Re: chrony local stratum 10

[Joerg Friedrich <Joerg.Dieter.Friedrich@uni-konstanz.de>]

Saskia Whigham schrieb am Donnerstag, 07. Juli 2005 um 16:00:41 +0200:
> heisst local stratum 10 das chrony oder der Rechner sich mit sich selbst
> syncronisieren soll wenn er keinen Zeit-Server errreichen kann?


aus 'man 8 hwclock':

Clocks in a Linux System
       There are two main clocks in a Linux system:

       The Hardware Clock: This is a clock that runs independently of any con‐
       trol program running in the CPU and even when the  machine  is  powered
       off.

       On  an ISA system, this clock is specified as part of the ISA standard.
       The control program can read or set this clock to a whole  second,  but
       the  control  program  can  also detect the edges of the 1 second clock
       ticks, so the clock actually has virtually infinite precision.

       This clock is commonly called the hardware clock, the real time  clock,
       the  RTC,  the  BIOS clock, and the CMOS clock.  Hardware Clock, in its
       capitalized form, was coined for use by  hwclock  because  all  of  the
       other names are inappropriate to the point of being misleading.

       The System Time: This is the time kept by a clock inside the Linux ker‐
       nel and driven by a timer interrupt.  (On an  ISA  machine,  the  timer
       interrupt  is  part  of  the  ISA standard).  It has meaning only while
       Linux is running on the machine.  The System Time is the number of sec‐
       onds since 00:00:00 January 1, 1970 UTC (or more succinctly, the number
       of seconds since 1969).  The System Time is not an integer, though.  It
       has virtually infinite precision.

       The  System  Time is the time that matters.  The Hardware Clock’s basic
       purpose in a Linux system is to keep time when Linux  is  not  running.
       You initialize the System Time to the time from the Hardware Clock when
       Linux starts up, and then never use the  Hardware  Clock  again.   Note
       that in DOS, for which ISA was designed, the Hardware Clock is the only
       real time clock.




Und um Deine Frage zu beantworten: Wenn kein besserer Zeitserver (kleinerer Stratum)
erreichbar ist, dann benutzt chrony die Hardware Clock, um die
Systemzeit stabil zu halten. Ist allerdings nicht besonders genau :-)

-- 
Jörg Friedrich

There are only 10 types of people:
Those who understand binary and those who don't.