The Unit field is incorrect for model 3390-27 and 3390-54 volumes in the display of the DASD command.

Document ID : KB000003893
Last Modified Date : 14/02/2018
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Issue:

The DASD command displays 3390-9 in the Unit column for 3390-27 and 3390-54 volumes.

Environment:
z/OS
Cause:

There is no 3390 model 54 or 27 DASD, it is a model 9 with additional tracks.
The SPace line command shows the number of bytes in the TByt field.
For model 54 the TByt is 5.32G and for model 27 it is 2.74G.

Resolution:

What you see in the Unit field on the display of the DASD command is correct.
SYSVIEW reports these devices as they have been defined by IBM.
The MVS command DEVSERV display also shows these devices as model 9 (33909).
The model 54 or 27 is a concept and not a physical device.

Additional Information:

None