Computer system booting is the process of preparing a computer to initialize its operation. The booting checks that all hardware components are functioning well and then add the process to the operating system.
The importance of the booting process is to start and prepare the computer for the user and system use. There are 2 types of booting, cold or hard and warm or soft booting. The process of booting starts when the user clicks the power button on the system unit. Then the BIOS takes over to do the POST process. If successful it then loads the MBR to the RAM which loads the operating system to continue with the other process.
Types of computer booting
Cold or hard booting
This is also known as the hard booting process. For cold booting, the computer is powered from the wall socket where the power cable is connected. Then the user presses the power ON button to start the process. After that, the system takes over to boot the computer.
Cold booting takes more time than warm since it needs to check everything is working and load all main files to the main memory (RAM)
Warm or soft booting
It is also known as soft booting. This is the kind of booting that happens when already the computer is ON but something happens to interrupt its operation. Restarting the computer by clicking the restart command is a type of soft booting. When the computer hangs or is not responding and you restart is also another type of warm booting.
During warm booting, the process is faster than cold since the information that was in RAM is retained. Also, the speed is high since it doesn’t go through the POST process again
The function of booting in the computer. The keyboard shortcut key for computer restart is CTRL+ALT+DELETE then click on restart.
Importance of computer booting
- Check whether all computer hardware and software are functioning well.
- It loads the operating system to the main memory.
- It checks for any errors and reports back.
- It prepares the desktop and other programs for the user and system use.
Computer booting process
For a computer to boot it goes through a number of steps each met to achieve a specific objective. Below is a step-by-step procedure that a computer takes to boot.
- Power ON: this is where the user switches the socket and presses the power button on the computer to start the process.
- Power On Self-Test (POST): the computer by use of information stored on the BIOS ROM test if all computer components connected to it are in good condition. If all is OK it moves to the next step otherwise it stops the operation and gives the user an error message to do the necessary.
- Selecting booting disk: When the POST process is good, the BIOS checks for the bootable disk where the operating system is stored. Depending on the booting order that is set on the BIOS the system can boot from CD, Floppy disk, Hard disk, or Unified Extensible Firmware Interface (UEFI). UEFI is the latest type of booting that users can choose from. Users can change the booting order from the BIOS settings. CD or DVD drive is the default booting drive.
- Loading operating system to RAM: Up to this point, no data has been loaded to the main memory (RAM). After identifying the bootable disk it looks for its Master Boot Record (MBR) which is usually stored on the first sector of the disk. The MBR table is loaded first on the RAM which initiates the bootloader program. The bootloader program loads the kernel of the operating system to the RAM.
- The operating system takes over: the operating system now takes over the operation from the BIOS and continues loading all other files and programs until the user is requested to log in for security.
- Boot process complete: After entering login details the system prepares the desktop for the user by finishing loading other programs that are set to automatically load at the start. The computer is now through with the booting process and ready for use.
What are the requirements for a computer to boot?
- All critical hardware should be functioning.
- Should have a bootable drive with boot files.
- BIOS settings and files should be accessible from the CMOS ROM.
- It should have enough main memory space to store the kernel of the type of operating system the computer is using.
- Master Boot Record (MBR) table should be accessible to help in booting.