3 questions on JCL concepts

murali922 · New User Joined: 25 Jul 2005 Posts: 92 Location: India

I am some very intresting questions which I dont the explanation for : -

1. What do you mean by "Sequence Number of a dataset on a tape ?
2. When I code the Volume parameter in the JCL , as a developer how would I know what the volume is ??

For example :

VOL=(,RETAIN,,99),
LABEL=(1,SL,EXPDT=99010),

What does the above statements explain ?? The label parameter and the volume parameters are always confusing for me.

3. What is the difference between Stepcat and Steplib.

I know the basics but not very clear.

Kevin · Active User Joined: 25 Aug 2005 Posts: 234

mmwife · Super Moderator Joined: 30 May 2003 Posts: 1592

1) The "seq# on a tape"... Tapes can contain more than 1 dataset. The "seq#" tells you whether it's the 1st, 2nd, 3rd, etc. The (1,sl... of your example tells you that it's the 1st dataset on a Standard Label (,SL) tape.

2) The VOL=(,RETAIN,99) says, put the DS on any volume(s) up to 99 vols (I think - you can check it) and retain those vol(s) for the extent of the job. You can look at the sysmsg to find the vol sers or you can use listcat or 3.4 of ISPF.

If you used vol=(xxx,yyy,etc...) the system would allocate your DS to those vols.

KavithaPalani · New User Joined: 16 Nov 2005 Posts: 4

STEPLIB - Defines a private library that the system makes available for a use by a job step. The steplib statement can appear in any position among the DD statement for the step and can appear in stream procedures. STEPLIB takes precedence over a JOBLIB

STEPCAT -Define a private VSAM or integrated catalog facility user catalog for the duration of the job step. The system searches the private catalog for the dataset before its searches the master catalog or the private catalog associated with the first qualifier of a data set's name.

sathish_rathinam · New User Joined: 22 Aug 2005 Posts: 59 Location: india

hi murali,

2. u can go for the FILEAID option 3.7 ,which is called VTOC utilty
u get the volume and amount of tracks available ,used and all such details by specifying the datsetname there.....

cheers,
sathish