Storing messages in separate user logs

Using user logs, each user has an individual user log data set. The user log data set can be either a sequential data set or a member of a partitioned data set.

To implement user logs, use the LOGNAME operand of the SEND PARMLIB parameter in IKJTSOxx. For LOGNAME, specify the qualifier(s) for the user log data set name. You can also specify a member name in parentheses. The other qualifier of each user log data set is the user's user ID.

Note: User log data set names should not conflict with system data set names.

The naming convention used for the user log data set depends on the MSGPROTECT operand setting:

If the MSGPROTECT operand of the SEND PARMLIB parameter is set to OFF, the first-level qualifier of each user log data set is the user's user ID. Therefore, for each user, the user log has a data set name of userid.LOGNAME, where userid is the user's user ID, and LOGNAME is the qualifier you specify on the LOGNAME operand.
If the MSGPROTECT operand is set to ON, the user's user ID is the last qualifier of each user log data set. Therefore, for each user, the user log has a data set name of LOGNAME.userid.

If you specify user logs as members of a PDS, make sure the logical record length (LRECL) of the PDSis adequate to prevent messages from being truncated. This is particularly important if you use the exits to append information to messages that are stored. However, the LRECL of the PDS must not exceed 150.

A user log requires a minimum of one track for each user. You can save space by defining user logs as members of a partitioned data set. However, TSO/E does not compress a PDS. If SEND needs to store a message, SEND rewrites the member in the PDS. If your users receive a considerable amount of mail, you may eventually run out of allocated space in the PDS. In this case, you may want to use sequential data sets for some of your user's user logs.

LISTBC allocates user logs using the following data set attributes:

RECFM: fixed-blocked
LRECL: 150
BLKSIZE: 1500
Primary tracks: 1
Secondary tracks: 2

Note: The above space attributes can be overridden using the USERLOGSIZE operand under the SEND statement in PARMLIB member IKJTSOxx. For more information, see .

For members of a PDS, LISTBC uses a value of 20 for the number of directory blocks.

You can use the LISTBC pre-allocate exit to allocate your own user logs with attributes that are more suitable for your different users. For more information about the exits, see Writing exits for the SEND, OPERATOR SEND, and LISTBC commands.

For information about implementing user logs, see Converting from using the broadcast data set to user logs.

You can also use individual user logs for some of your users and continue to use the broadcast data set as the message repository for other users. For more information, see Storing messages in user logs and the broadcast data set.