Monolothic kernels....
Pros...
1) Easy to write drivers.
2) Fast
3) Simple Design.

cons...
1) 1 faulty driver can crash the whole system.


Microkernels...
Pros...
1) Very Stable, drivers dont run in kernel space, so faulty crashing driver can just be re-started without affecting the rest of the system.

cons
1) A little hader to program.
2) Device Drivers must use message passing instead of driect calling to get anything done... you lose a little performance.



The MacOSX kernel is what they are calling a "Hybrid kernel"
its half monolithic, and half micro.

But this doesnt make much sence to me...

The reason for a monolithic kernel is performance...
so MacOSX uses the FreeBSD kernel to run drivers that need high performance..

for example the 3d graphics cards, networking, disk controlers..

but these things are all the parts of the kernel which are generally less stable, and more likely to crash the system.

Whats the point in having a half microkernel / half monolithic kernel, if every part of the system which would benefit the micro kernel design, is placed into the freeBSD monolithic kernel in the name of performance..

doesnt this sound strange to you ?

 

 

 

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no, it doesn't sound strange to me. Linux is also like a hybrid kernel. You can load and unload drivers especially if one becomes faulty.

xboxrulz

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Linux obviously purely Monolothic, Maybe must be confusing Minix with Linux... ( Minix is a completely differant OS... see http://www.minix3.org/ )

Please try to keep these forums helpfull, do not post flase information.

In Linux, the whole kernel runs with the proccessor in kernel mode.
no part of the linux kernel runs in user land.

Linux = Monolithic,
UNIX = Monolithicm
FreeBDS = Monolithic
XNU = Micro
Minix = Micro.
MacOSX is a microkernel, with the whole FreeBSD system running in kernel mode.

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I look more at Praxis rather than underlying technology theory, because the two often differ.

I've been using Mac now for about 4 years and OSX has been increadibly stable during that time compared to when I used Windows projects for similar tasks. (Windows 2000 Pro was the last version I used and it wasn't too bad)

The only time I had issues were in the early days of OSX when some of our apps had to be run in OS9 emulation (actuall those machines were dual boot so if we really needed to use Quark, we'd reboot).

Sometime I can lock up and crash my Mac, but it's because I'm not paying attention to what all I have open, and when your trying to run Final Cut, Shake, PS, Lightwave, and then go to Open iTunes...yeah I deserve to have it become a paper weight...

Overall I've been extremely impressed with my Mac not only for it's stablity, but for the software as well (I work in video production).

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