What is windows startup process?

hello, friends it this post I will tell you about Windows startup process.When windows start then there are some steps one by windows.These steps are approximate same for Microsoft Windows all version. In this post, i will explain with help of windows XP loading process.

Windows XP,2k,2k3 operating system

1.POST
2.Initial startup process
3.boot loader phase
4.Detect and configure Hardware phase
5.Kernel loading phase
6.Login phase

Windows Vista,7 and later os

1.POST
2.Initial startup process
3.Windows boot manager phase
4.Windows boot loader phase
5.Kernel loading phase
6.Login phase

1.POST(Power ON Self Test):- As soon as we start the computer.the processor of computer follows some programming instructions.That instruction is stored in BIOS or EFI.The post is the first set of that instruction.it can diagnose and fix following problems.

A. In starting check the hardware.For example - How much memory in the system.
B. Check that device which is required for starting the computer.For example -system is having hard disk or not,
C. Get the configuration setting from volatile memory which is located on the motherboard.
This section can identify problem regarding following devices.
*floppy, Keyboard, CPU fan....

2.Initial startup phase:- There are two things in this phase.
A.Boot sequence:- computer will be booted for  This all setting are stored in BIOS. for example
Harddisk. CD drive, USB drive, Floppy drive etc.
B.Read MBR:- This detect which is the primary partition and which is the extended partition.
It can detect following problems.
*Disk boot failure.
*Error related with MBR/Partition table

3.Bootloader phase:- windows boot manager starts the boot loader phase.When user select windows7 or vista then bootloader does the following task.

A. Load the NTOSKRNL.exe, but didn't run it.
B. Load the hardware abstraction layer and does not run until the os kernel is not loaded.
C. Load the system registry in memory. (system32\config\system)
D. Scan the HKEY-LOCAL-MACHINE\SYSTEM\Securities key for device drivers And loads all drivers that are configured for booting the system। bootloader does not initiate the driver until kernel loading completed

4.Detect and configure Hardware Phase:- In this phase information collected about all connected hardware.

5.Kernel loading Phase:- In this phase, all services and drivers are loaded according to registry control settings.
hal.dll and NTOSKRNL.exe are also loaded in this phase.

6.Login Phase:- windows subsystem starts the login and logoff.
winlogon.exe files do the following task.
A.starts the services.exe.
B.starts the Local Security Authority (LSA) for administration.
C.Provide GINA (Graphical identification and authentication)
D. For authentication in Domain  Kerberos v5 Protocol and NTLM (Windows NT LAN Manager) used.

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