Dataset properties given in jcl

Dataset properties given in jcl:

Data properties we can in jcl by using DISP command
the syntax of disp is
   Disp= (status, Abnormal termination, normal termination)

  in disp in status we can give 4 options they are
       1)New--->to Create a new data set
       2)Shr  --->to read the data from data set
       3)Old---->to write the data to data set
       4)Mod--->to Append the data to data set

in Normal termination give the properties as
      1)catalog
      2)delete
      3)un catalog
      4)keep
      5)pass

in Abnormal termination we can give properties as
      1)catalog
      2)un catalog
      3)keep
      4)pass

what is difference between catalog and UN catalog?


   if u give catalog it will store in some volume. so it is easy to retrieve
   in un catalog the data set will store in unknown volume. so it is hard to retrieve. .