Do not use JOBCAT or STEPCAT statements in OS/390
In predecessors of todays OS/390 systems, it was not uncommon to use JCL
DD statements specifying user catalogs to be used for a job or a step
(JOBCAT or STEPCAT). This procedure was obsoleted with the advent of the
Integrated Catalog Facility and its ALIAS mechanism, and it should not be
used.
The OS/390 JOBCAT and STEPCAT DD statements when used in jobstreams,
bypass the normal catalog search technique via the ALIAS. Their use can
cause incorrect cataloging of duplicate newdata sets. In addition, these
statements are not supported by Data Facility Systems Managed Storage
(DFSMS). JOBCAT and STEPCAT should not be used when migrating to
OS/390.
5.6.4 OS/390 - VSE/VSAM Catalog Compatibility
Note
Even though (non-concurrent) sharing of VSAM between VSE and OS/390 is
described below, it is recommended that this practice not be extended past
the migration period. As VSAM changes are probable with new releases of
OS/390 DFP or VSE/VSAM, flip floppingof data sets and catalogs between
VSE and OS/390 should be limited to the migration period.
Note that VSAM catalog dates are stored with a two-digit year representation.
Although VSE/VSAM has been updated to interpret these dates using sliding
window technologies, DFP/VSAM has not been changed similarly. DFP/VSAM
use of VSAM catalogs will not function correctly after December 31st 1999.
See the WSC flash article Figure 8 on page 113.
A VSE/VSAM master or user catalog can be designed (DEFINEd) to be
compatible and therefore accessible by an OS/390 system.

Only VSAM user

catalogs may be ported between environments

. For a VSE/VSAM catalog to be
compatible (and used in an OS/390 system), the catalog has to have the
following characteristics:
1. Thecatalog was defined with the IMBED option.
This is the VSE/VSAM default, but many users specify NOIMBED for space
savings within the catalog itself.
2. Thecatalog is on a device supported by OS/390.
Generally, the disk devices not supported by OS/390 are FBA Direct Access
Storage Devices.
Note that non-VSAM data sets within VSAM data spaces, such as
VSE/VSAM-managed SAM files, cannot be accessed in OS/390.
Chapter 5. Disk and Tape Storage Considerations 117