You can store all SEND messages in the broadcast data set, or you can use individual user logs to store the messages. IBM® suggests implementing user logs to avoid the single point of failure that exists if all users rely on the broadcast data set for their individual mail. If you use individual user logs, you can use them for some of your users and use the broadcast data set for other users by writing exits for the SEND, OPERATOR SEND, and LISTBC commands.

User logs provide large processor constraint relief by eliminating possible contention for the broadcast data set. If your installation has large processors, such as the IBM 3090, the system could experience contention when users store or retrieve large numbers of messages at one time from the broadcast data set. By using user logs, you might decrease possible contention for the broadcast data set.

With RACF® installed, your installation may be using security labels (SECLABELs). User logs can be set up to protect messages from being viewed by a user who is not logged on at the proper security label. The MSGPROTECT operand of the SEND PARMLIB parameter is used to indicate whether the individual user log data set is security protected from the user. For more information about the MSGPROTECT operand see . For information about setting up security labels, see .

If you use user logs, each user has an individual user log data set. The data set can be either a sequential data set or a member of a partitioned data set (PDS). SEND stores messages in the user log data set and LISTBC retrieves messages from the user log. When SEND stores the messages in the user logs, SEND truncates the trailing blanks. The command syntax for the SEND and LISTBC commands and the OPERATOR SEND subcommand is unaffected by user logs.

If you use user logs, OPERATOR SEND stores notices in the broadcast data set and LISTBC retrieves the notices from the broadcast data set. Notices are messages that the SEND subcommand of OPERATOR stores for all users on the system. The use of user logs does not affect the storing and retrieving of notices.

The following topics describe how to store messages in the broadcast data set or in user logs.