[Pharo-project] System time

Mariano Martinez Peck marianopeck at gmail.com
Sun May 1 14:56:49 CEST 2011


On Sun, May 1, 2011 at 4:15 AM, Jimmie Houchin <jlhouchin at gmail.com> wrote:

> Hello,
>
> My OS for this application is Windows. On a freshly opened image, the image
> and OS time are in sync. Over a period of time the image drifted 34 seconds
> away from OS time. I do not know how long I had this image open, but it has
> been a number of days, possibly a week plus.
>
> I saved the image and quit. I reopened the image and did DateAndTime now
> and it was in sync with the OS once again. Same image, vm and OS that was
> out of sync by 34 seconds only one minute before.
>
> I have opened an image on my server which is also running the latest cog
> vm, the current Pharo 1.3 and Windows Vista. I am going to periodically do a
> DateAndTime now to log the drift if any. Prior to opening this image I
> updated the OS system clock with time.nist.gov which is about 1000 miles
> away.
>
> I know that within a second or so it can be subject to my coordination of
> doing DateAndTime now while watching my OS system clocks seconds. But 34
> seconds is beyond any subjective standards.
>
> The only reason I discovered this was while exploring how I want to
> retrieve my data, act upon my data and then pause (Delay wait) until time to
> repeat.
>    dtnow := DateAndTime now.
>    dtnext := DateAndTime year: 2011 month: 4 day: 30 hour: 11 minute: i
> second: 5.   "The next minute in the future"
>    (Delay forDuration: (dtnext - dtnow)) wait.
>

I have no idea about these topics...but maybe something related to the Delay
issue that Gary and Andrian used to have:
http://code.google.com/p/pharo/issues/detail?id=3986



>
> I got an error, that Duration cannot be a negative number. As I processed
> the debugger, I saw that dtnow was greater than dtnext. I watched the OS
> clock and manually selected the next minute before I executed. However, I
> was within that 34 second window.
>
> So now I am exploring the problem.
>
> Thanks.
>
> Jimmie
>
>
> On 4/30/2011 5:06 PM, Alexandre Bergel wrote:
>
>> 'Time now' gives me the same result than OSX
>>
>> Alexandre
>>
>>
>> On 30 Apr 2011, at 16:15, Jimmie Houchin wrote:
>>
>>  On 4/30/2011 11:50 AM, Stéphane Ducasse wrote:
>>>
>>>> I am developing a time sensitive application. I poll a server every
>>>>> minute for new data. The data is time sensitive and the sooner I can get the
>>>>> data to the release of the data the better.
>>>>>
>>>>> I have noticed that Pharo's system time drifts away from the OS system
>>>>> time. I would really like the Pharo system time to be the correct time.
>>>>>
>>>> do you have a repeatable scenario?
>>>> VM
>>>> Image information.
>>>>
>>> Pharo 1.3 and the latest Cog.
>>>
>>>  I have not been able to find where in Pharo I can call to update the
>>>>> System clock to the correct time.
>>>>>
>>>> you can use OSProcess (only mac and linux)
>>>>
>>> No, that's not the problem. The OS clock is right. It's Pharo that has
>>> drifted away from correct time. Regardless it would be nice if I have to
>>> correct the OS clock, it would still be nice to resync Pharo with the OS,
>>> keep both in sync and correct. What I am wanting is simply to resync the
>>> Pharo clock with the OS clock.
>>>
>>> It seems that when the Pharo image is started that it gets the OS System
>>> time, but keeps its own time after that. Now I do not know the consequences
>>> of Pharo adjusting its time backward. If this isn't possible, then I might
>>> have to do some workarounds to insure that I get my data in a timely manner.
>>>
>>> The image I have been developing in is currently about 30 seconds ahead
>>> of the OS clock. It is on my laptop. It might be due to the laptops sleep
>>> and hibernation. I have not tested this on my server.
>>>
>>> That is the situation as best I know it.
>>>
>>> Thanks.
>>>
>>> Jimmie
>>>
>>>
>
>


-- 
Mariano
http://marianopeck.wordpress.com
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