possible. When a synch check is recognized in the TIMEDELTA 0 case, one of the two previously described actions will result. 

## STPZONE {YES | NO} 

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. 

## ACCURACY mmmmm 

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: 

IEA034I THE TOD CLOCK ACCURACY MONITOR IS ACTIVE 

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: 

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. 

## ACCMONINTV mmss | mss 

Sets a timing interval when the ACCURACY function is to be processed The default value is 6000 (60 minutes). 

