JCL DD Statement for a VSAM Data Set

You can allocate VSAM data sets directly with the access method services ALLOCATE command. The following DD statements demonstrate two additional methods of describing and allocating a VSAM data set:

For allocating and creating a new data set:

//ddname DD DSNAME=dsname,DISP=(NEW,CATLG),RECORG=KS,
//          SPACE=(TRK,10,10),STORCLAS=xxxxx

For allocating an existing data set:
```
//ddname DD DSNAME=dsname,DISP=OLD
```

Access method services does not provide protection for data sets in a shared environment. Therefore, you should use DISP=OLD on the DD statement for any data set that can be accessed improperly in a shared environment.