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World's First Formally-Proven OS Kernel
An anonymous reader writes "Operating systems usually have bugs — the 'blue screen of death,' the Amiga Hand, and so forth are known by almost everyone. NICTA's team of researchers has managed to prove that a particular OS kernel is guaranteed to meet its specification. It is fully, formally verified, and as such it exceeds the Common Criteria's highest level of assurance. The researchers used an executable specification written in Haskell, C code that mapped to Haskell, and the Isabelle theorem prover to generate a machine-checked proof that the C code in the kernel matches the executable and the formal specification of the system."
Does it run Linux? "We're pleased to say that it does. Presently, we have a para-virtualized version of Linux running on top of the (unverified) x86 port of seL4. There are plans to port Linux to the verified ARM version of seL4 as well." Further technical details are available from NICTA's website.
but is the spec useable ? bugfree ?
Yes, I'm left. You have a problem with that?
"Beware of bugs in the above code. I have only proven it correct, not tested it."
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
There is an old corollary that says, you cannot get from the informal to the formal by formal means. All they have proven is, that two specifications contain the same bugs. Both specification were formal (Haskell, C). This is the same as having Perl and Python code and you to prove they implement the same functionality. Neither is a proof, it is bug free (informal definition of bug, not if a bug is specified it isn't a bug).
I thought any sufficiently complex system was impossible to prove correct.
Then obviously this OS is not sufficiently complex.
Most faults on most platforms are caused by hardware faults
bullshit.