S837: End-of-volume error, often too few volumes

What it means

When a sequential data set fills a tape, or input reaches the end of the current volume, end-of-volume (EOV) processing moves the data set to its next volume. To do that, the system needs another volume serial from the DD statement or the catalog, or room in the volume count to ask for a scratch volume. If it can't carry on, it issues message IEC028I and ends the step with system completion code 837.

The return codes are these.

• 837-08 means EOV couldn't find another volume. Every volume serial on the DD was used and the volume count didn't allow more. It can also follow OPEN TYPE=J when the program changed the volume serials, or a label anomaly exit that supplied a volume the system couldn't use.
• 837-04 means the density in the DCB isn't supported by the tape drive.
• 837-0C means the next volume was mounted, but another data set was already using it.
• 837-10 and 837-14 are recording mode problems. The drive doesn't support the mode, or the tape would break the single recording mode rules.

S837 belongs to EOV for any sequential data set, but tape is where you'll usually see it. A disk data set that runs out of room usually gets B37, D37 or E37 instead.

Common causes

• A tape output data set needed more volumes than its volume count allows. Without a volume count, a nonspecific tape request can extend to five volumes, so a file that suddenly needs a sixth fails with 837-08.
• The DD statement lists specific volumes with VOL=SER, and the data needs more volumes than are listed.
• The next volume mounted was still in use by another data set (837-0C).
• A hard-coded density or recording mode doesn't match the allocated drive (837-04, 837-10).

How to find the problem

1. Find IEC028I in the job log. It has the form IEC028I 837-rc,mod,jobname,stepname,ddname,dev,volser,dsname.
2. Count the mount and IEC705I tape-on messages for that DD in the job log to see how many volumes the data set used before it failed.
3. Check the DD statement's VOL parameter for a volume count, which is the fourth value in VOL=(,,,n), and for any VOL=SER list.
4. Compare record counts with earlier runs. A sudden jump in the number of volumes usually means the input grew.

How to fix it

• Give the output DD a volume count large enough for the data, for example VOL=(,,,10), and rerun the step.
• Refer to cataloged data sets by name instead of with a fixed VOL=SER list, so the system knows every volume.
• Use higher-capacity media, a larger block size or tape compaction so the data fits on fewer volumes.
• For 837-04 and 837-10, remove hard-coded density or recording mode settings, or ask for a unit that supports them.

What it looks like

IEC028I 837-08,IFG0554A,PAYRUN01,STEP050,TAPEOUT,0B41,PR4421,PROD.PAYROLL.ARCHIVE
IEA995I SYMPTOM DUMP OUTPUT
  SYSTEM COMPLETION CODE=837  REASON CODE=00000008
IEF450I PAYRUN01 STEP050 - ABEND=S837 U0000 REASON=00000008

Technical reviewer: Albert Joseph, WND Software.

Last reviewed 2026-10-18 by the WND Software team. Written in our own words. For the full reference, check IBM’s z/OS documentation for your release.