Types of computers

A Mainframe
is the most powerful type of computer. It can process and store large amounts of data. It supports multiple users and more simultaneous processes at the same time. The central system is a large server which provides information and computing facilities for hundreds of terminals connected together in a network. Mainframes are used for large-scale computing purposes in banks, big companies, universities, etc.

A Desktop PC
has its own processing unit (CPU), a monitor and a keyboard. It is designed to be placed on a desk. It is used as a personal computer at home or as a workstation for group work.

A Laptop
A laptop is a portable computer that has a flat LCD screen and uses batteries for mobile use. Small laptops are also called notebooks. It can work as fast as a desktop PC, with similar processors, memory capacity. Instead a mouse they have a touchpad built into the keyboard. They offer a lot of connectivity options: USB ports, slots for memory cards, etc.

A Tablet PC
A tablet PC is a type of notebook computer that has an LCD screen on which you can write with a stylus or a digital pen. You can fold and rotate the screen easily. Your handwriting can be recognized and converted into editable text. You can also type at the detached keyboard or use speech recognition.

A PDA
A personal digital assistant (PDA) is a tiny computer which can be held in one hand. The term PDA refers to a variety of handheld devices including palmtops, and pocket PCs. For input, you type at a small keyboard or use a stylus – a special pen used with a touch screen. PDAs can be used as mobile phones, personal organizers or media players. They also let you access the internet via Wi-Fi networks, and some include a GPS navigation system.