With the z/VSE IPL commands SET ZONEDEF and SET ZONEBDY you can
switch between standard and daylight local times without changing
the IPL startup procedure each time. However, you have to
IPL the system in order to switch to the new time zone,
see the z/VSE System Control Statements for details.
A local time change forward has normally no effect on subsystem
operation. It may have an impact on accounting, however.
A local time change backwards could affect subsystems and
accounting routines more severely.
Therefore I recommend to IPL the z/VSE system for any time changes.