I was going through booting process for BIOS and UEFI where in BIOS, after first initial steps after the boot sequence, it will find bootable device where it ll get boot loader and bootloader will call boot.ini and therefor process will go like that.

But my doubt is where the boot manager comes into picture?

As per my take NTLDR will call Boot.ini, at this instance selection of os will come here but that should come under boot manager?

Can anyone clarify my misunderstanding?


The BIOS bootup is pretty straight forward. It knows which disc to boot from, then it just executes the bootloader it finds in the MBR of the specified disk - that’s it. After that the BIOS is no longer involved in booting.

Before Windows Vista:

The bootloader for Windows is NTLDR (NT-Loader) it get's his configuration from the boot.ini (this is just a text file), and with this configuration it does what it's told what to do by it... usually it starts Windows.

After Windows Vista:

NTLDR got replaced by BOOTMGR. So the MBR code will start the BOOTMGR, BOOTMGR will read the file \Boot\BCD (binary file) and show a boot menu (and checks the disk-signatur). After that (same as NTLDR) it's told what to do by it... usually it starts Windows.

  • @shivaniverma6991the update from XP to vista is the problem, it replaced NTLDR (see updated answer) – Albin Oct 17 at 19:51
  • thanks..this is what i was looking for..can you help with process of UEFI Booting process with GPT? I am not able to find proper sequence..all i can find is ESP and bootloader only.. – shivaniverma6991 Oct 17 at 20:00
  • @shivaniverma6991 sure but this is a new question, you should create a new post for it – Albin Oct 17 at 20:05
  • superuser.com/questions/1492021/… my question is already posted – shivaniverma6991 Oct 17 at 20:07
  • @shivaniverma6991 ok, I'll have a look later on. Meanwhile feel free to accept/upvote my answer (if you liked it) ;) – Albin Oct 17 at 20:08

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