distributions

[darose-prQxUZoa2zOsTnJN9+BGXg at public.gmane.org (David Rosenstrauch)]

Tom Metro wrote:
> Do you compile packages locally with Arch as you do with Gentoo?


You can, but generally don't.  (i.e., only if you have a specific need to.)


> If not, then how does it handle library version skew?


?  Not sure I understand what that phrase means.


>> In practice, you just keep upgrading individual packages.  Sometimes 
>> when the upgrades are major (e.g., when upgrading kernel, xorg, kde, 
>> gnome, etc.) you run into some headaches, but mostly not. 
> 
> That sounds pretty close to Ubuntu. Unlike Debian, they do upgrade some
> packages between releases (Debian stable only provides security
> updates), and new releases pretty much always include a newer kernel, X,
> GNOME, etc.


Given that you're saying that Ubuntu does do some package upgrades
between releases, then I guess there's some similarity.  But again, it's
different from Ubuntu and the others in that there's no real "version"
of the distro that you "upgrade" to.


>> And at least you don't run into a whole bunch of package upgrade
>> headaches all at once, as you would when upgrading to a new version
>> of a distro.
> 
> I run into distribution upgrade headaches with Debian and Ubuntu, though
> despite many dozens of packages being updated simultaneously, typically
> only one or two poses a problem.


Sounds like you're amongst the lucky then.  From what I read on the
mailing lists, it seems like distro upgrades cause a lot of grief re:
things like kernel modules, wireless, X, etc.


> For the most part a distribution
> upgrade is just a bit inconvenient due to the time required to merge
> local config changes into the stock config files.


Another advantage of not having to do a "distro upgrade" then.  You only
need to merge a small number of config file changes with each upgrade.


> In theory, with a distribution like Arch, if any package can be at any
> version, that creates a pretty huge set of permutations such that no two
> Arch systems will be anywhere close to identical. So if something
> breaks, what are the chances that someone else is running the same set
> of packages you are?


That's not at all the way it works.  Read on.


> It sounds like in practice this hasn't been a problem, but one of the
> big points to having a defined release is that it can be tested as a whole.
> 
> Perhaps this works for Arch because the majority of users keep all their
> packages updated to the latest versions, and that rolling target is what
> package maintainers test against. Of course that starts to fall apart if
> you have a lot of package maintainers all working independently.
> 
>  -Tom


Yes, at any given point in time, the distro's main repo officially
supports only one specific version of any package.  Everyone retrieves
that version from the distro's repo using their package manager, so
everyone is generally running the exact same versions of the various
software packages.  (You can of course upgrade/downgrade to different
versions locally if you want, but you're on your own when it comes to
bugs & incompatibilities.)

The distro's developers and package maintainers are tasked with
upgrading the packages to newer versions, and although they tend to keep
*very* up to date with upstream source code, they won't just roll out a
new version willy nilly.  The package maintainer is responsible for
testing out the new version (sometimes assisted by users who are willing
to use the testing repo), and resolving incompatibilities, and will
often hold the upgrade until major issues get worked out.

This isn't perfect, of course - when you're using bleeding edge packages
there's bound to be problems from time to time - but a) that's part of
life on the bleeding edge, and users who choose to run Arch know this
going in, and b) the devs and the (rather active) userbase all do a
pretty good job of chipping in on filing bugs fixes, posting solutions
to mailing lists, and submitting patches.

Arch is a really nice distro.  It kind of combines some of the best
qualities of Debian and Gentoo.  It's not for noobs, but if you're the
kind of Linux user that doesn't mind editing config files from the
command line, it provides a lot of power in a very elegant package.

DR