4. The oldest tool used by man for calculating was the ABACUS The first computer invented by Konrad Zuse in 1939 was called “Z1” In 1944 an IBM engineer created a calculator which was the half of a football field In the middle of the 1940ies, VonNeumann gave the computer, the capability to be more versatile Thanks to the invention of integrated circuits it was possible to miniaturize computers

5. hardware software computer

6. HARDWARE is everything that the concerns the physical part of the computer like the keyboard, the monitor or the central unit. the Keyboard, the monitor, the mouse and the printer are called PERIPHERALS

7. The SOFTWARE includes everything you can’t touch that is inside the computer, for example its programs. The Software is divided into 2 categories: the operating system and the application program. The first allows the communication between man and machine

8. computers are divided into 4 main categories: -Supercomputers -Mainframes-Minicomputers-Home computers Supercomputers are the most powerful, the fastest and the most expensive kinds of computers. They Are used mainly in research centers, in meteorological and molecular fields The mainframe has a powerful processor and a very huge RAM. mainframes are used a lot (by many people at the same time), each of which uses a terminal that is connected to the mainframe itself. They are expensive and used by big companies, banks and airports The minicomputers are smaller than the earlier ones but still able to handle large amounts of data in many situations. The minicomputers are smaller than the earlier ones but still able to handle large amounts of data in many situations. Personal computers, used by a single user to work in the office or at home. These are divided into DESKTOP COMPUTERS and LAPTOPS