Just Give Me the Beans!
How does Grub "call on" Windows during boot on a dual boot PC?
This is not in any way an "urgent" question or anything like that, just something I'm a bit curious about: when I boot up Windows on my dual boot PC (Windows 7 to be precise), what exactly happens at the moment when Grub "hands over responsibilities" to Windows?
Just Give Me the Beans!
The best technical info I could find on the GRUB chainload process is on this page: https://wiki.osdev.org/I_use_a_Custo...ight_for_me%3F
After that, you'd have to ask someone about Windows itself.For Windows, a record is placed which indicates the partition Windows is installed on, and an instruction to chainload one sector (512 bytes) into RAM at 0x7C00, and jump to it; In other words, simply load the Windows bootloader into RAM as if it was placed there by the BIOS.
Last edited by freemedia2018; February 15th, 2019 at 12:27 PM.
Just Give Me the Beans!
Thank you!Originally Posted by freemedia2018
Super Master Roaster
Some more info on the Windows boot process.
http://thestarman.pcministry.com/asm/mbr/VistaVBR.htm
http://thestarman.pcministry.com/asm...7MBR.htm#INTRO
http://www.multibooters.co.uk/multiboot.html
http://www.multibooters.com/guides/v...-sequence.html
Grub only boots working Windows, and the load of Windows PBR from grub seems to be faster than BIOS MBR to PBR, so barely enough time to press f8 to get into Windows repair console.
Best then to always have Window repair flash drive for current version of Windows.
UEFI boot install & repair info - Regularly Updated :
https://ubuntuforums.org/showthread.php?t=2147295
Please use Thread Tools above first post to change to [Solved] when/if answered completely.
Just Give Me the Beans!
Thank you!
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