Bootstrapping

The process of initializing the computer and loading the operating system is known as bootstrapping. This usually occurs when the computer is powered-up or reset.
The initial loading is done by a small program that usually resides in non-volatile memory (e.g., EPROM). This in turn loads the OS from an external device.
Once loaded, how does the operating system know what to do next? It waits for some event to occur: e.g., the user typing a command on the keyboard.
During ``normal'' operations of a computer system, some portions of the operating system remain in main memory to provide services for critical operations, such as dispatching, interrupt handling, or managing (critical) resources.
These portions of the OS are collectively called the kernel.

Kernel = OS - transient components
remains comes and goes

$\includegraphics[scale=0.5]{figures/bootstrapping1.ps}$	$\includegraphics[scale=0.5]{figures/bootstrapping2.ps}$
$\includegraphics[scale=0.5]{figures/bootstrapping3.ps}$	$\includegraphics[scale=0.5]{figures/bootstrapping4.ps}$
$\includegraphics[scale=0.5]{figures/bootstrapping5.ps}$

**Figure 6:** UNIN System initilization
$\includegraphics[scale=1]{figures/unixsysteminit.ps}$

Cem Ozdogan 2004-03-13