Every time you sit down to use your computer you more than likely will have to wait for it to "boot up". So why does this process have to happen every time you press the power button and why is it essential to your computer's operating system? Most of us acting as simple computer users cannot appreciate the complex functions that are happening behind the scenes so to speak.
Booting up? I'm sure at some point you've wondered to yourself why would the process of starting your computer be referred to as booting up? This phrase refers to the age old idiom of "pulling yourself up by your bootstraps." In other words, the computer cannot run without first running software but the computer must be running before any software can be installed. Now this makes sense! You can read more about this here. http://en.wikipedia.org/wiki/Booting
You may recognize the screenshot above to be similar to what you see when starting up your computer. So exactly what is happening and how does the computer get going?
BIOS in ROM
When you press the power button on your computer the power supply turns on and allows the processor to start. The processor is pre-programmed from the manufacturer such as Intel or AMD to look in a specific place in ROM memory to find instructions on where to find the entire BIOS or basic input/output system startup program. The BIOS performs the power on self test or POST and if any errors are found the system will beep. If no errors are found the BIOS will search for the video card's built in BIOS program which initializes the card and allows the screen to display information. The BIOS then looks for the hard disk program to initialize. After this the startup screen as shown above is displayed to the user. The computer then checks for any errors and goes through a checklist to ensure that all computer components have been initialized. Then the BIOS searches the hard disk for a master boot record which is what actually starts the computer's operating system. When this record is located the operating system's code takes over and properly loads the OS. If no master record can be found on the hard drive the screen will display a message saying there is "no boot device available". This message may alarm you and it should! More than likely this means there is something wrong internally with your hard disk. I hope you remembered to back up your data! But hopefully you didn't receive this message and your computer is ready to use.
Hopefully you can now understand a little better what is going on behind the scenes inside your computer the next time you press the power button.
Hopefully you can now understand a little better what is going on behind the scenes inside your computer the next time you press the power button.
