----- Original Message ----- From: "Rowel Atienza" <[EMAIL PROTECTED]> To: "Philippine Linux Users Group Mailing List" <[EMAIL PROTECTED]> Sent: Thursday, November 18, 2004 5:53 PM Subject: Re: [plug] linux uptime
> > as you can see, uptime has > > nothing to do > > with the hardware clock nor with the system clock... > > > > Not really since both wall time and uptime are updated by timer > interrupt handler driven by the system timer. jiffies and timer_jiffies are incremented by the timer interrupt handler and wall_jiffies (used by wall time) depends on the jiffies and timer_jiffies variables.... uptime is just depending on the value of jiffies divided by HZ... therefore changing the value of hardware clock or the system clock has nothing to do with the uptime as what the previous poster is asking about... > The wall time is in fact periodically saved to hardware clock or > RTC at a periodic rate approx equal to 11 mins. This is implemented by > set_rtc_mmss() of do_timer_interrupt() in arch/i386/kernel/time.c . otherwise known as 11 minute mode in linux... this is only true if the kernel time is synchronized with an external source (eg. via xntpd because it turns it ON the 11 minute mode) because hardware clock is usually not very accurate... this is called systematic drift... but still it has nothing to do with the uptime... fooler. -- Philippine Linux Users' Group (PLUG) Mailing List [EMAIL PROTECTED] (#PLUG @ irc.free.net.ph) Official Website: http://plug.linux.org.ph Searchable Archives: http://marc.free.net.ph . To leave, go to http://lists.q-linux.com/mailman/listinfo/plug . Are you a Linux newbie? To join the newbie list, go to http://lists.q-linux.com/mailman/listinfo/ph-linux-newbie
