[linux-audio-dev] about MIDI timing...

Hello list... I am curious to research further about MIDI timing and here is something I want to ask... I wonder, if we missed the (MIDI?) event a bit (perhaps 1 miliseconds?), what would happen? I guess it will be underrun? Or technically, do we determine a playback as "choppy" by calculating the time difference between sending two successive MIDI events? I don't know much about this issue, so I will gladly receive any thoughts. On the other hand, last night I observed how timidity++ works by using strace and I found no *sleep() (nanosleep, msleep and friends). Does it mean, major MIDI software synthesizers use non system sleep mechanism for the timing? I also read that not all Linux kernel sound card driver enable the internal card timer, thus the software must rely on system timer. Is it correct? thanks in advance for your help and attention. regards, Mulyadi