Uncatalogued dataset
A dataset that exists on a disk volume but has no entry in the catalog, so it cannot be found by its name alone.
Also written not catalogued, NOT CATLGD, uncataloged dataset, DEFINE NONVSAM
Normally, when a dataset is created, it is both written to a volume, where the VTOC records it, and added to the catalog, so it can be found by name. An uncatalogued dataset is one that exists on a volume but has no catalog entry.
It can happen in several ways. A job may create a dataset with DISP=(NEW,KEEP) instead of CATLG. Or a job creates a dataset whose name is already in the catalog, pointing at another volume. The new dataset is written, but cannot be catalogued, and the job log shows the message NOT CATLGD 2.
An uncatalogued dataset can still be used, but only by giving its volume in the JCL, with VOL=SER and UNIT. To fix it, you either catalog it, for example with the IDCAMS DEFINE NONVSAM command or the C line command in ISPF 3.4, or delete it, naming its volume.
On SMS-managed storage this is much rarer, because SMS requires every dataset to be catalogued. You will still meet it on older, non-SMS volumes and in old JCL.
Where can I learn this hands-on?
Right here, at ZedBank. You take a junior job at a simulated bank and learn each part of the work by doing it, with Zed beside you. There's nothing to install.
Start at ZedBankRelated
- CatalogThe system's index of where datasets live, so you can refer to a dataset by name without knowing which disk it is on.
- VTOCThe volume table of contents: the list on each disk volume of which datasets it holds and exactly where they are.
- VolumeA single unit of disk storage with a six-character label, on which datasets are placed.
- DispositionThe DISP parameter, which says whether a dataset already exists, and what to do with it when the step ends normally or fails.
- SMSThe Storage Management Subsystem: the z/OS feature that decides where new datasets go and how they are backed up, kept and deleted, using rules the site writes.
- IDCAMSThe utility used to create, list, copy and delete datasets, and the standard tool for anything involving VSAM.