HP OpenVMS Systems

VAXELN and TIME; VAX Timekeeping? (TOY, TODR)

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The Question is:

 
This is similar to a question you answered on August 12 - how to you get the
OS to write the time back to the TOY clock.
I'm faced with the same issue on VMS's realtime cousin, VAXELN, which
generates a syntax error for "SET TIME" with no parameters.
 
I realize facility is for VMS questions, but with VAXELN
being such an old product, I doubt there are many places to go for answers.
If you can't answer the question directly, can you point me in the right
direction.
 
In advance, thanks for any assistance you can provide.
 
 

The Answer is :

 
  The Wizard is not particularly familiar with VAXELN.
 
  On OpenVMS VAX, the SET TIME command updates saved time value in the
  SYS.EXE system image.  On VAXELN, as the operating system can run
  diskless, there is not necessarily a corresponding non-volatile
  location where the time value can be stored -- check your VAXELN
  documentation for details on non-volatile storage of time.  This
  value saved in SYS.EXE is then added to the VAX TODR (the Time Of
  Day Register) to determine the current date and time.  The VAX TODR
  has a resolution of roughly 497 days.
 
  The 497 day range of the TODR is the reason that a SET TIME command
  (with no parameters) has to be issued in the first quarter of each
  calendar year, lest the VAX system time be off when the VAX system
  finally reboots -- the saved system time in SYS.EXE needs to be
  updated.  Command procedures such as SHUTDOWN will automatically
  issue the SET TIME command for you.  (Alpha systems do not have this
  particular requirement.)
 
  To determine what sort of TOY (Time Of Year) clock is present on
  the particular system, you will need to check the system processor
  technical documentation -- if available, you would have to access
  this value as the saved time value.  Alternatively, you could consider
  establishing a communications link to a server on a remote system
  (via DECnet or IP) to acquire (and then set) the local system time.
  NTP would be one approach, though simple DECnet task-to-task might
  well be the fastest implementation.
 
  There are examples of setting the VAXELN system time via a DECnet
  communications link available via the customer support center.
 

  

     

     
answer written or last revised on ( 10-NOV-1998 )
     
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