Re: KDE changing system time
Russell Coker <firstname.lastname@example.org> wrote:
There's a discussion on the OxLug mailing list where people are saying that
KDE messes with the system clock and Debian developers know about this.
What is it?
I've been running the latest Debian/unstable for the last 6 weeks with SE
Linux banning such time changes and my logs indicate that KDE hasn't tried
This is the result the logical fallacy of arguing from the "specific' to
the "general", IMHO. The people who are making such "authoritative"
statements probably started using KDE and noticed the system time was
off about the same time. They connected the dots and began making
proclaimations without much further research.
I have experienced this phenomena long before KDE became a reality! As
it turns out, it is a function of several other factors at the hardware
and OS level.
1. The hardware "clock" on the MB isn't always as stable a reference as
one would assume. Bad design without too much consideration of inherent
drift, and sometimes a failing power source on the BIOS make them poor
time pieces over the long run. If you buy a "cheap" MB, then you
probably are buying a poor timepiece in the bargin. You HAVE to correct
the BIOS settings periodically, just like you have to set your wrist
2. The system clock is run in the OS and is quite different from the
"hardware" clock on the MB. It is a much less stable reference than the
hardware clock and is normally synched with the hardware clock on
bootup. On shutdown the two times are again compared, a drift rate is
computed, and this drift rate is applied to the system clock the next
time the computer is booted. IIRC, heavy disk usage and other OS
functions can cause the system clock to miss a few beats, which
accumulate over time and can cause a highly variable estimate of that
drift rate on shutdown. Things that make heavy use of system resources
will exacerbate this phenomena (KDE, X, large file transferes to & from
the HD, compiling a kernel, graphics, etc.).
3. The longer your computer is "up" the bigger these differences
between the two clocks become, unless corrected periodically. Servers,
routers, and others with long "uptimes" are particularly prone to large
time errors unless corrected.
I could go on into finer details, but you get the idea. We are dealing
with an imperfect time keeping method to begin with, and it is ludicrous
to state/or imply that KDE is the sole cause!
The fix to all this is to synch your computer(s) with an external,
stable time reference. You can do this manually if you want, but it is
quite easy to do it automatically. I have set up one of my LAN
computers as a local time-server that is synched to an external
time-reference and then I synch all my other LAN compters to my local
time server. I have been running this config for over a year, while
using KDE exclusively on all the computers, and I have NEVER had any
problems nor seen "KDE messes with the sytem clock".
I would not place such people in a position of authority....