This job shows you how you can define a page dataset in another master catalog than the currently active master catalog. This technique is typically used when you are building a new system from a driver system. The master catalog referred to via the CATALOG statement below is the to-be master catalog of the new system you are building. //DEFPAGE EXEC PGM=IDCAMS //SYSPRINT DD SYSOUT=* //PAGE2    DD UNIT=3390,VOL=SER=PSYS1B,DISP=OLD //SYSIN    DD *   DEFINE PAGESPACE( -       FILE(PAGE2) -       NAME(SYS1.MVST.PLPA2) -       CYLINDERS(300) -       VOLUME(PSYS1B) ) -     CATALOG(SYS1.MSTRCAT0) /* //Pierre G.