Can anyone explain the boot up procedure

[modobo]

Please can anyone explain the boot up procedure for Win 10, 8 and 7. I do not think they are the same. Im also trying to find out why when I choose a flavour of Windows from the boot up menu, instead of the computer to go straight to the selected Windows it restarts the computer.

[Geek-9pm]

How much detail do you need?
what is the objective?
How much do you already know?

The low-level code of Windows is not published.  So it might be a violation of the Microsoft license if I, or anybody,  gave you the annotated source code.

Linux is open source. You can study well documented files.Of course if is not the same as windows. The full source code of Linux is available.

Before going further, please respond to my questions. That can help me and others here provide the best answer. 

Meanwhile, here is a link about how Windows XP does boot up.
http://www.tomshardware.com/forum/79335-45-explain-boot-process
Look it over, no quick answer was given. 

[modobo]

Thanks for your response Geek-9pm. I dont know anything about the start up procedure of  Win 7 8 10, Im old school, I only know BIOS and Dos stuff. The computer Im working on does not use old BIOS, I think its UEFI they call it now.

The objective is to design my own boot up code and put it on usb. I dont like the way Windows have done theirs. When I choose  say Win 7 from the boot up menu on selected drive, instead of it to go to Win 7, it restarts and goes back to UEFI, I dont like that.

On my computer I have been using the uEFI  boot manager to choose the drive that I want. I got 5 independent drives with different partitions and diff os.  On one of the drives with 7 and 8 I got win 10. So what happens is win 10 just wont play ball even if set as the default OS. If I last logged out of win 10 then the next time I put on the pc and select that particular drive, I would not get a windows boot menu, it will simply go straight to win 10. Though it goes to my account and I log in, the desktop would not be my desk top or where I left off. I have to restart and go through the bios boot manager again, choose the drive again and sometimes I have to repeat this 4 times before I get a windows boot manager for that particular drive. Only after going through the windows boot manager and choosing win 10 would I see my own desktop.  There is only one account on that win 10, no other. I dont know what is causing this or where the ghost desktop is coming from.

Anyway I don't want to bore you will all the other issues Im facing on my setup but I feel that if I can make a usb boot drive then the boot up menu for all the partitions can be programmed onto it.  The problem I am facing is that if it were dos, I could have used something like EasyBCD but that wont work on current windows os like 8 or 10, I dont think its compatible with uefi. All the examples of multiboot stuff on google and youtube are for those trying to install an os.  Nobody is designing a bootable usb for choosing which os u want to boot  into.

[Geek-9pm]

This is from dictation. There may be some errors.

Okay, now I have an idea of what you're trying to do.
There are a number of different free boot loaders available out there. But only a few of these have source code available. And of these, I think there is only one that would be useful to you. I am thinking about a version of GRUB used by the Linux community for booting both Linux and Windows on one computer. It is called GRUB 2 and here is a link on Wikipedia that covers all the major boot loaders in common use.

https://en.wikipedia.org/wiki/Comparison_of_boot_loaders

If you have not already done so, please look over this article very carefully. It has the information you need to help you write your own boot loader, if that is what you want to do.
Also, note that some boot loaders are not scriptable. When they say scriptable, it means the boot loader can be programmed with a script that gives it the behaviors you want to load the operating system you want. That is a much better option than trying to write everything yourself from scratch. The script adds very little overhead to the total size of the boot loader and has little impact on the speed of the book loader. The boot load speed is mostly a function of the size of the system and the speed of the hard drive and not a function of how big the script is.
Another alternative would be to purchase one of the commercial boot loaders that have been designed to handle both Windows, Linux and the new firmware now in use on personal computers.
This is the best I can do for you. I've used boot loaders for many years and have learned how to boot different versions of Windows and Linux. But trying to boot from another drive gets to be an issue. The computer firmware wants to boot from just one device. If that device is not available, it tries the next device in the list.
Microsoft has made some adjustments to Windows so that you can now boot Windows from a USB device. With older versions of Windows that was not possible.
I hope this is of some help to you.
And yes, it is possible to use GRUB to boot to either Linux or Windows or even an operating system on another drive. Somewhere in the documentation it's there, but I was not able to find it myself and I ended up needing to use the firmware to switch to another device.

End of my dictation.

[modobo]

Hi Geek, thanks for the info, I will start investigating GRUB2 right away. I will let u know how its going and how it goes, with xmas approaching, I wonder when I get done learning GRUB2 but the tortoise always reaches its destination.

[Lisa_maree]

Hi

Perhaps check out this boot loader http://www.rodsbooks.com/refind/

There is a lot of information on the site regarding why the program is needed and how to get the best from the program

And there is a ton of info here https://software.intel.com/en-us/articles/beyond-bios

[modobo]

  Wow, good work Lisa, thanks