Jeremy, Further to your: > How will you prove that your channel implementation, using locks, > will behave exactly like a CSP channel when embedded in some arbitrarily > complex network? Did INMOS ever do this for the transputer implementation of a CSP channel? This seems to be exactly the same problem. In fact, the `monitor' implementation in JCSP (now with a correct ALT ;-) is *very* close to the transputer implementation ... the monitor locks appear in the transputer as uninterruptable micro-code. [This throws another angle on the `low' versus `high' level argument! Those monitor primitives, including "wait" and sort of including a "notify" map to micro-code elements that were used to implement channels etc. in the transputer. So, those monitor thingees seem pretty `low-level' in that context :-)]. But, seriously, does anyone know if INMOS ever proved their channels were CSP ones? I don't remember anyone ever asking ... Peter.