I have heard that it does not work in 64bit mode. For more information on how to get SUNWski look at this EMail . A better source would be the timestamp of a keyboard interrupt, a disk interrupt or a network card interrupt. Unfortunately I do not know enough of the Solaris kernel internals to find the right entry points. Maybe it is possible to use the 'kstat' sturct to mix the data pool.
Help is quite welcome.
An other point is that the high resolution timer on old hardware may not have a very high resolution.