On Wed, 2008-08-27 at 16:48 +0100, Jamie Lokier wrote: > Bernd Petrovitsch wrote: > > If you "develop" an embedded system (which is partly system integration > > of existing apps) to be installed in the field, you don't have that many > > conceivable work loads compared to a desktop/server system. And you have > > a fixed list of drivers and applications. > > Hah! Not in my line of embedded device. > > 32MB no-MMU ARM boards which people run new things and attach new > devices to rather often - without making new hardware. Volume's too > low per individual application to get new hardware designed and made.
Yes, you may have several products on the same hardware with somewhat differing requirements (or not). But that is much less than a general purpose system IMHO. > I'm seriously thinking of forwarding porting the 4 year old firmware > from 2.4.26 to 2.6.current, just to get new drivers and capabilities. That sounds reasonable (and I never meant maintaining the old system infinitely. Actually once the thing is shipped it usually enters deep maintenance mode and the next is more a fork from the old). > Backporting is tedious, so's feeling wretchedly far from the mainline > world. ACK. But that also depends on amount local changes (and sorry, but not all locally necessary patches would be accepted in mainline in any way). > > A usual approach is to run stress tests on several (or all) > > subsystems/services/... in parallel and if the device survives it > > functioning correctly, it is at least good enough. > > Per application. > > Some little devices run hundreds of different applications and > customers expect to customise, script themselves, and attach different > devices (over USB). The next customer in the chain expects the bits > you supplied to work in a variety of unexpected situations, even when > you advise that it probably won't do that. Basically their problem. Yes, "they" actually think they get a Linux system where they can do everything and it simply works. Oh, that's obviously not a usual "WLAN-router style" of product (where you are not expected to actually login on a console or per ssh). > Much like desktop/server Linux, but on a small device where silly > little things like 'create a process' are a stress for the dear little > thing. > > (My biggest lesson: insist on an MMU next time!) ACK. We avoid MMU-less hardware too - especially since there is enough hardware with a MMU around. Bernd -- Firmix Software GmbH http://www.firmix.at/ mobil: +43 664 4416156 fax: +43 1 7890849-55 Embedded Linux Development and Services -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html