Rafeeq ande Mithun, Thank you for the info, which is the kind of thing I like to know.
One of the reasons it is Symantec is that right under the C:\WINDOWS\system32\–ar folder is another folder named {D689B418-235A-4290-A0A5-A75E490E0351} that contains a set of SEP install files.
Then I searched some more in my own files and found exactly what SEP-related activity writes these .DAT files: it is the dbunload command, which is part of database maintenance. .
This is the dbunload command and some of its dialog window output which will illustrate:
C:\Program Files\Symantec\SEPM\ASA\win32>dbunload -c "uid=dba;pwd=xxxxxxxxx" -ar
Adaptive Server Anywhere Unload Utility Version 9.0.2.3654
Unloading "DBA"."BASIC_METADATA" into -ar\436.dat (relative to server)
Unloading "DBA"."SYSTEM_STATE" into -ar\437.dat (relative to server)
Unloading "DBA"."PROCESS_STATE" into -ar\438.dat (relative to server)
etc. etc.
Notice "into -ar" and the filenames which look exactly like what I see in the -ar folder. The files are some sort or work files for the dbunload command.
(I just realized that the dbunload dialog indicates gives a clue as to which table is the largest.)
Knowing this, I have decided to delete the files.
Thank you