What is computer ? A device that computes, especially a programmable electronic machine that performs high-speed mathematical or logical operations or that assembles, stores, correlates, or otherwise processes information. One who computes. It’s a Programmable machine that can store, retrieve, and process data. Today's computers have at least one CPU that performs most calculations and includes a main memory, a control unit, and an arithmetic logic unit.
Charles Babbage (1791-1871) THE FATHER OF COMPUTER
Generations of computer Computer can classified in to five types according to generations i.e time period . First generation computer . Second generation computer . Third generation computer . Fourth generation computer . Fifth generation computer
. First generation computer Period :1945 – 1956 Inviter :Lee de Forest Main processing device :Vacuum tubes
. First generation computer Advantages : . It was only electronic device . First device to hold memory Disadvantages : . Too bulky i.e large in size . Vacuum tubes burn frequently . They were producing heat . Maintenance problems
. Second generation computer Period :1956 – 1963 Inviter :William Shockley Main processing device :Transistor Storage media : Magnetic disc
1 2 Transistor
. Second generation computer Advantages : . Size reduced considerably . The very fast . Very much reliable Disadvantages : . They over heated quickly . Maintenance problems
. Third generation computer Period :1964 – 1971 Inviter :Jack Kilby Robert Noyce Main processing device :IC (integrated circuit) Storage media : Floppies
. Third generation computer Advantages : . ICs are very small in size . Improved performance . Production cost cheap Disadvantages : . ICs are sophisticated
. Fourth generation computer Period :1971– present Inviter :Ted Hoff Main processing device :ICs with VLSI (Very Large Scale Integration) Storage media : Floppies, CDs.
ICs with VLSI (Very Large Scale Integration)
. Fourth generation computer Advantages : . It is a compact . Less power consumption . Production cost is cheap Disadvantages : . No artificial intelligent.
. Fifth generation computer Period :present and beyond Main processing device :ICs with parallel processing Storage media : Video disks Advantages : . Artificial intelligence . Expert system
. First generation computer . Second generation computer Vacuum tubes Transistors . Third generation computer . Fourth generation computer ICs ICs with VLSI . Fifth generation computer ICs with parallel processing
Characteristics of a computer Computer is a group of electronic devices used to process the data. The characteristics of a computer are: 4. Accuracy 5. Automation 6. Functionality 7. Tirelessness 1. Speed 2. Reliability 3. Memory capacity
Speed: computer process the data at an unimaginable speed. The speed of the computer ranges up to Nano seconds. • 2.Reliability: The next important characteristic of a computer is its reliability. we can always rely on the information given by a computer. • 3. Memory capacity: The memory capacity of a computer is measured in bits and bytes. Large amount of the data can be stored in computer and retrieved. Memory capacity of the computer ranges in Giga bytes.
4. Accuracy: Accuracy of the computer is very high it performs calculation with greater accuracy in less time. 5. Automation: A computer allows automation for any process designed in the form of a program. A program can be executed any number of times to repeat the process.
6. functionality: computer can performs many kinds of jobs. It not only process the data but also can be Used for playing music, movies, and printing jobs. It finds its applications in all most all the fields. 7. Tirelessness: A computer never get tired.