Just to clarify, this journal and receiver are in library QUSRDIRDB
<i>…tell me the purpose of the journal QSQJRN…</i>
Journal QSQJRN in library QUSRDIRDB is the journal used by LDAP.
<i>I don’t journal any files on my system, so I don’t know why this journal is active.</i>
System developers are much more careful with their data objects than you are. They know the value of protection. If you list all of the journals on your system, you should find a couple dozen of them or so. All are active, though many might never see new entries other than those that are created whenever new receivers are generated.
<i>It’s now up to 200Mb.</i>
That doesn’t seem very large. However, you might choose to generate a new receiver on a regular basis, then delete older receivers. Ideally, deletion would be after saving them, but that’s probably not necessary. You should probably always keep at least one receiver older than the current one.
The system will normally take care of these receivers when you IPL. If you go for long periods without IPL, you can do some of the cleanup.