Christian Klippel wrote:
hello iohannes and all,
Am Samstag 19 November 2005 00:13 schrieb IOhannes m zmoelnig: [...snip...]
please note, that the word "latency" is nowhere mentioned. it has nothing to do with "realtime". (you can have a hard realtime system that has a delay of 1 week). so pd is by design a realtime system.
ouch! that comment about hard realtime is plain wrong. hard realtime is used in systems where you need minimal delay, like engine controls, medical systems, etc.
i guess i was unclear (at least i was cryptic) "real-time" does say _nothing_ about the "amount of latency". however, the important thing is, that "realtime" guarantees processing within a "given latency" (however large that may be).
imagine your life support systems would use hard realtime that can delay up to a week .....
the most important aspect of hard realtime systems (like rtlinux) is that they have the lowest latency possible!
no, the most important thing is, that they have a maximum latency aka "deadline" that must not be exceeded.
also, see here: http://en.wikipedia.org/wiki/Real-time_computing
quoting this artile:
"It is important to note that hard versus soft real-time does not necessarily relate to the length of time available. A machine may overheat if a processor does not turn on cooling within 15 minutes (hard real-time). On the other hand, a network interface card may lose buffered data if it is not read within a fraction of a second, but the data can be resent over the network if needed, without affecting a critical operation, perhaps without a delay noticeable to the user."
but then i am no real time specialist.
mfg.adr IOhannes