What is System Boot in OS?
For the system to boot properly, it is necessary that all its hardware devices are working properly. System boot is an action that each processing unit has to perform first.
If the BIOS and hardware used in the processing unit are working properly, it boots up and the operating system begins to load into memory.
Booting is basically the process of starting the computer. When the CPU is turned on for the first time, there is nothing inside the memory.
To start the computer, load the operating system into the main memory, and then the computer is ready to take commands from the users.
When the power switch of the processing unit is turned on, first of all, the motherboard gives power to the CPU so that it can diagnose (evaluate) other hardware.
It then instructs the ROM BIOS to execute the 1855 startup program stored under it. So that it can start the booting process accordingly.
The programs stored under ROM BIOS first perform the function of POST (Power On Self Test). After this, a program called 'boot loader' is executed, whose task is to load the operating system and other similar system software.
The work of POST is done in about 10 seconds but the interval at the time of loading of the operating system can be calculated based on the hardware configuration of the system. Generally, it is about 1 minute in the GUI operating system.
Operating system loading (Booting Process):
On turning on the computer, its permanent memory RAM 3 BIOS (Basic Input Output System) IC first checks all the devices, this process is called POST (Power on Self Test).
After this, the operating system present on the disk is stored in RAM (memory) as well as the main file of MS-DOS is executed.
These files are as follows:- command.com, IO.sys, ms-dos.sys, config.sys, himen.sys etc. Finally ms dos prompt appears on the computer screen or Windows opens. In this way, the OS automatically stored in memory in the computer is called "Booting.
The disk in which booting commnd.com, IO.sys, and ms-dos.sys files are stored is called booting disk.
Types of Booting in OS :
There are following two types of System Booing
- Cold Booting
- Warm or Hot Booting
1. Cold Booting:
As its name suggests, cold booting means stick booting, it is also known as soft booting. When the computer starts up for the first time or is in a shut-down state and switches on the power button to turn on the system, this type of process of starting the computer is called cold booting.
Its time is higher than warm booting as it restarts all the tasks. During cold booting, the system will read all the instructions from the ROM (BIOS) and the operating system will automatically load into the system.
2. Warm Booting:
This booting process is also known as the hot booting process, this process starts when we restart the computer in ON mode, the warm booting process turns on the computer system in a very short time.
The warm or hot booting process occurs when computer systems enter an unresponsive or hang state, and then the system is allowed to restart during the condition.
A warm boot is also called a soft boot. It refers to when we restart the computer. Here, the computer does not start from the initial state.
When the system hangs sometimes it needs to be restarted when it is on. Therefore, in this case, warm boot occurs. Restart or CTRL+ALT+DELETE keyboard buttons are used for warm boot.
Steps of Booting
We can divide the process of booting into 6 steps -
1. The Startup:
This is the first phase in which the current flow works on all the devices, processors, BIOS, Motherboard, etc. of the computer, when the computer starts, it is in this phase.
This step is a power-on reset, which verifies all of the computer's basic hardware components and their configuration before moving on to the next steps.
2. BIOS: Power On Self Test:
After power on, the booting process enters this phase, in this step, it checks whether all the devices of the Basic Input/Output System (BIOS) are working properly or not. This is an initial test performed by the BIOS.
Furthermore, this test performs an initial check on the input/output devices, main memory of the computer, disk drives, etc. Also, if an error occurs, the system produces a beep sound.
3. Loading Operating System:
In this step, the bootable operating system is loaded by creating separate drives in the main memory with the help of a pen drive or CD-ROM. The operating system starts working and executes all the initial files and instructions.
4. System Configuration:
System configuration defines the computer hardware, processes as well as the various devices that comprise the entire system and its boundaries. In this phase, the drivers are loaded into the main memory. Drivers are programs that help in the functioning of peripheral devices (Keyboard, Monitor, etc.).
5. Loading System Utilities:
In this step the work of booting is almost over, here system utilities like a system driver, volume controller, antivirus, graphics, etc. are loaded into the main memory.
6. User Authentication:
In this step boot checks whether the user has set the password in his computer system or not, if the password is not set then the process of booting is complete and the computer system is fully on.
And if the user password is set, then the password is checked, if the password matches, then the system finally starts, if the password does not match, the process of booting stops there. This password is stored in memory while creating it.
In this way, the process of booting is completed step by step.
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