Xen is quite useful in providing
ways to dice and slice a server (farm) at different granularity from
processor, core, or thread, and for its isolation, migration, and
multi-OS support. To date, its targetted at Intel and the desk/server side.
What we desperately need is to virtualise handsets and also processors in cars.
Right now, the tussle between the various service providers to create walled gardens has led to a disaster which is that there are now far more OSs (and even just incompatible variants of OSs) in the handset/pda world than any other computign world - linux, symbianos, windows mobile smart phones, nokia, ericsoon and samsung ownbrand OS and re-badged symbian and java and other OS - despite ample resources (CPU and memory in a typical 2006 phone is more than an internet host or router of 1990), these folks produce bluetooth and wifi and camera APis that are stunted, they don't ship location services, or p2p/manet tools, and basically have NO clue- in the interest of short term profit, they misunderstand that the LONG term profit will be bigger if the service*network is bigger (see Metcalf's law, or dave reeds version of it) - killer apps wont "appear" for 3G or wifi enabled phones unless the community can program them. Frankly, its an embarassement.
Don' even get me started on in-car devices... ... ...
So if we para-virtualized them, we'd take these problems away -= application writers could write to a single platform, instead of 11, and know that that platform would work on the VM on any phone - since many phones use either ARM or (a few) xscale, the processor is pretty friendly, so the lower level of a "xen-like" system, would be not too bad - the page sharing stuff in Xen 3.0 would allow a lot of efficiecies too so the memory footprint of running n variants of Symbian OS and Linux and windows smart phone OSs, would not be n-times - it would be a fraction more...
show me the money:)