Victor, Ron was correct that unless you have UNIT=AFF, it will always allocate all three drives at initialization time. The reason is that you would never want to be put into a "allocation failure" situation in the middle of a job. If the program can handle being "stopped" half-way through and can then wait for an allocation to become available; then that program should have used dynamic-allocation and actually performed the allocation on an "as needed" basis. But, if the allocation is done with JCL then it will be allocated at initialization time to insure that everything the JCL said was required was available at the time it started.
Russell Witt -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] Behalf Of Victor Zhang Sent: Thursday, August 21, 2008 10:11 PM To: [email protected] Subject: Deferred mount and device allocation Hi experts, One question regarding tape deferred mount and device allocation, supposing following JCL statements: //STEP1 EXEC PGM=ADRDSSU,REGION=6144K //SYSPRINT DD SYSOUT=* //ODOC1 DD DISP=NEW,DSN=TEST1.FILE1, // LABEL=(1,SL),UNIT=VTAPE,RETPD=3,VOL=(,,,255) //ODOC2 DD DISP=NEW,DSN=TEST1.FILE2, // LABEL=(1,SL),UNIT=VTAPE,RETPD=3,VOL=(,,,255) //ODOC3 DD DISP=NEW,DSN=TEST1.FILE3, // LABEL=(1,SL),UNIT=VTAPE,RETPD=3,VOL=(,,,255) Will JES2 try to allocate 3 tape deivces even the datasets are deferred to mount(which is default when using stk vtss)? How to delay device allocation before it is actually be opened? Regards Victor ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
