I am new to this site as a member but have consulted its answers quite a lot of times. Besides my questions regarding OS Development hasn't been answered in any forum.

1. In OS Dev. we make a bootloader. The org point is 7C00H. Why so? Why not 0000h?

2. What are the last two signatures in the bootloader used for? People on every forum have answered that it is important for the system to recognize it as a bootable media. But I want a specific answer. What do each of those signatures do.

3. I have the basic concept of a kernel. Point is.. it relates to different files required in a system. It sort of binds up everything that is individually developed. Now the thing is that that I have floating ideas in my mind regarding different aspects like keyboard, mouse, etc.. how do I put them all together? Which should I start with first?
   If possible please provide a step by step procedure of the startups of the kernel.

4. Suppose I have developed my language entirely in C and Assembly. Now questions is will exe files work on my system.. if it doesn't then I have to create my own files and publish them. Which is a bad idea.. next step would be for me to go for a compiler for a language which I have designed myself. Now the point is.. How do I implement the compiler into my OS?

5. After all this my final question is that.. How do you go about multitasking and multithreading? and I don't want to use int 21h as its dos specific.. how do I go about making files, renaming them, etc. and all assembly books teach 16 but programming.. how do i go about doing 32 bit or 64 bit with the knowledge I have.. if the basics and instructions are the same.. I don't mind.. but how do i go about otherwise?

Don't tell me to give up the idea because I WON'T. And don't tell me it's too complex because I have a sharp knowledge of working of a system, C, Java, Assembly, C++ and python, C#, visual basic.. and not just basics but full fledged api developments.. but I really want to go deep into the systems part.. so I want professional help..

And I have gone through many OS project files but I want help particularly from this site as there are people with knowledge depth who can guide me the right way.

And please don't suggest any books above 20$ and they should be available on flipkart as amazon charges massively for shipping and I prefer free shipping from flipkart.