You can view and update some entries in the JES catalog from the ESMAC interface; however, ESMAC does not provide full access to the information stored in the catalog. The Public Catalog API enables you to access and update the information in the JES catalog, including information that is not available from the ESMAC interface.
You can gain full access to the information in the catalog by calling the API from a COBOL program. When you run the program in Enterprise Server, you can access and update the information in the catalog. When the API is called while under the control of Enterprise Server it enques and deques on datasets, preventing catalog entries from being updated while in use elsewhere. However, no such security is available when you run a program outside of Enterprise Server. Therefore, when you run a program outside of Enterprise Server, you can access information in the catalog, but you cannot make any updates.