Swapping the current log frees the log for immediate printing. To swap the log, use the LOGSWAP command. Swapping the log is possible only when another unused log remains to which logging can continue. You can specify up to nine logs. Logs do not need to be consecutive.
When a log is swapped, the log status, the requesting user ID, and the reason for the swap are recorded. You can display these details with the SHOW LOGS command.
Each of the logs is identified in the JCL by the LOG DD name followed by a single digit in the range one to nine.
Example: Log Name
//LOG4 DD SYSOUT=A,FREE=CLOSE
Mixing of device types is also valid. Inclusion of FREE=CLOSE prints the log when it is released by the LOGSWAP command.