Thursday, March 4, 2010   Did you ever wondered what actually
happens between the time we power on our PC to the time a login
prompt is displayed? This time is the so called “booting
process”or “bootstrapping”. You might have heard of that term
before but here we are going to see in details what actually
happens during bootstrapping.  Before we start with the booting
process it is necessary to understand a few terms. The first of
them is Real and Protected mode of the CPU. Early computers(
Intel 8086) with 20 bit addresses where able to access only 1MB
(2^20) of physical RAM. They used Intel's segmented memory
addressing with 16-bit registers where each register can by
itself refer to just 64KB of memory. The 20-bit memory address
can be accessed only by using a segment register and offset
register together . This is called real mode segmented memory
model with only 1MB of addressable memory. With 32-bit CPU's
(starting Intel's 80386) memory address became 32-bit (total of
4GB of memory) long and the register