Mainframe BackUp?

[bazzigar]

Hello,

RASP914F DD DISP=(,KEEP,KEEP),LABEL=(002,SL),UNIT=AFF=RASP914E,
VOL=(,RETAIN,REF=*.RASP914E),
DCB=SYS2.DUMDCBL,DSN=SYSX.BACKUPRA.SP914F.SITE4


Could someone explain what is
1: UNIT=AFF=RASP914E
2: VOL=(,RETAIN,REF=*.RASP914E)
3:DCB=SYS2.DUMDCBL

from the above DD Statement.
I know the purpose of all the above parameters but no idea about the code here.

Thanks,

[expat]

Obviously you have not bothered to read the JCL manual for the UNIT= sub parameter

[Robert Sample]

All three of the parameters are clearly explained in the JCL manuals. As an example, section 12.62.2 of the JCL Reference manual on the UNIT parameter has

AFF=ddname
Requests that the system allocate different data sets residing on different, removable volumes to the same device during execution of the step. This request is called unit affinity, where "ddname" is the ddname of an earlier DD statement in the same step. Use unit affinity to reduce the number of devices used in a job step; request that an existing data set be assigned to the same device(s) as another existing data set.

If you specify the UNIT=AFF subparameter for system-managed DASD, the system ignores it. If you specify the UNIT=AFF subparameter for system-managed tape libraries, the system attempts to honor it.

Under certain conditions the system ignores unit affinity. See z/OS MVS JCL User's Guide for more information.

In a JES3 environment, UNIT=AFF=ddname may not be honored. See z/OS MVS JCL User's Guide and z/OS HCD Planning for information about device eligibility and unit affinity.

After reading this manual explanation, what do you not understand about UNIT=AFF=RASP914E? Your other two questions are left for you to find and read the manual yourself.