[ntp:questions] Start of new GPS 1024 week epoch

Martin Burnicki martin.burnicki at meinberg.de
Fri Aug 23 10:52:38 UTC 2013

David Taylor wrote:
> On 20/08/2013 13:25, Martin Burnicki wrote:
> []
>> There were 2 fields in the SHM segment which were previously unused and
>> are now used to take the nanoseconds from the refclock and from the
>> system time.
>> Thus programs like gpsd can now write the nanoseconds in addition to the
>> microseconds. If there's an old version of ntpd running then it just
>> evaluates the microseconds, but new versions (ntp-dev for now) check if
>> the nanoseconds fields are filled up and use them if this is the case.
>> Thus an old ntpd works with a new gpsd, and a new ntpd works with an old
>> gpsd. See:
>> Bug 1232 - nanosecond support in SHM driver
>> https://bugs.ntp.org/show_bug.cgi?id=1232
>> Martin
> Is SHM supported on Windows?  I know that it /could/ be as the
> mechanisms exist within the OS, but /is/ it?

I'm afraid it is not.

A quick look into the config file for Windows for the current ntp-dev 
version shows that support for the SHM driver is commented out.

I have also worked with shared memory under Windwos for the driver 
software for our PCI cards, Windows uses completely other API calls for 
the shared memory support, and thus "someone" needed to port the SHM 
driver in ntpd to Windows first.

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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