[ale] How do people deal with RHEL?

[Michael Trausch]

On 03/24/2011 04:36 PM, Chris Fowler wrote:
> I think it is still considered monolithic even if they are modules and
> linked into the kernel at run time.

Linux has historically been a monolithic kernel, but functionality has 
been added to it that is distinctly microkernel functionality; today it 
could be considered to be a hybrid of sorts; the style used to implement 
kernel module loading and unloading, the FUSE and CUSE drivers, and 
other things that pass messages back and forth between userspace and 
kernel space can all be argued to be microkernel style functionality.

There have also been discussions in the past about modifying the 
kernel's structure, migrating from a predominately monolithic style to a 
predominately microkernel style.  Given that since those discussions the 
kernel has gained quite a bit of functionality styled that way, I'd 
wager that we'll see it gradually become more and more like a microkernel.

> A microkernel has drivers that communicate with the kernel as a form of
> IPC.  The benefit is that failure of a driver in most cases will not
> take down a system.  The con is that a micro with this mess of
> communication is much harder to implement than a mono.

Depends on how you implement it.  Sometimes, as with the Hurd, the 
hardest part is getting people to write drivers for the thing.  The 
kernel itself is largely complete, but lacking in hardware support (and 
thus lacking in the ability to be used on bare hardware).  However, the 
Hurd supposedly works really well in virtual machine environments.  I 
haven't attempted to use it in several years, however.

	--- Mike