Hello everyone! I will be thankful if anyone read this mail. I was reading one of "HOWTO" article "*Implementing a System Call on Linux 2.6 for i386*" http://www.tldp.org/HOWTO/html_single/Implement-Sys-Call-Linux-2.6-i386/ I am a B.Tech computer science student and new to Linux kernel. I am following a book *"Understanding Linux kernel 3rd edition " by Bovet and Cesati*. As your time is much much important so i am writing the purpose of this mail in points : 1. I want to understand and implement process basics , how system calls works , inter process communication , *adding new system calls and interfaces in API , adding new functions to "libc and call these interfaces and system calls from user program" * etc. 2. The method you told does not add anything to API or libc , i want to implement system call through API or glibc , so that there will be no need of creating "testmycall.h" (header file ) while writing a test file to test newly created system call. 3. How the Linux kernel interact with the hardware (i want to go in such a detail so that i can make such a customizable Linux kernel so that i can use that kernel to open my home door , its a example only , i want to understand and use it to perform my experiments) I think you have got the purpose of this mail , so ITS HUMBLE REQUEST CAN YOU TELL ME THE DIRECTION WHERE I SHOULD MOVE , ANY BOOK TO UNDERSTAND THESE BASICS SPECIALLY *ADDING SYSTEM CALL USING API / LIBC *, ANY LINK YOU HAVE AND ANY FORUM WHERE I CAN POST QUESTIONS . Thank you so much for your kind help. SAURABH JAIN