An insightful analysis of the problems that opaque systems can cause for users, customers - and vendors themselves - from the section "The Perils of SHUTDOWN":

An insightful analysis of the problems that opaque systems can cause for users, customers - and vendors themselves - from the section "The Perils of SHUTDOWN": "One of the other perils of SHUTDOWN is simply that it is so buggy. In fact, the whole SHUTDOWN/WARM START/CKPT START subsystem is just full of bugs, especially in I/O error recovery. The VM community is subjected to altogether too many cold starts as a result. The bugs stay there because IBM provides us with no means of diagnosing problems in this subsystem. When there is a failure in shutting down or starting up, CP is too sick to take a dump of itself. IBM doesn’t provide its VM customers with a standalone dump facility, so it gets very few dumps of shutdown and startup failures. If you begin seeing failures of this subsystem, I urge you to get hold of a standalone dump program from one of the other SCPs and take dumps and report the problems to IBM."