a special digital pen. You can fold and rotate the screen 180 degrees. You can also type at the detached keyboard or use the voice recognition. It's mobile and versatile. A personal digital assistant or PDA is a tiny computer which can be held in one hand. The term PDA refers to a wide variety of hand-held devices, palmtops and pocket PCs. For input you type at a small keyboard or use a stylus - a special pen used with a touch screen to select items, draw pictures, etc. They can be used as mobile phones or as personal organizers for storing notes, reminders and addresses. They also let you access the Internet via wireless technology, without cables.