Example behavior

Use this table to compare and contrast the two levels of VIT control for VIT processing in internal mode.

Action "Base" VIT control "Full" VIT control
Start VTAM® without TRACE,TYPE=VTAM start option.
  • VTAM initializes the VIT with the STDOPTS set of VIT options.
  • DISPLAY TRACE output displays "PSS" as the only active VIT option
  • VTAM initializes the VIT with the STDOPTS set of VIT options.
  • DISPLAY TRACE output displays all seven default VIT options as being active.
Start VTAM with TRACE,TYPE=VTAM,
MODE=INT,OPT=(APIOPTS)
start option.
  • VTAM activates the VIT with all the VIT options defined in the APIOPTS option set, plus the CIO VIT option from the default set.
  • DISPLAY TRACE output displays all the VIT options in the APIOPTS option set as active, but does not display CIO.
  • VTAM activates the VIT with all the VIT options defined in the APIOPTS option set, plus the CIO VIT option from the default set.
  • DISPLAY TRACE output displays all the VIT options in the APIOPTS option set, plus the CIO option, as active.
Start VTAM with TRACE,TYPE=VTAM,
MODE=INT,OPT=(NRM,PIU)
  • VTAM initializes the VIT with the following set of VIT options: API, CIO, MSG, NRM, PIU, SSCP and PSS.
  • DISPLAY TRACE output displays "NRM PIU PSS" as the active VIT options.
  • VTAM initializes the VIT with just the NRM and PIU VIT options.
  • DISPLAY TRACE output displays "NRM PIU" as the active VIT options.
Assuming the STDOPTS VIT options are active by default, issue MODIFY NOTRACE,TYPE=VTAM
,MODE=INT,OPT=(PSS,SSCP,API)
  • Before the MODIFY command, DISPLAY TRACE output indicates only the "PSS" option is active.
  • VTAM turns off the PSS VIT option as part of MODIFY processing, but the SSCP and API options remain active.
  • The output for the MODIFY NOTRACE command indicates that no VIT options are active.
  • Before the MODIFY command, DISPLAY TRACE output indicates all the STDOPTS options as active.
  • VTAM turns off the specified VIT options as part of MODIFY processing.
  • The output for the MODIFY NOTRACE command indicates that "CIO MSG NRM PIU" options are active.
Assuming the STDOPTS VIT options are active by default, issue MODIFY NOTRACE,TYPE=VTAM,
MODE=INT,OPT=ALL
  • Before the MODIFY command, DISPLAY TRACE output indicates only the "PSS" option is active.
  • VTAM turns off the PSS VIT option as part of MODIFY processing, but the remaining default options are unaffected.
  • The output for the MODIFY NOTRACE command indicates that no options are active ("NONE").
  • Before the MODIFY command, DISPLAY TRACE output indicates all the STDOPTS options as active.
  • VTAM turns off all VIT options as part of the MODIFY processing.
  • The output for the MODIFY NOTRACE command indicates that no options are active ("NONE").