>is the windows xp , for instance, considered as the kernel
"Windows XP" refers to the entire operating system. Since everything is closed-source and developed my Microsoft, there's really no reason to have a name for it, although I guess you would refer to it as the Windows NT kernel (as the XP kernel came from the NT series).

>i read this and i didnt really understand what it means , i hope you could help
>in explaining it to me

Embedded systems have a very simple environment for running programs (and in many cases there is no kernel or operating system). Because of this simple environment, it's difficult to separate purely user-based software from kernel-based software as the hardware is usually meant for a single type of software.

Interpreted systems are special because the programs running in them aren't processed by the kernel of the base operating system. For example, Java programs have to run inside a runtime environment, which is like a kernel running inside another kernel, and as such they communicate with the virtual kernel. This makes it harder to distinguish between kernel and user mode.

oh alright, i see what you mean.

well,let's say i bought this new printer, and i plugged it in my laptop, of course it wont work cz the operating system doesnt know how to communicate with this new hardware,

so i install the cd.
well, as i understood from what you told me, the software will be loaded in the kernel to protect it from the user.

my first question: let's assume the cd is loaded in the user mode, how can a user access it , and how can it modify it and mess with it ?

second, let's say i want to print something.
can you tell me how things happen in details in the low level.

i mean, once i click print on the software that i downloaded, how will the os know that i want to print ? and how will the os get the printing job done?

again, thank you so much for replying fast, you are really helping me a lot !

>the software will be loaded in the kernel to protect it from the user.

No, the reason it's loaded into the kernel is because the driver needs direct communication with the kernel and vice versa. It has nothing to do with 'protection' from the user, although it's true that there generally isn't too much communication between a kernel-based program and the user.

>let's assume the cd is loaded in the user mode, how can a user access it , and how can it
>modify it and mess with it ?

In this case, installing the program doesn't actually require running it. An installer program running in user mode, naturally, installs it onto the system. It is then run from your hard drive.

>i mean, once i click print on the software that i downloaded, how will the os know that i
>want to print ? and how will the os get the printing job done?

It's somewhat OS-dependent, but generally what happens is that software sends the printer spooler a document. The printer spooler then decides if the printer specified is local or network-based, and will then send it to the appropriate device. The kernel handles the send requests to a device, and it in turn communicates with the driver, which finally communicates with the printer hardware. That's the basic idea.