On Saturday 13 January 2007 08:10, wireless wrote: > Bob Paddock wrote: > > Does anyone know of any Hard Real Time Systems, > > where deterministic response is required, that work > > with Gentoo-Embedded?
> Um, the way you posed your question, is sure to solicit > 'religious wars' on a few issues. The way I posed the question was meant to result in: "Yes, there is a RTOS that works well with Gentoo-Embedded, and it is XYZ at http...." How would you have asked the question? https://www.rtai.org/ is one of the many Linux RTOS extensions out there. Any of them work with Gentoo? I like Gentoo, and simply wanted to use it in a project I have coming up, but it has 'hard' time requirements. http://www.rtnet.org/ comes to mind, as well for the networking aspect of things. A Time Triggered Protocol. > Soft real time, means that timing constraints are soft > or guildlines for process performance metrics. Erlang is a 'Soft' Real Time System, not what I need at the moment. > Hard real time, means the timing constraints are hard > or an absolute requirement. I am aware of the issues, that is why I made the distinction, in what I was after. > to not be 'real time'. But think about if a missile, > is suppose to change it's rudder in response to an > AD input, in 150ns, does it mean that the missile as > as system is a failure if the rudder response is > 151 ns or 150.002 ns? If it is in the targeting system, it makes the difference between hitting the target or not. A 1 ns difference, is a large area to transverse when your missile is traveling at Mach-6. A missed target is a failed Missile System. TechUpdate from the Missile Defense Agency comes out quarterly. MDA funds a lot of research in other areas. The Summer 2006 laying here beside me is about "Phasing out Brest Cancer" using Microwaves. "Fuzzy-logic software" on page ten might be more relevant to this list. Check it out at: http://www.mdatechnology.net/ Maybe someone can make a ebuild for their screen saver? > Determinism is another funny character. Real embedded > systems use a 'state machine' design where every > state or transition is fully characterized and defined. > > ON a large complex system, it is virtually impossible to > discover, characterize, define and test all possible states > of a complex system. Use the appropriate tools and languages such as Esterel. http://www.esterel-technologies.com/ or http://www.tttech.com/ . > (just look at the behavior of a single > female of any given species). Does that fit my requirement of being Deterministic? :-) > Biological systems are but > one example of a system that cannot be fully characterized > due to many factors but genetic modification being one > example. Nor am I building a Biological Entity, at the moment at least. If you want to give that a shot take a look here: http://www.rexresearch.com/crosse/crosse.htm > Embedded linux anything, currently, can never be fully deterministic. Embedded Linux can be run as a task of a fully deterministic RTOS, built with a Finite State Machine if you like. Any done with Gentoo-Embedded? > Using languages such as C++ or more reaching OO languages, only > exasperates the goal of being fully deterministic. In stead of > the educators realizing and admitting that very few things > actually need HRT and virtually nothing complex that we build, I know what I'm building, as well as being well aware of the high importance of System Design Requirements. > <flames on> Obviously, you'll find lots of vendors and educated > folks ... But will I find one that actually answered my question? :-) -- http://www.softwaresafety.net/ http://www.designer-iii.com/ http://www.unusualresearch.com/ -- [email protected] mailing list
