Linked by Thom Holwerda on Mon 21st Nov 2011 11:25 UTC, submitted by moondevil
OSNews, Generic OSes You all know MINIX - a microkernel operating system project led by Andrew Tanenbaum. The French Linux magazine LinuxFr.org has an interview with Andrew Tanenbaum about MINIX' current state and future. There's some interesting stuff in there.
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RE[2]: MicroKernel's
by smashIt on Mon 21st Nov 2011 14:35 UTC in reply to "RE: MicroKernel's"
smashIt
Member since:
2005-07-06

That's all well until you consider that XNU (Mac OS X) and NTOSKRN (among others Windows 7) are both NOT monolithic kernels.


you have to be more precise with the nt-kernel
in the beginning it was not a real microkernel, but pretty close to one
after nt4 they went more monolithic
and since vista they are moving back to the micro-side

today win 7 even survives a crash of the graphics-driver

Edited 2011-11-21 14:35 UTC

Reply Parent Score: 4

RE[3]: MicroKernel's
by lucas_maximus on Mon 21st Nov 2011 17:39 in reply to "RE[2]: MicroKernel's"
lucas_maximus Member since:
2009-08-18

Tbh, it survives it most of the time. I had google maps crash a intel display driver yesterday ... first time I have seen a graphics driver crash take down Win 7.

For somereason the laptop had a Windows Vista Driver on a Win 7 machine ... updating seemed to fix it.

Edited 2011-11-21 17:50 UTC

Reply Parent Score: 2

RE[4]: MicroKernel's
by JAlexoid on Mon 21st Nov 2011 23:56 in reply to "RE[3]: MicroKernel's"
JAlexoid Member since:
2009-05-19

Tbh, it survives it most of the time. I had google maps crash a intel display driver yesterday ... first time I have seen a graphics driver crash take down Win 7.

For somereason the laptop had a Windows Vista Driver on a Win 7 machine ... updating seemed to fix it.

Lucky you, I get those crashes twice per day.

Reply Parent Score: 3

RE[3]: MicroKernel's
by galvanash on Mon 21st Nov 2011 19:11 in reply to "RE[2]: MicroKernel's"
galvanash Member since:
2006-01-25

I've posted this numerous times before on this board, but here it goes again...

1. According to Dave Cutler (NT Chief Architect), quoted in numerous interviews, NT is not, was not, and was never intended to be a microkernel. If anything it was based loosely on VMS, which was certianly not a microkernel. That label got thrown about by marketing people for totally invalid reasons (the quotes are hard to find because they were in print journals, but I have seen at least 2 myself).

2. Tanenbaum himself has stated unequivocally that NT was never a microkernel: http://www.cs.vu.nl/~ast/brown/followup/

"Microsoft claimed that Windows NT 3.51 was a microkernel. It wasn't. It wasn't even close. Even they dropped the claim with NT 4.0."

3. By the commonly accepted definition of a microkernel, it simply doesn't come close and never did. The VM subsystem, the file systems, and numerous other subsystems are kernel mode, and always were kernel mode. The do not run in userland, never did run in userland, and were never intended to run in userland. It was in no significant way different from linux or any other monolithic kernel from the point of view of memory seperation.

4. In 3.51, the VDM (video display manager) DID run in userland, along with its drivers. This was done to protect the kernel from driver faults. In practice this had 2 problems. First it was slow. Second it more often than not didn't work - if a fault put the VDM in a state where it could not be restarted the whole system had to be rebooted. They reversed this in 4.0 and moved the VDM back to the kernel. Regardless, this does not make it a microkernel - they simply chose to run this one subsystem this way. Moving it back to kernel mode required pretty massive changes - if it were designed as a microkernel it would have been simple...

I post this because Microsoft marketing was so successful at calling NT something it was not that even 16 years later this misinformation still manages to propogate around. There is nothing wrong with NT - it is a well designed monolithic kernel. But it is not a microkernel and never was.

Edited 2011-11-21 19:14 UTC

Reply Parent Score: 9

RE[4]: MicroKernel's
by DeepThought on Mon 21st Nov 2011 21:06 in reply to "RE[3]: MicroKernel's"
DeepThought Member since:
2010-07-17

To your 3rd point: I never saw a definition that says, all "modules" attached to a micro-kernel have to run in user mode.

Reply Parent Score: 1