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23 October 2009 @ 12:03 pm
XP's clock is weird  
Has anyone ever opened up the "Date and Time properties" dialog (double-click on the time in the the lower right task bar thingy) in Windows XP and just watched the second hand? I swear that every fifth second or so it just pauses for an extra tenth or quarter of a second or so. The clock is staying correct in the long run, so that implies that all the other seconds are actually short by a small but significant percentage. So obviously if it's able to correct everything to come out right in the end it knows how long a second should take, so why not just make it the right length in the first place? I'm very confused.
Current Mood: geekygeeky
受け継がれる意志: Moss-computer :{clock_hasty}:doctorskuld on October 23rd, 2009 08:02 pm (UTC)
It's quite likely that it might be keeping time correctly and in a regular and standard manner but that there is some lag or disconnect between the actual second-hand display of the clock. I wonder if this has anything to do with the refresh rate.
DonAithnendonaithnen on October 23rd, 2009 11:21 pm (UTC)
That pretty much has to be the case, if the internal clock wasn't working correctly i'm sure all kinds of things would be screwed up.

However i'm not sure how refresh rates would affect it either, or at least why they wouldn't have the clock refreshing at a rate fast enough to avoid such frequent and obvious glitches?
受け継がれる意志: Brook-violin :{extremeicons}:doctorskuld on October 23rd, 2009 11:38 pm (UTC)
I guess the rate that the GUI refreshes the information from the BIOS clock just doesn't really match up with real time. I guess Microsoft just figured that nobody would sit there all day staring at their clocks. :p
Kirin: Skuld-computerkirinn on October 24th, 2009 03:09 pm (UTC)
I imagine it's just updating with the normal UI-update loop, the same one that makes sure the correct menu items are checked in synch with internal program states and buttons are enabled/disabled appropriately and so on. That usually gets called a lot less often than, say, a graphics loop that you want at at least 60fps, since UI changes usually aren't that urgent.
Kirin: Skuld-computerkirinn on October 23rd, 2009 08:21 pm (UTC)
Yeah, I'd guess you're seeing an aliasing effect against the refresh rate of the clock dialog - which is essentially the same thing SKuld just said.