gnu linux update question

[Andrew Haley]

On 06/28/2011 04:59 PM, Petrus de Calguarium wrote:
> It is common knowledge that one does not need to reboot for updates to take 
> effect in GNU Linux.
> 
> However, in actual practice, this is not so. I could cite many examples, but 
> this should suffice:
> 
> On Sunday evening, I installed a new updates-testing version of mesa and then I 
> suspended the machine for the night. The following Monday morning (yesterday), 
> I resumed the machine and suspended it again around noon. I again resumed the 
> machine at about suppertime and _powered_ _it_ _down_ about 2 hours later. An 
> hour or two after that, I powered it back up and the mesa testing update turned 
> out to be bad and I was not able to log in. I did not know which program was at 
> fault, because the bad program had been installed over 24 hours prior, but was 
> only showing itself to be bad after a power off.
> 
> Could someone explain how reboots are not needed in Linux for updates to 
> _take_, given the evidence to the contrary.

If a process has a file open and that file is replaced with a new copy,
the process is still using the file handle for the old file.  This is
normal UNIX, nothing new.  How could it be otherwise?

Andrew.