First Post-Need some information about starting hardware programming and other stuffs

Hi,

recently I find my interests in hardware programming and mobile device low level programming. there are some questions in my mind which i could not find the proper answers for them. before expressing my questions i think it would be necessary for you to have a background of my knowledge. as i think i am an average programmer. not a low level programmer. i can learn everything if i find it's start. by the way, i have some knowledge in c/c++ java programming. and a little in assembly. just a small guide (even a name) can lead me to the very end of the subject.

questions:

how a mobile device operate in it's low level(for example a nokia s40 device)
what a mobile hardware consist of?
how can i communicate with a hardware?
how can i create my own operating system for a mobile device?
how can i read the ROM of a device without using any third party applications?
where should i start to find the answers of all this questions?

Thanx in advance.

From the sounds of it, I suspect the answers that you need will be quite long. As a suggestion, you may need to read up
on the following topics (and I've given some example books and links).
Microcomputer and Microcontroller chapters in 'The art of electronics', or this book (which will help but is not as good).
Study a book on OSs, such as this one (downloadable).
For low level work (kernel level): far more intensive C knowledge. Start with 'The C Programming Language'.
For non-kernel work: far more intensive C++ knowledge. Start with the book by Stroustrup.
For applications: Learn the API and entire ecosystem of the smartphone system you're using!

thnx sky. i owe you one

Another question comes to my mind. should i begin with the Art of electronics? should i start from electronics to software or from software to electronics. or proceed both of them at the same time?

AoE has chapters describing microprocessor operation, so those are the sections that will be of interest to you.
They directly explain how devices operate at their lowest level (machine instruction set).
Learning this, and learning what assemblers and compilers do, are the first step towards OS (well, kernel)
implementation. You'd also need to study OS theory. That covers the "how can i create my own operating system for a mobile device?"
question that you had.
For the "how can i communicate with a hardware?" question, you'd need to understand a variety of protocols. It should
probably come later, after you've got good microcontroller knowledge, and good C knowledge.
If you want to just do application programming, none of the above is essential.