Micro Focus Studio Enterprise Edition for Windows > Programming > Mainframe Programming > JCL Support > Files and Data Sets > Data Set Files

Data Set Files

This section contains basic information about using MSS with data sets. For further information on this subject, see the chapter Advanced Data Set Information.

All data sets that are referenced in JCL statements or TSO commands must have an entry in the catalog so that MSS can locate the local file that represents the data set. These data sets include:

Cataloged procedures referenced by EXEC statements
JCL procedures referenced by INCLUDE statements or TSO SUBMIT commands
Input and output data sets referenced in DD statements supported by MSS. See the section JCL Features in the chapter JCL Support for more information.
Input and output data sets referenced in TSO ALLOCATE, FREE and DELETE commands
REXX execs referenced by TSO EXEC commands
Partitioned data sets (libraries) that contain any of the above data sets

Entries in the catalog can be for cataloged or uncataloged data sets. On the mainframe data sets can be fully specified in JCL statements, such that a catalog entry is not needed in order for the operating system to locate them. In MSS, even uncataloged data sets must have entries in the catalog, because the information in the JCL relates to mainframe locations such as volume and serial number, which have no meaning in the Windows or UNIX environment. You can choose whether or not catalog entries for uncataloged data sets are visible when you view the catalog.

Data sets that are not referenced in JCL statements or TSO commands do not need entries in the catalog. For example, if you write a program that accesses a data file that exists only, that program should specify an actual physical filename in its SELECT clause in the Environment Division.

There are three methods of including an entry in the catalog:

New on the Catalog page in ESMAC
Click New on the Catalog page in ESMAC. You need to specify both the MVS name and the local physical filename.
Through the allocation of a new data set (DISP=NEW or DISP=MOD for a new file) by means of a DD statement in a jobstream or an ALLOCATE command in REXX exec. MSS assigns the physical filename.
Dynamically, by MSS, if a data set is used which does not already have an entry. MSS assigns the physical filename.

When MSS assigns the physical filename, it uses the default data file path set on the Properties > JES page of ES Admin, followed by the mainframe name with the extension .dat, For example, if the default path for data files is c:\catalog\datasets then a file with an MVS name of MFE2004.S1217.S160553.J01013.D00006.SYSOUT, will be stored locally as C:\CATALOG\DATASETS\MFE2004.S1217.S160553.J01013.D00006.SYSOUT.DAT

Note: Default behavior is to allow new datasets to be cataloged without specifying a SPACE parameter. If you prefer that JCL missing the SPACE parameter fails in the same way it does on the mainframe, set the MF_NEWSPACE=Y environment variable.