Internal operating system usage (OZ 4.6 and newer).
This routine is used by Index to update suspended processes after removal of applications.
OS_Poll, poll for an application
OS_Stk, stack the current process (application)
OS_Ent, enter an application
DC_Ent, enter new application
DC_Nam, name current application
OS_Exit, exit an application
OS_Bye, exit application
DC_Bye, exiting current application
OS_Use, process card usage
DC_Alt, pass an alternative character