Do I need avahi?

[Marko Vojinovic]

On Sun, 28 Jul 2013 17:03:29 +0200
lee <lee at yun.yagibdah.de> wrote:
> Tim <ignored_mailbox at yahoo.com.au> writes:
> > They might not *actually* need it.  i.e. They *may* make use of it
> > for some features, that you *might* use, so they require it for
> > those purposes.  But if you don't use those features, it doesn't
> > need to be running.
> 
> Then why don't packages that don't depend on others but might use them
> simply suggest those packages rather than require them?

What is the actual difference? If package A needs package B in order to
provide some functionality, then it needs it. Otherwise, it doesn't.
Providing package A without B as a dependency will lead to A having
less functionality than it is supposed to have, and that is a bug.

The fact that you might not use or need this functionality doesn't
enter the equation, since someone else might try to use it, only to
find out that it doesn't work --- which would be a clear bug.

So there is no sharp distinction between the dependencies that would
render a package semi-functional versus non-functional. It either works
fully or it doesn't. OTOH, the most famous exception from this design
are the multimedia codecs, but that is just due to legal complications
rather than a design choice.

Nevertheless, I have seen various proposals for RPM to include the
concept of soft dependencies. But AFAIK, it hasn't happened so far.

> When a service is
> disabled, the service should be *disabled* in the sense that it is
> turned off because that's what it usually means.

I suggest that you read this:

   http://0pointer.de/blog/projects/three-levels-of-off

It explains the differences between "stop", "disable" and "mask". Also,
note that it is just a tad bit outdated, since today you can just say

  systemctl mask someservice

rather than making links manually. But the essence is the same.

> Having hundreds or thousands of packages installed that aren't needed
> is not only annoying and a big waste of resources --- everyone needs
> the disk space for them, and it will take bandwidth and time when the
> packages are updated and downloaded by everyone --- it's also a
> security risk.

If you find disk space precious, I suggest that you choose the minimal
install option in anaconda, and after the installation tweak the system
to your needs manually via yum. That way you will have a very clean
system, containing only the stuff you actually need to use, give or
take...

HTH, :-)
Marko