about dataset allocation

kumaresh.M · New User Joined: 17 Feb 2006 Posts: 64 Location: Bangalore

Hi friends,

for creating datasets we can use IEBGENER,IEFBR14 Etc
(we are using somany utilities for creating a dataset through jcl)
i think that if we allocate a dataset through ISPF (3.2 option in ISPF primary menu), defaultly it will create a jcl to allocate a dataset.

my doubt is which utility it defaultly take?
then for example it will take IEFBR14 defaultly,
why the system ignore other utilities?
any other issues is there to select a utilities defaultly?

small_world · New User Joined: 22 Jul 2005 Posts: 24 Location: pune

To allocate or delete a dataset, a program (any program) needs to be executed in a batch environment. But if no other function is needed IBM supplies this program that effectively does nothing.

Example JCL would be :-

//NULL EXEC PGM=IEFBR14
//ALLOCTE DD DSN=MY.NEW.FILE,UNIT=SYSDA,DISP=(NEW,CATLG),
// SPACE=(CYL,(1,1))
//DELOLD DD DSN=MY.OLD.FILE,DISP=(OLD,DELETE)

ofer71 · Posted: Tue Feb 21, 2006 3:01 pm

Utilties does not allocate datasets. The operating system (in forground) or JES (in background) allocate the dataset.

In your job, you instruct the utility to use the dataset, and you supply the disposition. According to the disposition, JES allocates the dataset using operating system services, no matter which program/utility you run.

ISPF options and services use the exact same operating system services to allocate datasets.

O.