Background:
On NOVA & MiniNOVA platforms VME time is linked in relative terms to the time on the platform TMC (the support computer running on a Windows server).
If this time drifts or is changed then it will cause VME time to drift towards it.
Currently most TMCs have a certain amount of clock inaccuracy (in common with any other server hardware), which will cause VME time to drift.
In addition, from OpenVME 5, there are enhancements to the SET_DATE_AND_TIME command to allow the VME time to be set to the time of an external server (by default the TMC).

The new service:
It has been possible for some time to synchronize the time on the TMC to an external reference (such as a time server on the customer network visible to the TMC) to prevent the time drift problem, however take up of this facility has been minimal.
As part of our policy of continuous improvement, it is intended to proactively link the time of the TMCs to an external reference which, by default, would be via the secure diagnostic link to servers in the Fujitsu Services Support Centre.

Implementation:
This would be rolled out gradually across the installed base, if for some reason you would like this implemented more urgently then please log a call.

1. You will be contacted by a diagnostician to establish that either:
a. You would like the TMC synchronized to an external reference via the diagnostic link (this is only possible when the diagnostic link, be it ISDN or DSL, is left permanently connected for at least outward connections from the TMC).
This is a free service only available to customers with a valid hardware maintenance contract.

The time provided is from an external reference source over which Fujitsu has no control. To the best of our knowledge it is reliable but no firm guarantee can be made about the accuracy of the service provided.

Due to the variations in the time taken to establish the ISDN link, this option may not be available on some non-UK systems.

b. You would like the TMC synchronized to an alternative timeserver accessible on the network and which is already visible to the TMC

c. You would prefer not to have the TMC synchronized and are happy for it to be left free running

2. Once the TMC synchronization has been established it is likely that the TMC time will change. This will have a one-off knock-on effect on VME time which will be drifted slowly to make the two in step again (by however far out the TMC was from UTC). To correct this it will be necessary for the SET_DATE_AND_TIME (STDT) command to be invoked on all the running VME systems/partitions connected to the TMC to either correct the VME time to an absolute value once the clock drift has finished or ideally, on OpenVME 5 or above, to synchronize to the correct time on the TMC.
e.g. STDT(+1:00,S,*) for UK BST, STDT(+0:00,S,*) for UK GMT.
For other time zones the appropriate displacement from UTC/GMT must be supplied in the first parameter as the UTD (Universal Time Displacement) value.
Refer to OptICL for further information.

3. Once the TMC synchronisation has been achieved then it is recommended that a VME call to STDT to synchronise to the TMC is made every reload to correct any discrepancies that might have crept in while the system was being reloaded or powered off. While the system is running automatic synchronization is achieved.

N.B. Daylight saving time on the TMC does NOT automatically reflect through to VME time, it will still be necessary to invoke this with a call to STDT at the appropriate time to change the system UTD.
This will however allow for the exploitation of the clock drift backwards facility when daylight saving time ends during which VME time is slowed for 10 hours to allow the clock to effectively lose 6 minutes an hour and so achieve the 1 hour time correction without having to quiesce the whole system for the hour.

Benefits:
1. Accuracy of VME time in both relative (clock no longer drifting) and absolute (able to set time to an external reference) terms.
2. Exploitation of synchronization facility and ability to end Daylight Saving Time without quiescing the whole system.
3. Minimal costs (unless it is preferred there is no need to provide own time server), the default would be for a daily synchronization over the link so that the ISDN link is not being established too often. If greater accuracy is required this can be increased but it is anticipated that accuracy within a few seconds will be maintained on default settings.
4. Improved accuracy of time stamping on faults reported via the Netdesk software on the TMC.