Whats the relation between a linux OS and a kernel?

Question

Ive been using linux for several years, but never stepped beyond installing from cd/dvd and if the app manager dint have what i was looking for in software then i was a lost case.

but right now im trying to get a grip around whats "linux"?

first word that pops into my head is "kernel". after reading on wiki i understand that kernel is software running to give other software(OS+apps) access to hardware(CPU, RAM+++). it also handles memory... but isnt that what the OS suppose to do(what i remember from OS class @ school).

Is the Linux distro just a packed list of software?

Take my favorite distro: fedora. its now in version 14 and ships with kernel 2.6.35.

My theory is: does the kernel come from somewhere central and is the core of EVERY linux distro? if this is true then the linux distro is just a way of making the computer with the kernel more userfriendly to use? in that way the distro+kernel = OS because the one without the other is not usable (maybe pure kernel, but who sits on that?)

what ya think? am i on to something?

Answer 1

Linux is the kernel (I find myself channelling RMS here). That's what Linus wrote and that's what the kernel developers continue to work on today. It controls the hardware.

An operating system is something that includes a kernel plus quite a few lower-level "applications" to allow you as a user to do useful stuff with your computer (think file manager, control panel and so on).

A distro is an operating system packaged with an absolute bucketload of higher-level applications like DVD authoring tools, web browsers, office suites and so on ad-near-infinitum. Even Windows does this to some extent, with the inclusion of Wordpad, Calculator and Paint, though not to the insanely prolific level that Linux distros extend to - do we really need 472 different file managers? Choice is good, yes, but only up to a point :-)

Now there are grey areas between kernel/OS and even OS/distro but I think that's a fair starting point for understanding how it hangs together.

Answer 2

Pretty much correct. To me, "linux" is just the kernel. But it is pretty common to refer to entire distributions as linux. That is what annoys RMS so much. He maintains it should be called GNU/Linux, as he sees distributions as the linux kernel plus the additional software from the GNU project. This makes sense too but I never use the term GNU/Linux. I am either talking about the kernel linux, or "linux distributions", or a specific distribution.

So yes. A distribution is just the kernel (which may include distribution specific patches) plus all the extra programs that make it usable.

The kernel is a central project, and is nominally the same in each distro, but most distros customize it a bit.

And the extra software doesn't just make the kernel more user friendly, it makes it usable at all. A kernel is just interrupt handlers, device drivers, and system calls. It basically virtualizes the hardware and provides a standard environment for programs to work on.

As far as the phrase "operating system" goes, it can be confusing. Some people may say the kernel IS the operating system, and everything else is either a utility or an application or something else. Other people may say the kernel plus some other packages make up the operating system, but most of the software is not part of the operating system. Others may say all the software in the distro forms part of the operating system.