Seema Sirpal Delhi University Computer Centre
What is a Computer?
An electronic device that stores, retrieves, and processes data, and can be programmed with instructions. A computer is composed of hardware and software, and can exist in a variety of sizes and configurations.
Hardware & Software
The term hardware refers to the physical components of your computer such as the system unit, mouse, keyboard, monitor etc.
The software is the instructions that makes the computer work. Software is held either on your computers hard disk, CD-ROM, DVD or on a diskette (floppy disk) and is loaded (i.e. copied) from the disk into the computers RAM (Random Access Memory), as and when required.
Types of Computers
Mini and Mainframe Computers Very powerful, used by large organisations such an banks to control the entire business operation. Very expensive! Personal Computers Cheap and easy to use. Often used as stand-alone computers or in a network. May be connected to large mainframe computers within big companies.
Hardware Components
Input Devices -- "How to tell it what to do“ - A keyboard and mouse are the standard way to interact with the computer. Other devices include joysticks and game pads used primarily for games. Output Devices -- "How it shows you what it is doing" - The monitor (the screen) is how the computer sends information back to you. A printer is also an output device.
Hardware Components
INPUT DEVICES The Mouse Used to ‘drive’ Microsoft Windows The Keyboard The keyboard is still the commonest way of entering information into a computer Tracker Balls an alternative to the traditional mouse and often used by graphic designers
Hardware Components
INPUT DEVICES Scanners A scanner allows you to scan printed material and convert it into a file format that may be used within the PC Touch Pads A device that lays on the desktop and responds to pressure Light Pens Used to allow users to point to areas on a screen