Autosignoff (ASOT)

Autosignoff deallocates users from an idle session. If no activity occurs on a session within an allotted time, users are automatically signed off and must sign on again in order to use the session.

The system programmer sets the autosignoff time using the ASOT parameter in the DFSPByyy member. The time value on the ASOT EXEC parameter does not apply to 3600, SLU P, or ISC devices.

If more than one allotted time value exists, IMS uses the following criteria to determine which allotted time value to use:
  • If the valid ASOT value is specified in the user descriptor, this allotted time value is used.
  • If the user descriptor does not specify an allotted time value, the allotted time value from the logon descriptor is used.
  • If the logon descriptor does not specify an allotted time value, the time value from the DFSPByyy member is used.
  • If the DFSPByyy member does not specify an allotted time value, the default value of 1440 is used.
  • If the value on the DFSPByyy member is not valid, the default value of 10 is used.

The Logon exit routine (DFSLGNX0) can override the ASOT and ALOT values during logon. The Signon exit routine (DFSSGNX0) can override the ASOT value during signon, even when the control block structure exists.

The values for the allotted time specified on the ASOT parameter in the DFSPByyy member are:
  • ASOT = 0
    • The user is signed-off immediately when no output is available to be sent. This specification is normally used with Autologon terminals for signoff immediately when:
      • No IMS input or output message is available
      • After the last available output message completes
    • This specification is not recommended for interactive terminals such as 3270 or SLU2 terminals. These terminals sessions normally return a PA key to continue following signon. Idle time results in immediate signoff, not waiting for terminal input.
    The value on the DFSPByyy member is not used for these device types.
  • ASOT = (10 - 1439)
    • The user is signed off after the allotted number of minutes has elapsed without terminal activity.
  • ASOT = 1440
    • The user is never automatically signed off. This is equivalent to not having autosignoff. The system default value for SLU-P, 3600/Finance, and ISC terminals is 1440.

After autosignoff completes, IMS attempts to locate a user that has the same node name that is waiting for autologon. If IMS finds another user with output waiting, the user is allocated to the terminal, and the queues are drained.