I notice my system has area SYSTEM.DDLDCSCR in N/av status. I looked online and CA's examples show it in N/av status too.
I looked to see if it was locked by some process but there is no outstanding lock.
I want to be able to vary it to Retrieval so I can back it up but don't want to mess it up. I also don't want to vary it to Update or Retrieval if it is supposed to be N/av.
Most likely you have specified in your SYSGEN SYSTEM statement, SCRATCH IN STORAGE IS YES and possibly further parameters.
For example I have
SCRATCH IN STORAGE IS YES LOCATION ANY PRIMARY EXTENT 40 MB SECONDARY EXTENT 20 MB LIMIT 60 MB
I do not think any customers have used a DDLDCSCR physical file for many many years, and even if you did, you would never back it up. SCRATCH area is temp work area and is treated as empty at each startup. Nothing from the previous cycle of the CV is available after shutdown/startup.
DCMT D SCRATCH to see what you have defined.
Your scratch area is probably in storage. Look for the SCRATCH IN STORAGE option on your SYSTEM statement in SYSGEN, or do a DCMT D SCR to tell.
If it is, then the SYSTEM.DDLDCSCR area is not actually used and is not brought online. It is only used to size the storage area used for scratch (and even then only if the scratch in storage sizes are not specified on that SCRATCH statement in SYSGEN. If they are, then you don't need a SYSTEM.DDLDCSCR area defined at all).