Implementing Security for Batch › The Data Lookaside Facility (DLF)

The Data Lookaside Facility (DLF)

The purpose of the Data Lookaside Facility (DLF) is to control the loading of selected data sets into ESA hyperspaces by selected jobs. CA Top Secret can identify and control those data sets and jobs that are eligible for DLF by using a DLF record that is a special or reserved ACID. This record maintains a list of data sets and jobnames that are eligible for DLF processing.

Note: The FDT defines the format of the data on the DLF ACID.

For example, to indicate that data set CICS.MASTER.FILE should be loaded into a hyperspace upon opening, use the syntax shown below.

TSS ADDTO(DLF) DSNAME(CICS.MASTER.FILE)

With this entry, the file will be loaded into a hyperspace when the data set is opened. To indicate that the same data set should be loaded into a hyperspace, but only when opened by the CICS region CICSA (as opposed to any batch job), use this syntax:

TSS ADDTO(DLF) DSNAME(CICS.MASTER.FILE)
               JOBNAME(CICSA)

To indicate that the data set is no longer eligible for DLF processing, use the command shown below.

TSS REMOVE(DLF) DSNAME(CICS.MASTER.FILE)

To tell MVS to leave the data set in hyperspace when the job ends, use the RETAIN keyword. The syntax appears below.

TSS ADDTO(DLF) DSNAME(CICS.MASTER.FILE)
               RETAIN

The RETAIN keyword can be added to an existing entry by specifying the same DSN, and it can also be removed. (RETAIN, like JOBNAME, is an optional keyword.) To grant users access to these data sets, use the DLFCLASS keyword. For example, you might ADD the CICS.MASTER.FILE data set to the OPERDEPT Department using the following command:

TSS ADDTO(OPERDEPT) DLFCLASS(CICS.MASTER.FILE)

You would then PERMIT individual users within that group by using the TSS PERMIT command as shown in the following example.

TSS PERMIT(USER01) DLFCLASS(CICS.MASTER.FILE)

For more information on the Data Lookaside Facility, see the User Guide.