Methods to Use the REXX LISTDSI Perform to Get z/OS Dataset Info Rapidly and Simply

Mainframe programmers are problem-solvers. In at this time’s massive, advanced information facilities, we’re typically confronted with ad-hoc questions from administration – questions that echo the outdated Nationwide Enquirer slogan, “Inquiring Minds Need to Know.” And administration normally desires solutions proper now:

• What does this dataset appear like?
• What are its traits?
• How a lot area does it occupy?
• When was it created and final referenced?

For a single dataset, this kind of data can normally be obtained with a look at an ISPF panel or two. For a listing of datasets, although, it’s not so easy. We have to get hold of detailed information for every dataset, presumably maintain observe of operating totals, and supply a report.

Why REXX and LISTDSI Are a Pure Match

The REXX programming language is right for fixing these types of issues, and the REXX LISTDSI operate permits the programmer to simply get hold of all types of details about a z/OS dataset.

LISTDSI returns information in nicely over 30 variables that may inform us the whole lot from the dataset’s group and file size to its encryption key label, variety of listing blocks, and SMS class names.

When utilized in a loop to learn an enter record of dataset names, LISTDSI variables like SYSALLOC and SYSUSED will be collected to maintain a operating whole of disk area. Different variables, like SYSEXPIRE and SYSUPDATED, can be utilized to establish potential issues – for instance, disk datasets which have expired or have been modified however not backed up.

Operating LISTDSI in TSO or Batch

LISTDSI is a TSO/E exterior operate and should run in a TSO handle area. That is normally not an issue, nevertheless, because it’s doable to run TSO in batch just by specifying PGM=IKJEFT01.

The best format of LISTDSI is just a REXX operate specifying the dataset title, for instance:

x = LISTDSI(the-dataset)

the place ‘the-dataset’ is a variable containing the one dataset title for which we would like data.

The variable ‘x’, the operate code, is critical as a result of LISTDSI have to be referred to as as a REXX operate. A zero operate code signifies success, 4 signifies partial success (some however not all information returned), and 16 signifies a failure.

The precise dataset data is positioned in quite a few predefined REXX variables, all of which start with the characters ‘SYS’ – similar to SYSVOLUME, SYSDSORG, SYSRECFM, and so forth. The contents of those variables can then be written out utilizing REXX ‘SAY’ statements or used for different processing within the exec.

Optionally available Parameters That Return Even Extra Element

By default, LISTDSI merely obtains details about the dataset from the catalog and the quantity VTOC. Nevertheless, a number of extra parameters can observe the dataset title within the LISTDSI name to return additional data, together with listing block counts and SMS class names.

Crucial of those parameters are:

• RECALL/NORECALL, which controls whether or not DFSMShsm is allowed to recall datasets from archive throughout LISTDSI processing
• SMSINFO/NOSMSINFO, which returns the category names for SMS-managed datasets.

Recognized Limitations to Be Conscious Of

There are, sadly, nonetheless a couple of limitations to LISTDSI processing.

No data is returned for tape or Unix Techniques Companies information, and technology dataset names have to be totally specified (no relative GDGs). For VSAM datasets, solely a restricted subset of data is returned (SYSVOLUME, SYSUNIT, and SYSDSORG).

It’s doable these drawbacks might be eliminated in a future z/OS launch. Even with these limitations, nevertheless, LISTDSI is an awfully easy strategy to get detailed details about z/OS datasets.

That data is returned in easy-to-use REXX variables, and supplies a fast approach for the programmer – going through a sudden demand for information – to offer what’s wanted, when it’s wanted, to fulfill these inquiring managerial minds.

Instance: Displaying Key LISTDSI Variables

The determine beneath reveals a easy REXX exec that shows among the extra fascinating LISTDSI variables for a specified dataset title, together with the date and time the dataset was created:

Turning LISTDSI Output into Operational Perception

LISTDSI provides mainframe groups a quick, versatile strategy to extract important dataset particulars utilizing acquainted REXX constructs – making it simpler to reply questions, spot points, and maintain storage data flowing when it issues most.

To go even additional and acquire deeper visibility, automation, and management throughout your storage surroundings, be taught extra about how Syncsort Storage Administration helps simplify and optimize z/OS storage operations.

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