After noticing that the time was spuriously racing of into the unknown while calling gethrtime() I searched out the problem. It was a fault in the code dealing with the 8254 counter underflowing. I suppose it doesn't affect pentium mashines. anyway in rtlinux-2.0/rtl/schedulers/i386/rtl_time.c in the function: global_8254_gettime() the offending line: (118) offset_time += ((c2 < last_c2) ? (last_c2 - c2) / 2 : (last_c2 - c2 + LATCH2) / 2); LATCH2 was defined as 0x8000 i cant see how it fixes the rollover. So I replaced it with some masking tape: offset_time += ((c2 < last_c2) ? (last_c2 - c2) / 2 : ((last_c2 - c2)&0x0FFFF) / 2); and that is all. --- [rtl] --- To unsubscribe: echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED] ---- For more information on Real-Time Linux see: http://www.rtlinux.org/~rtlinux/