On Fri, 04 Aug 2006 15:11:49 GMT John Navas <spamfilter0@navasgroup.com> wrote:

| Not if you look beyond the popular operating systems. True microkernels
| can isolate even device drivers in their own processes (contexts) to
| prevent this kind of compromising (with other benefits as well,
| including robustness and stability). The real problem is Intel
| processor architecture, which has so much process (context) switching
| and inter-process communication overhead that popular operating systems
| resorted to running these functions in the kernel, thus foregoing this
| kind of protection (and robustness and stability). A related problem is
| weak memory management, including lack of Data Execution Prevention
| until recently. For more information on microkernels, see
| <http://en.wikipedia.org/wiki/Microkernel>.

Saying "The real problem" is misleading. While it is certainly real, the
more correct statement is "A real problem". There are others, too, and
just as real. The biggest one I'm aware of is management trying to make
technical decisions beyond that scope of capability, then trying to assert
the authority to do so, anyway, by claiming it to be a "business decision".
Completely inappropriate time schedules are often to blame. But what often
happens is scheduling the elements of the project under false ideas of how
long some aspect (like writing the driver) will take. Because a lot of
driver developers _can_ deliver functional code fast, managers tend to have
the idea that such delivery times represent a _correct_ driver. Performance
and functionality are easy to test, reliability and security under conditions
not anticipated are much harder.

You can have it delivered sooner, run faster, or work correct. Pick two.
Guess which two that most managers usually end up picking.

Don't misinterpret this post as saying the problems with the Intel x86 class
CPUs are not relevant. But ways to work around these problems are known.
They usually do take extra time, which managers don't like.

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| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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