Working with Operating System

* An Operating System is a program which acts as an interface between a user and the hardware.

* The major funtions of Operating system are:

1. Program Execution
2. Handling Input/Output operations
3. Manipulation of file system
4. Error detection and handling.
5. Resources allocationv
6. Accounting
7. Information and Resource Protection

* Windows XP is a GUI based operating system. In windows operating system, multiple applications can be simultaneously run in different windows.

* In Window XP, the screen upon which icons, windows, etc. are displayed is known as dextop.

* A window is a typical rectunglar area pertaining to an application or a document or a dialog.

* An icon is a graphic symbol that represents a window element like file, folder or shortcut.

* Loading up of operating system files into the computer's memory is called booting up.

Computer Overview

* A computer is an electonic device that perform a variety of tasks according to the given instructions.
* A computer works as a data processor that processes data to form information.
* Data are raw facts that may not convey meaning.
* Information is meaningful data.
* A computer undergoes input-process-output cycle.
* Input unit carries out the input phase, CPU(Centeral Processing Unit) carries out the process phase and output unit carries out the output phase.
* The CPU consists of two components: Control Unit(CU) and Arithmetic Logic Unit(ALU). The CPU controls and supervises the task and ALU performs the arithmetic and logic operations.
* The main memory holds the data and instrutions as well as intermediate outputs during processing, After the task is performed, the output is sent to output unit and the memory is cleared.
* The unit of memory is byte. A byte consists os 8 bits and a nibble consists of4 bits. One Kilobyte(KB) is equal to 1024 bytes. One Megabyte(MB) is equal to 1024 KB. One Gigabytes is equal to 1024 MB. One Terabyte(TB) is equal to 1024 GB.