Mainframe, MVS and zOS Discussion

Hi,

In our system we have many type of datasets. Datasets starts with different names, like some datasets start with 'T', others with 'P' or 'W'. Now how does system decides which unit parameter should be used for which qualifier? I thought it should be done by CLASS but the links I read through did not make it very clear to me. Like this document:

https://www.ibm.com/docs/en/zos/2.2.0?t ... cteristics :: but it does not tell anything about unit and high level qualifier of the datasets.

Nor this :: https://www.ibm.com/docs/en/zos/2.1.0?t ... -parameter

Could someone please guide.

ACS routines of DFSMS takes care about it. DFSMS is Data Facility Storage Management Subsystem.

I thought it should be done by CLASS

Job class determines which system(s) the job can execute on -- which may, indirectly, have an impact on where the dataset is placed. The SMS ACS routine usually makes the final determination.