nightlight

Hai friends.

I think all my frinds of Ld knows what is booting.But some people maybe don't know what is the booting process actually and what is the process happens behind while booting.so friends here i am trying to explain waht is the booting.

Here i tried to explain the process of booting what I know.


The Windows XP boot process consists of the following steps:

1. The system is powered up, the video is initialized, and the hardware self-tests are
performed. The BIOS performs these tests, which are called POSTs (power-on selftests).
Usually, the memory test is the most visible one; its progress is shown on most
computer screens.

2. After running POST, the system initializes each adapter. If the adapter has its own
built-in BIOS, the adapter's BIOS is called to perform its own initialization. For IDE
adapters (most computers have either two or four IDE adapters), each connected drive
(there may be up to two drives for each IDE adapter, allowing for a total maximum of
eight IDE type drives) is queried for its specifications and access method.
Some adapters, such as Adaptec's SCSI adapters, display messages and allow the user
to interact. Some adapters that don't have a BIOS aren't initialized until Windows XP
loads their drivers much later in the boot-up process.

3. After all the adapters that have a BIOS have been initialized, the system boot loader
reads in the sector located at the very beginning of the first bootable disk drive and
passes commands to this code. This sector is called the boot sector, or the MBR
(Master Boot Record), and it is written by the operating system when the operating
system is installed.

4. The code in the MBR then loads the NTLDR file. (This file has no extension, though
it is an executable file.) Once loaded, the MBR passes control to the code in NTLDR.

5. NTLDR then switches into 32-bit mode. (Remember, an Intel x86 processor always
boots into 16-bit real mode.) It then loads a special copy of the necessary file system
I/O files and reads in the file boot.ini.

6. The file boot.ini has information about each operating system that can be loaded.
Remember, Windows XP supports multiboot configurations. It is trivial to create a
Windows XP installation that can boot Windows NT, Windows XP, and Windows 95
or Windows 98. The boot loader can even boot two different copies of Windows XP
with either the same or different version numbers. NTLDR then processes boot.ini,
displaying boot information that allows the user to select which operating system will
be loaded. At this point, let's assume that Windows XP will be loaded.

7. When you select Windows XP to be loaded, NTLDR loads the file ntdetect.com. This
program then collects information about the currently installed hardware and saves
this information for the registry. Most of this information is stored in the
HKEY_LOCAL_MACHINE hive.

8. Once NTDETECT has detected the hardware, control is passed back to NTLDR, and
the boot process continues. At this point, the registry has been substantially updated
with the current hardware configuration, which is stored in
HKEY_LOCAL_MACHINE\Hardware.

9. The prompt to select the configuration is then presented. This prompt, "Press spacebar
now to invoke Hardware Profile/Last Known Good menu," allows you to force
Windows XP to use a specific configuration as stored in the registry hive
HKEY_LOCAL_MACHINE.

10. Following the detection of NTDETECT, NTLDR loads and initializes the Windows
NT kernel, loads the services, and then starts Windows.

11. When the kernel is loaded, the HAL is also loaded. (The HAL—Hardware Abstraction
Layer—is used to manage hardware services.) Next, the registry system subkey
HKEY_LOCAL_MACHINE\_System is loaded into memory. Windows XP scans the
registry for all drivers with a start value of zero. This includes those drivers that
should be loaded and initialized at boot time.

12. You can see the beginning of the next stage, kernel initialization. The screen switches
to a blue background, and you see a message about the Windows XP build number
and the number of system processors. Again, the system scans the registry and finds
all drivers that must be started at the kernel initialization stage.

13. From this point, Windows XP starts various components and systems. Each
component and system reads the registry and performs various tasks and functions. In
the final stage, the program that manages the user logon, WinLogon, starts. WinLogon
allows the user to log on and use Windows XP.


Pl reply so that i can share more stuff like this with u all

harsha29

nice info nightu..

msusheel317

thank u

pari_earth

booting ku intha pedda tatangam untadani nenu anukoledu hmm so nitu good post keep posting

Mac

THANK you nighyyyyy..... but maa Macs ki registry vundathu... so vaati meeda kooda oks post cheyi

tanu

good post, nice, keep posting like this.

Dreamer

wow nice info brother i know only 60% of that info .. rest all was new to me thanks for sharing

surajsarve

Good info. for the post

user_02

Good info, keep posting

kitsee

hatsoff for ua post mate