Not all that is happening is at the kernel level - there is more and more cruft being done at the microcode level (some due to threats of the folks in DC that want to be able to compromise any and all computers (like this will never blow up in their faces (idiots))). This has the effect of making run time of even assembly code non determent.
Most likely powering down a peripheral chip will have a way to be disabled, but it needlessly increases complexity. I suppose in the end the market place will punish those that do stupid things - sadly that does not apply to the wizards in the government. A friend of mine was writing assembly code for an ARM chip where time of each cycle mattered. It turned out that if the code ran from the built in flash memory - sometimes the fetch would take longer than other - only moving the code to RAM solved the problem. What this means is that most modern hardware can not really do what I call 'determinant real time' - There are calls outside of user and system control that steal cycles and no way to predict the worst case. The good news is the hardware is mostly fast enough that we can still respond in micro seconds. I recently 'rooted' a droid device - and found that there was still code running that I did not have access to. I dumped that one and bought a Chinese droid device that lacked this 'feature'. (I assume that all devices are compromised - I don't think it prudent to ever store passwords on a connected device anymore.) -------------------------------------------------------------------------------- Karl Schmidt EMail [email protected] Transtronics, Inc. WEB http://secure.transtronics.com 3209 West 9th Street Ph (785) 841-3089 Lawrence, KS 66049 FAX (785) 841-0434 99% of lawyers give the rest a bad name. -------------------------------------------------------------------------------- ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60134071&iu=/4140/ostg.clktrk _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
