The PARKBENCH suite of benchmark programs provide low-level benchmarks to characterise the basic communication properties of a parallel computer by measuring the parameters (\rnhalf) for communication (COMMS1, COMMS2, COMMS3). The ratio of arithmetic speed to communication speed (the hardware+compiler parameter \fhalf for communication) is measured by the POLY3 benchmark. The ability to synchronise all the processors in a parallel computer in an acceptable time, is a key requirement of such computers. The SYNCH1 benchmark assesses this by measuring the number of barrier synchronisation statements that can be executed per second as a function of the number of processors taking part in the barrier.