Re: [LIH] MINIX

[Nick Hill <nikhilwiz@xxxxxxxxx>]

--- Kedar Patankar <kedar@xxxxxxxxxx> wrote:
> 	Well, if you say that just having LKM makes a
> kernel architecture
> somewhat of a microkernel arch then why not count
> plain old dos and win3.1
> also as microkernels? They also had LKM. And I know
> of several boxes,
> embedded devices that use the plain old M$ dog as
> base system, w/o a
> display interface or keyboard interface, but with a
> dos extender (like
> phar-lap) to let them access more ram.
> 

Please let me remind u that LKM was not the ONLY
reason i gave for Linux having a few of micro-kernel
features. 

> 	Suitability to embedded systems doesn't qualify a
> kernel to be a
> microkernel. That way one can claim that VxWorks and
> pSOS and uCOS and
> eCOS and all those nifty embedded OSes are
> microkernel arch. They are not.
> They are all classical monolithic kernels.
> 

But it sure facilititates an O/S to get into embedded
devices...

> 	IMHO what distinguishes a microkernel architecture
> is when you
> have the ability to have *whole* filesystems,
> page-fault (or any other
> fault) handlers, and stuff like that to be runnable
> as a user space
> daemon, no more different than any other application
> prog, except for
> privileges/access permissions.
> 
> 	I say again, please don't confuse ability to have
> LKMs with a
> microkernel arch.
> 

point taken.

i still think there is a small effort to adopt some
micro-kernel features into the kernel. i think ioctls
are a lil' bit like message passing in
micro-kernels...
i dont think u've observed but there're a few "user
space" drivers in linux too. to name a few... GLIDE
drivers for a 3dfx card, v4l drivers for a pixelview
card, pcmcia drivers, etc... so u see, there is a
small bit of a micro-kernel like approach in linux,
altho most of the linux kernel is shaped in a
monolithic fashion, as it was meant to be that way,
atleast, when Linus started out...


Nikhil.

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