synchornize time - w32tm

[Nil]

On 18 May 2010, John Wunderlich wrote in

microsoft.public.windowsxp.general:



> When you do this and, say, Windows notices that it is 2 hours

> slow, it then "speeds up" time so that over the next couple of

> hours Windows will gradually close in on the correct time. You

> will not see the time immediately jump from its current time to

> the correct time. There are programs out there that don't like

> non-contiguous time.



What programs would those be? I've never found any, and I can't imagine

why that would be a problem for anything.



I've never heard of this behavior. Is it documented anywhere? It does

not seem to me to be at all useful, but has the potention to cause much

unnecessary confusion.

 

[John Wunderlich]

Nil wrote in

news:Xns9D7C9EDEA28DFnilch1@130.133.4.11:



> On 18 May 2010, John Wunderlich wrote in

> microsoft.public.windowsxp.general:

>

>> When you do this and, say, Windows notices that it is 2 hours

>> slow, it then "speeds up" time so that over the next couple of

>> hours Windows will gradually close in on the correct time. You

>> will not see the time immediately jump from its current time to

>> the correct time. There are programs out there that don't like

>> non-contiguous time.

>

> What programs would those be? I've never found any, and I can't

> imagine why that would be a problem for anything.



Most of these programs would be archiving and configuration control

programs. If time suddenly jumped backward two hours and a file was

saved shortly after that jump, it may appear, from its timestamp, that

that file was older than a file that was saved earlier in time before

the time jumped backward...





> I've never heard of this behavior. Is it documented anywhere? It

> does not seem to me to be at all useful, but has the potention to

> cause much unnecessary confusion.





Of course it is documented. One place is here:



"How Windows Time Service Works"







.... When the time service has determined which time sample is best,

based on the above criteria, it adjusts the local clock rate to allow

it to converge toward the correct time. If the time difference between

the local clock and the selected accurate time sample (also called the

time skew) is too large to correct by adjusting the local clock rate,

the time service sets the local clock to the correct time. This

adjustment of clock rate or direct clock time change is known as clock

discipline....





HTH,

John