what are prerequisites for OS dev? I mean for kernel development? Do we require to do assembly in some parts or we can use C for each and everything

Kernel development can't all be in C. There has to be at least some assembly. But most of it can be in C.

prerequisites?

cant be C code converted to assembly? bdw which assembler do you use?

What do you mean by prerequisites? If you want to do kernel dev you just read a book about it. I don't think there are prerequisites. Of course it is a large topic and it would help to learn how cpus work.

There are things that aren't expressible in C such as how to change from 32 bit to 64 bit mode on an x86 processor. That kind of thing is best done in x86 assembly. Most of a kernel can be written in C though.

Also, C depends on having an environment in place (such as having a stack for local variables and a data section for global variables). An OS needs to be able to run from before those things exist.

read some articles and blogs , looks like assembly is not as tough as you see it, obviously you need to write more code but if you understand pointers , its easy , isnt it? Or Am I missing some nasty part of it?

Have you ever written in assembly? It's similar to C, in my opinion.

just started , :P