What does the following apt-get response mean?

[John Conover]

Dotan Cohen writes:
> On Wed, Dec 1, 2010 at 09:14, John Conover <conover at rahul.net> wrote:
> >
> > What does the following apt-get response mean?
> >
> >    root at mymachine:/ 520# apt-get upgrade
> >    Reading package lists... Done
> >    Building dependency tree
> >    Reading state information... Done
> >    The following packages have been kept back:
> >      linux-generic linux-headers-generic linux-image-generic
> >    0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
> >
> > Why won't it upgrade it?
> >
> 
> Try using dist-upgrade instead.
>

Thanks, Dotan. That worked. What caused it to not upgrade?

I have three machines that are all identical, but one would not
upgrade. Do you know what caused it?

Should "dist-upgrade" be used, always, instead of just "upgrade"?

    Thanks,

    John

-- 

John Conover, conover at rahul.net, http://www.johncon.com/