Andy Tanenbaum Releases Minix 3

Guillaume Pierre writes "Andy Tanenbaum announced the availability of the next version of the Minix operating system. "MINIX 3 is a new open-source operating system designed to be highly reliable and secure. This new OS is extremely small, with the part that runs in kernel mode under 4000 lines of executable code. The parts that run in user mode are divided into small modules, well insulated from one another. For example, each device driver runs as a separate user-mode process so a bug in a driver (by far the biggest source of bugs in any operating system), cannot bring down the entire OS. In fact, most of the time when a driver crashes it is automatically replaced without requiring any user intervention, without requiring rebooting, and without affecting running programs. These features, the tiny amount of kernel code, and other aspects greatly enhance system reliability."In case anyone wonders: yes, he still thinks that micro-kernels are more reliable than monolithic kernels ;-) Disclaimer: I am the chief architect of Globule, the experimental content-distribution network used to host www.minix3.org."

Comments

Re:This guy told linus

[LizardKing]

Linus would have deserved that "F" in operating system design, but he wasn't writing his kernel to get grades on a computer course. If he had been then he probably wouldn't have written a crude, monolithic kernel that was totally unportable. Apart from the crudity of it, those were his explicit goals - to write a monolithic kernel that would run optimally on his 80386. (Bear in mind that the Linux kernel we know today is pretty far removed from that early version in design and implementation).

As for AT, he's a very smart guy. He writes books on operating system deign and networking that clearly describe quite complex topics. Even if you don't like the idea of microkernels, the "Operating Systems ..." book that describes the Minix kernel is an excellent read.

Tanenbaum gets a failing grade

[idlake]

Tanenbaum rightly criticized Linus for creating a big monolithic operating system kernel, but at least Linus was copying something that was successful and he made it a success himself.

But, geez, how often do microkernels have to fail before Tanenbaum will admit that there must be something fundamentally wrong with his approach, too? Microkernels attempt to address the right problem (kernel fault isolation), just in such an idiotic way that they keep failing in the real world. But instead of a detailed criticial analysis of previous failures, Tanenbaum and Herder just go on merrily implementing Minix3, apparently on the assumption that all previous failures of microkernels were just due to programmer incompetence, an incompetence that they themselves naturally don't suffer from.

Both Linux-style monolithic kernels and Tanenbaum-style microkernels are dead ends. But at least Linux gets the job done more or less in the short term. In the long term, we'll probably have to wait for dinosaurs like Tanenbaum to die out before a new generation of computer science students can approach the problem of operating system design with a fresh perspective.

Re:Love this quote

[MikeFM]

That'd be more convincing if I could see a microkernel OS that didn't suck. The theory is great.. sort of like object oriented programming.. but doesn't always work out. The biggest problem seems to be that that extra layer of abstraction slows things down (which makes sense really). Then you have to weigh the benefits of running faster and leaner or easier programming. From a programmers point of view most will like the abstracted and easier option because you can spend more time writing code and less time debugging and fixing but real world usgae doesn't always work well with that.

Still.. as fast as modern computers are I think we may be reaching a point where raw speed is less important and well designed microkernels can probably run almost as fast as monolithic kernels. If heavy usage servers can be run as virtual machines in Xen then why not use a microkernel too?

So. Any examples of microkernel OS's that handle heavy server load, function well as a desktop, and can handle multimedia tasks like gaming? OS X uses BSD under a microkernel I think but my experience is that it is slow and the tests I've seen have shown that Linux performs a lot better on it than OS X (no idea if that was due to microkernel use). I'd find it hard to believe that with solid numbers showing that microkernel is just as fast and without additional overhead that someone like Linus wouldn't use it since it's an easier programming model (better for security, stability, etc).