BOOTING A COMPUTER
Booting/bootstrapping is the process of starting or resetting a computer, which involves loading an operating system into memory (RAM).
There are two methods of booting a computer. They include:
- Cold booting: This is the initial process of turning on a computer after it has been powered off completely. Also called Hard boot.
- Warm booting: This is also called soft boot, a warm boot is one method of resetting a computer system that is already powered on.
A warm boot can be accomplished by pressing the CTRL – ALT – DEL keys simultaneously, or by selecting the restart command from an operating system menu. Warm boots run faster than turning a computer off and on again.
CIRCUMSTANCE THAT MAY REQUIRE RESTARTING A COMPUTER (WARM/SOFT)
- When an application or operating system freezes/hangs/ does not respond
- After installation of a new software (application or utility)
- When a peripheral or hardware component has failed to function/work
- During/After installation of operating system.
- After changing use control settings(CMOS/BIOS settings)
- When a user wants to clear a malicious infection like malware, spyware, viruses that are in memory
- After software update
- After uninstalling software
- After uninstalling hardware
- After installing a new hardware
- When the computer system slows down
- When there is suspected system tapping
- When a user wishes to switch from one operating system to another (Multiple O.S)
- After malware/virus scanning
- When a deadlock occurs
- Before Installing software
- When application software fails to work
REASONS TO EXPLAIN WHY COMPUTERS ARE WARM BOOT
- To refreshes the system.
- To flush RAM and removes other files that could be causing computer freezing Clears memory off any malware.
- To increase the processing speed and system performance. Reboots are known to keep computers running quickly.
- To stop Memory Leaks which occur when programs don’t close properly.
• Completing the installations by allowing the system to configure or initiate a new software or hardware
- Fixes Internet/network Connection. Sometimes computers lose their connection to the Internet or network and need restart to re-establish the connection
WINDOWS BOOTING PROCESS
- If all the cables are well connected, turn on the wall switch that sends the power to the power supply unit.
- The power supply sends and electrical signal to the motherboard and other devices located in the system unit.
- The CPU resets itself and looks for the ROM that contains the BIOS.
- The BIOS executes the Power-On Self – Test (POST) to make sure that the computer hardware is connected properly and operating correctly.
- The results of the POST are compared with data in a CMOS chip on the motherboard.
- If the POST is completed successfully, the BIOS looks for the boot program that loads the operating system.
- Once located, the boot program is loaded into memory and executed, which then loads the kernel of the operating system into RAM.
- The operating system loads system configuration information, and the remainder of the operating system is loaded into RAM, and the desktop and the icons display on the screen.
POST is an in-built program that checks whether certain hardware is available and is working properly. It happens at boot up and checks; CPU, RAM, CMOS, video card, HDD and HDD controllers, mouse, keyboard etc.
- Errors found are returned in form beeps Non fatal errors are errors displayed on screen and the computer can complete boot up Fatal errors are errors that don’t allow the computer to complete e.g. failed/absence of RAM
What is the kernel
The kernel is the core or the heart of the operating system that preforms all management functions of the OS. The kernel is memory resident- its is a running program/process for as long as the computer is on.
Roles of the kernel
- Does process scheduling
- Manages virtual memory
- Manages user privileges
- Allows processes to communicate
Conclusion on booting
- Booting/bootstrapping is starting the operating system.
- Booting/bootstrapping is loading the operating system into memory.
- The boot loader is the program for booting.
- The boot sector of the hard disk contains code for booting.
- A master boot record (MBR) is a special type of boot sector at the very beginning of partitioned computer HDD.
These links explain more about booting in computers
THIS VIDEO EXPLAINS MORE ABOUT COMPUTER BOOTING