There is a lot of causes!
Take a look here
Thanks for the link, Wilson. I had searched the IBM website but missed that particular entry.
Unfortunately none of the listed update possibilities seem to fit the situation. Users are totally restricted to menus and the library isn’t in any library lists. We have 3 separate application environments (production) with the same base libraries on 3 different LPARs so there’s no possibility of crossover between them. Only one environment has this library but all three environments are working just fine. So I would assume that the only reason that the library is listed in the dsppgmref is due to the fact that it was the library containing the files over which the programs were originally compiled. There are no explicit references to the library in any CLPs so the files are found in the user’s library list at run time. Thus the mystery continues…
The Used date isn’t a save date?
Is it a date when some of the programs were recompiled?
DBU or Easy view could also changes the used date.