On 2014-12-10 17:48, Charles Mills wrote: > > Question: Does the use of aliases make sense? Let's say HLQ.BAR is identical > across A, B and C. Should I make one HLQ.BAR.COMMON and alias it as .A, .B > and .C? Or is that overkill for a simple one-person situation? Should I just > make three identical PDSes and not over-complicate the problem? > > Disk space is not the issue -- these are relatively small datasets. I guess > it just bothers my engineering desire for elegance to have three identical > datasets when I could have three pointers to one dataset. I guess "not > mucking up the maintenance" -- changing one and failing to change the others > -- is also a possible concern. > We use aliases with almost an opposite objective: During development, we will build to, e.g., HLQ.Dyymmdd.LINKLIB, then relate alias HLQ.CURRENT.LINKLIB to the newest of those so our testers needn't change JCL members chasing data set names. (I suppose JCL INCLUDE members would work as well, perhaps even better, but that's too innovative for some of us.)
Caveats: o The HLQs must be the same, or at least in the same usercat, else catlog lookup will never find the related data set. I think this is an incredibly dumb rule, saving only one lookup in the master catalog, but my colleagues steeped in the MVS culture find it natural. o You can't have an alias of an alias. I think this is an incredibly dumb rule, saving the overhead of recursive lookups in the master catalog, but my colleagues steeped in the MVS culture find it natural. o At job initiation, the initiator ENQs on the alias name. At allocation it ENQs on the related DSN. If there's an ENQ conflict at that point, the job terminates with a JCL error. What else might a simple-minded initiator do. (JES2; I don't know if JES3 behaves otherwise.) o AFAICT, no ENQ ever precludes IDCAMS DEFINE ALIAS or DELETE ALIAS. Il a les défauts de ses qualités. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
