what is Booting Process in computer?

The Booting (booting up) is bootstrapping process that start operating system when the users terns onto the computer system. A boot sequence is a set of the operation the computer performs when it switched on to load  a operating system.

Most of the computer can only execute code found in the memory (ROM or RAM ). Modern Operating system are stored on hard disk, or occasionally on LiveCDs , USB flash drives , or other non volatile  storage device . When a computer is first powered on, it doesn't have an operating system in memory. The computer hardware alone cannot perform complex operation(ex loading a program from disk) , so an apparent paradox exists : to load the operating system already loaded .

The solution is to use a special small program , called bootstrap loader , bootstrap loader . This program is only job to load  other software for the operating system to start . Often ,multiple -stage boot loader are used  , in which several program of increasing complexity summon each other , until the last of them loads the operating system.

In modern computer the bootstrapping process begin with CPU executing software contained in ROM (for example  the BIOS of an IBM pc) at predefined address (the CPU designed to execute this software after without outside help). This software contains rudimentary functionality to search for device eligible to participate in booting process , and loaded a small program from special from a special section (most commonly the boot sector ) of the most promising device can be booted from and or/and to give priority to some devices over others (A CD or DVD drive is usually given priority over hard disk , for instance).

The Boot Process is considers complete when the computer is ready to interact with the user or the operating system is capable to running ordinary application . Typical modern PCs boot about a minute (of which about 15 sec are taken by a power -on self test POST preliminary boot loader , and the rest by loading the operating system ), while large server take several time to boot and to start all service.

Usually Computer start with instruction as above . However , at time you may find that computer start randomly or sometimes your computer hang and you need to restart deliberately . There are two ways to rebooting called cold and warm booting.

A Cold reboot (also know as a hard reboot , cold reboot or cold start) is when power to a computer is cycled (turned off and then on) or a special reset signal to the processor is triggered . This restart the computer without performing any shut-down procedure , it may be caused of power failure ,be done by accident, or be done deliberately.

Now there are a number of operating system and most modern PCs offer than users to work on two operating system on a single system . for instance , you can install both the window and linux on your PC and can work simultaneously . When the computer start it show you on a screen of choice to start with operating system you need at that the point of time .