The PDP has been part of VisualWorks since the 7.0 release, but there are still things about it that not everyone understands. In VW, prior to the PDP, it took a halt in code to jump into the debugger - now, of course, you use breakpoints or watchpoints. That's pretty well known now - but being able to debug any arbitrary process in the system isn't so well known. Here's what you do:
- From the launcher, pull down the Debug menu (or hit ctrl-y)
- Select Process Monitor
- Select a process
- Pull the Process menu, and you can debug (or inspect, or terminate, etc) the process.
It's a simple thing - but very helpful in an application that's running multiple processes (like, say, a server). I've made use of this facility in the development of BottomFeeder and the blog server.