8480ch02.fm Draft Document for Review January 6, 2020 11:24 pm possible. When a synch check is recognized in the TIMEDELTA 0 case, one of the two  previously described actions will result.  This specifies whether the system image is to get the time zone constant from the STP. The  time zone constant specifies the difference between the local time and the UTC. The default  is YES, when also STPMODE is set to YES. The z/OS TOD clock accuracy monitor was introduced with z/OS V2.1 to monitor the  accuracy to which a CTN is synchronized with an external time source (ETS). The  ACCURACY statement in the CLOCKxx PARMLIB member specifies a threshold for the time  deviation between the UTC time of the CTN and an external time source. The accuracy  monitor checks the deviation and issues a message if found to exceed the specified  ACCURACY threshold. The z/OS TOD clock accuracy monitor is enabled by specifying a non-zero value between 0  and 60000 milliseconds (60 seconds) for the ACCURACY parameter in the CLOCKxx  PARMLIB member. The default value for ACCURACY is zero, meaning that the accuracy  monitor is disabled When CLOCKxx is processed at IPL time, and a non-zero value is  specified for the ACCURACY parameter for a system running on an STP network that is  synchronizing to an external time source, the ACCURACY function is activated. This results in  the following IPL-time message: The monitor will then check the time deviation every 60 minutes unless the ACCMONINTV  keyword is specified with a user-defined timing interval. If the TOD clock exceeds +/- the  ACCURACY value, the following message is issued and then reissued every 60 minutes until  the condition is corrected: STPZONE {YES | NO} ACCURACY mmmmm IEA034I THE TOD CLOCK ACCURACY MONITOR IS ACTIVE IEA032E TOD CLOCK ACCURACY LIMITS MAY HAVE BEEN EXCEEDED When the time difference is corrected the following message is issued: IEA033I THE TOD CLOCK IS NOW WITHIN SPECIFIED ACCURACY BOUNDS Note:  IBM recommends that ACCURACY be set to 20 for customers that need to meet the  FINRA clock synchronization requirement. This will cause IEA032E to be issued when the  steering adjustment exceeds 20 milliseconds. To help customers meet the FINRA clock synchronization audit requirement, new function  have been added to the z/OS accuracy monitor via APAR OA51786. A message is issued  at a user specified interval, with a default of every 60 minutes, giving details of the current  status from the PRT correction steering information block.  See also the discussion about the FINRA requirements in 1.1.3, “Industry requirements”  on page 4 and in 2.3.2, “NTP server with pulse per second” on page 40. Sets a timing interval when the ACCURACY function is to be processed The default value is  6000 (60 minutes). ACCMONINTV mmss | mss Chapter 2. Planning hardware and software  49