- A COMPUTER IS A FAST CALCULATING DEVICE IT IS ALSO KNOWN AS A DATA PROCESSOR BECAUSE IT CAN STORE PROCESS AND RETRIEVE DATA WHENEVER DESIRED
- THE ACTIVITY OF PROCESSING DATA USING A COMPUTER IS CALLED DATA PROCESSING DATA IS RAW MATERIAL USED AS INPUT TO DATA PROCESSING AND INFORMATION IS PROCESSED DATA OBTAINED AS OUTPUT OF DATA PROCESSING
- KEY CHARACTERISTICS OF COMPUTERS ARE AUTOMATIC SPEED ACCURACY DILIGENCE VERSATILITY MEMORY LACK OF INTELLIGENCE AND LACK OF FEELINGS
- CHARLES BABBAGE IS CONSIDERED THE FATHER OF MODERN DIGITAL PROGRAMMABLE COMPUTERS
- SOME OF THE WELL KNOWN EARLY COMPUTERS ARE MARK I (1937-44), ABC (1939-42), ENIAC (1943-46), E D V A C (1946-52) E D S A C ( 1947-49) U N I V A C I (1951), IBM-701 (1952), AND IBM-650 (1953)
- DR. JOHN VON Neumann introduced the “stored program concept that considerably influenced the development of modern digital computers due to this feature we often refer to modern digital computers as stored program digital computers
- “Generation” in computer talk provides a framework for the growth of computer industry based on key technologies developed originally it was used to distinguish between hardware technologies but was later extended to include both hardware and software technologies
- till date there are five computer generations-first second third fourth and fifth
- figure 1.5 summarizes the key hardware and software technologies and key characteristics of computers of five computer generations
- all computer systems perform the following five basic functions for converting raw input data into useful information- inputting storing processing outputting and controlling.
- figure 2.1 shows the main components of a computer system
- input unit enables feeding of data and instructions to a computer system from outside world in computer acceptable form
- input interfaces transform input data and instructions (fed to a computer through its input devices) into binary codes that are acceptable to the computer
- output unit enables a computer system to supply information (obtained from data processing ) to outside world in human acceptable ( readable) form
- output interfaces transform information (obtained form data processing) from binary form to human acceptable (readable) form
- storage unit of a computer system holds data and instructions to be processed and intermediate and output results of processing two types of storage are primary and secondary storage as compared to primary storage secondary storage is slower in operation larger in capacity cheaper in price and can retain information even when computer system switches off or resets.
- during data processing actual execution of instructions takes place in the arithmetic logic unit (ALU) of a computer system
- control unit (CU) of a computer system manages and coordinates the operations of all other components of the computer system
- control unit and arithmetic logic unit of a computer system together form the central processing unit (CPU) which serves as the brain of the computer system and is responsible for controlling the operations of all other units of the system
- we often refer to a computer as a computer system because it consists of integrated components ( input because it consists of integrated components ( input unit, output unit storage unit and CPU) that work together to perform the steps called for in a program
