If you use UNIX, you know that it can be a technically challenging environment. And if you're like most users, you have a job to do aside from exploring your operating system -- like analyzing that hot new stock, running another experiment, or typesetting another report. What happens when you have problems? What happens when the system slows to a crawl, when you can't get logged back in after a power failure, or when you've sent a file to the printer...