RWMBX, SYSTEM_MGMT, Identifies which mailbox caused RWMBX Identifies which mailbox is causing an RWMBX process state. A process enters an RWMBX state when it attempts to write a message that is bigger than the remaining space in a mailbox. The writer remains in RWMBX until another process frees up sufficient room in the mailbox by reading messages that are already qued there. RWMBX is typically caused by a reader that has unexpectedly terminated, faulty logic in the reader process or overwhelming mailbox thruput generated by several writers. In the case of multiple writing processes, the writer with the smallest message gets priority. Processes with larger messages may find themselves stuck in RWMBX. Short of learning SDA fairly well, it is difficult to determine which mailbox is causing the problem. RWMBX attempts to identify the offending mailbox by providing information that is currently not visible using VMS utilities. Specifically, the initial mailbox buffer, the remaining buffer and a count of queued messages is displayed for every mailbox. On a well tuned system, initial buffer is equal to remaining buffer and the qued message count is zero. In other words all messages are being instantly read. Conversely, a mailbox causing an RWMBX state will have a nonzero qued message count and a remaining buffer near zero (or at least smaller than the message the writer is attempting to send). RUNNING RWMBX First define RWMBX as a foreign image. $ RWMBX:==$[disk]:[directory]RWMBX.EXE Invoke RWMBX to display information on all mailboxes on the screen: $ RWMBX To direct RWMBX output to a file and not to the screen: $RWMBX >filename To monitor a single mailbox continously: For example to monitor mailbox MBA99 once a second, $RWMBX <99 Please note the EXE provided is Alpha only produced under VMS 6.2. If you need to run RWMBX under VMS 7.1, the object will have to be relinked. See the source file RWMBX.C for compile and link instructions. Have fun, Doug Wyrembek