The operating system doesn't actually receive signals, it receives system calls.
As for who makes the system calls: Everything in userspace, usually through the use of the Standard C Library.
Yes, Linux is like an operating system much like Windows OS or Mac OS. Linux is kind of like a community of Operating Systems. A popular OS from Linux is Ubuntu.
Android is a Linux OS
Apple is more popular Linux is ok OS is Crap. There you go! You got an answer!
Ubuntu is a Linux distribution (as in a specific OS setup with the Linux kernel.)
Linux.
Most Linux OS's walk you through dual booting. Choose your prefered Linux OS and burn it to a disc and run it. You could also partition your hard drive from the XP side and create a space for your Linux OS to run in. If you are new to Linux, it is recomended to run the OS without actually installing it, that way you can get the feel of Linux without completely installing it.
LINUX and UNIX are vendor independent OS
nokia mobile supports windows OS and the sony erricission ,Motorola supports Linux OS.
Yes. I will send you the syllabus of Linux and CCNA.
Mac-OS=Disk operating system==Linux OS==Windows OS==Unix OS=
If you are starting and new to Linux try Zorin OS. If you are experienced and know more about and how to use Linux the get Ubuntu.
The most popular one is the Android OS.