i remember a fellow student debugging an lsi11 kernel using a form of analogue vectorscope. i think it had a pair of DACs attached to the upper bits of the address bus. it generated a 2d pattern which you could recognise as particular code - interrupts are here, userspace is there, etc. the brightness of the spot indicated the time spent, so you got a bit of profiling too - and deadlocks became obvious. anyone remember these, what where they called? i think it was an HP or Tek product. -Steve