Well, I have never used Tru64, so I'm not sure how hard that will be. But at some level the answer is yes, it is possible. A sleeping process will have a value usually called a "wait channel" that relates to what it is waiting for. ps often can display this field labelled "WCHAN" or something like that. It is a address in the kernel's memory space. Sometimes you can figure it out with adb. Some recent BSD versions actually decode this field. HP has a product called Glance that can decode it for HP-UX. I know that HP has a version of Glance for Solaris. I don't know if they have one for Tru64 or not. If they do, it is worth getting. It is the best performance tool I have seen.