[lug] Clock Skew

[rm at mamma.varadinet.de]

On Thu, Aug 10, 2000 at 09:12:57PM -0400, John Starkey wrote:
> With all this crazy stuff going in my linux'ized life I got really tired
> of feeling like I'm caught up in a black hole. Not knowing the bounds of
> linux. 
> 
> Soooo. I'm doing my first kernel compile. I wanna step away from the world
> of rpm's. 
> 
> I'm getting a warning right now that says "clock skew detected, build may
> be incomplete." As is consistant with my usual bad timing (and leading to
> confusion) I'm not sure whether this is related to the fact that I changed
> the time in CMOS or it's pertaining to the internal clock speed.

Definitely the first. You probably went back in time ...
'Make' (the tool that you use to build your kernel) looks at 
all the source code files and compares their modification date
with the modification date of the genereated program/kernel.
This is done so that only those parts of a program get recompiled
that depend on files that where changed after the last build.

Now, if you have compiled a kernel (or unpacked the sources) and
then reset your clock 'make' might see files with creation/modification
times in the future. This is what it complains about. Be carefull:
It's usually _not_ a good idea to leave a project like this. Some
files might not get compiled correctly. The easiest fix is to
change to the root of your sources and issue the following command:

 find . | xargs touch

This will set the modification date of all files to the current time.
Of course now all files will be rebuild (after a 'make clean').


 Ralf