A system is a set of inter related components that work together to fulfill a purpose. For example a Road Transportation System will consist of the parts - roads, vehicles- trucks, buses, vans, cars etc, passengers, the staff for ticketing and maintenance of vehicles and roads etc. And the transportation system will fulfill the purpose of carrying of passengers and luggage from place to place. Computer system consists of the following four parts:
The mechanical devices that makeup the computer are called HARDWARE, for example, Keyboard, hard disk, monitor, processor and mother board etc. Hardware are physical devices. They can be touched. Hardware device are interconnected and perform input, processing and output operations.
Software is the set of instructions given to computer to perform a task. Software tells the computer what to do. System Software like operating systems are used to manage components and operations of computer. Application Software like MS Word and MS Excel are used to solve specific problems of the user, for example creating documents or preparing Student Result Sheet etc. Thousands of different software are available for use on PC.
Data is the collection of raw facts. Data processing is the primary job of a computer. Computer processes data in many ways to convert them into useful information. Processed data becomes information. For example, during census, data of all citizens is collected. Census data is used to get report/information about total population of a country and literacy rate etc.
People that operate the computer are called computer operators or computer users. Users use computer to solve different problems. For example, in a college a computer operator in Examination Section will feed marks obtained by students in a software like MS Excel. He/ She will perform certain functions and formulae to calculate percentage and grade of each student and prepare a result sheet. This result sheet will show the marks obtained, percentage, grade and Fail/ Pass status of every student.