As has been talked about, that's an old way of coding practice. One of them is known as "class indicator" and other is "Label".
Class Indicator: The Class Indicator can be and have the following meanings:
UR = Unit Record - card reader, card punch, printer
UT = Utility - Tape or Disk or Drum or Cell (note: if UT and Disk or Tape, organization must be S)
DA = Direct Access - Disk, Drum or Cell (note: organization indicator must be I or D).
Check this see
http://publib.boulder.ibm.com/cgi-bin/b ... 05/4.2.3.1 to see what is not "meaningful" in currently supported IBM mainframe compilers on OS/390, z/OS, or VM environment.
More than "old days" ago there were disk drives and tapes were "utility devices". Concept of a
utility-device changed when the first 2311s arrived, but COBOL supported either tape or disk as 'Utility'.
"DA" was for "Direct Access" and that meant "non-sequential" and therefore could NOT be a UTILITY device. The "UR" meant "Unit Record" which really meant "unblocked" (early printers and punch card readers/punches accepted a single "record"). It was only later when we started spooling print to disk that print files became "blocked", but COBOL still allowed them to be treated as "unit record" (as it does to this day... I think I'm correct here?).
To summarize it all, for theory, - DA (mass storage); UT (utility) and UR (unit-record).
Label: Was used to documents the device and device class to which a file is assigned. With modern compilers it's not required but if specified, it must end with a hyphen. It can have the following meanings:
S- for QSAM files, the
S- (organization) field can be omitted.
AS- for VSAM sequential files, the
AS- (organization) field must be specified.
For VSAM indexed and relative files, the organization field must be omitted. So it's not used.
Hope this helps.