How will making a group virtual terminal unavailable with TPXOPER affect current users of that VT and when will it become available again?

Document ID : KB000011275
Last Modified Date : 14/02/2018
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Introduction:

I experienced a problem in TPX when selecting an application. It appeared to be related to a previously occurring 0857 sense code error for another user on the GRP VT. My sessions were failing with 0821 errors.
We can get around the problem by manually making the VT unavailable in TPXOPER.

Question:

How will making a group virtual terminal unavailable with TPXOPER affect current users of that VT and when will it become available again?

Environment:
TPX for z/OS
Answer:

For a group (GRP) VT that is marked unavailable, other active sessions will continue to work but no new sessions will be attempted on the VT.

The VT marked unavailable will become available again when either:

  • TPX is recycled, or
  • TPXOPER is used to mark the VT available