Need the complete explanation of the DEFER Parameter

mmmuthukumar

I need the complete explanation of the DEFER Parameter , In my view - the system waits for the user to mount the device (such as tape) in between the JCL process , but i have so many contradictions , please do explain

8) MMKumar

anuradha · Global Moderator Joined: 06 Jan 2004 Posts: 257

hi MMKumar,

In general this defer parameter is used for tape datasets.the meaning itself says postpone.

if u code UNIT=(TAPE,,DEFER),This can prevent unnecessary mounting of tapes if the job should terminate before the tape dataset is opened.

DEFER may be used to delay a tape mount request until the data set is opened. This avoids a mount request if the data set is never opened. The device allocation occurs at the beginning of the job step, whether DEFER is used or not. This defer option of the unit parameter is helpful when a program does not open the tape or catridge dataset immediately.

hope this may help u little atleast.
others please add.

THANKS AND REGARDS
ANU