The Boot Process

In this lesson, we're going to learn  
 how our operating system starts up.  
 As an IT support specialist,  
 you'll probably work on lots  
 of computers that won't start.  
 It's important to know the steps  
 and operating system takes,  
 so you can help diagnose the issue.  
 Booting a computer or starting a computer comes from  
 the phrase to pull oneself up by one's bootstraps.  
 Basically, it means to start from nothing and follow  
 a series of steps to  
 arrive at a fully operational system.  
 When we start up with computer,  
 will use the term boot.  
 For most operating systems,  
 the boot process follows a general pattern,  
 much like how we have different cars  
 startup in the same way.  
 Put in the key, turn on the ignition, etc.  
 Here's a rundown of the boot process.  
 First, the computer is powered on.  
 The BIOS/UEFI is a low-level software that  
 initializes our computer's hardware  
 to make sure everything is good to go.  
 Next, the bios UEFI runs a process called the  
 power-on self-test, or post.  
 The post performs a series of diagnostic tests to  
 make sure that the computer is in proper working order.  
 Next, depending on the bios or  
 UEFI configuration of boot device will be selected.  
 Devices that are attached to  
 our system, like hard drives,  
 USB drives, CD drives,  
 etc, are configured in a certain boot order.  
 The devices will be checked in this order and  
 the computer will search for  
 what's known as a bootloader.  
 The bootloader is a small program  
 that loads the operating system.  
 Once our computer finds  
 a bootloader on a device in the listed order,  
 it will start to execute this program.  
 This will then start to load  
 a larger and more complex program  
 and eventually loads our operating system.  
 Once the bootloader loads up our operating system,  
 our kernel gets loaded.  
 The kernel controls access to our computer's resources.  
 It also loads up drivers and more so  
 that our hardware can talk to our software.  
 Next, essential system  
 processes and user space items are launched.  
 These include processes like user login,  
 spinning up a desktop environment,  
 and more which basically  
 allows us to interact with our system.  
 And that's it. After these simple steps,  
 you'll be able to get to work. 
 
 
 
 
 
 
 
 
 
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