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Re: [tlug] Mandrake vs. Red Hat

On Thu, Jun 06, 2002 at 08:47:07AM +0900, Micheal E Cooper wrote:
> > oversimplified dependency system very frustrating. Whereas Debian
> > dependencies are broken down into 'required', 'recommended', and
> > 'suggested'--now, is that not a much better model of the real world than
> > RPM provides?
> I am not participating in the preference of one system over another because
> I am not yet settled into any system, but I would like to know what a
> 'suggested' dependency is. I thought a software dependency was when one
> piece of software is required for another to run.

In a strict sense, I guess that's true. And that's exactly what you get
with RPM. No more, no less. There is no way for a package maintainer to
distinguish between 'package A requires B in order to run', 'A will work
without B but will only be partially functional', and 'if you use A you
will probably also want B'. Debian's 'required', 'recommended', and
'suggest' represent those 3 relations between packages.

> How are 'recommended' and
> 'suggested' managed? Is this a way of giving the user choices from, say,
> three different packages that can be used to fill a certain dependency?

As indicated above, no, but Debian also has a way to do this. I think
it's called 'virtual packages', one example being 'user-mail-agent' (or
something like that): there are at least 3 MTA packages--exim, sendmail,
and something else--that provide this virtual package, making it very 
easy to change packages without breaking dependencies. Actually, I think
RPM has something similar: certain packages provide certain features
(you can see an example by invoking 'rpm -q --provides' on some
package), but I'm not sure that facility can be used like the Debian
virtual packages. At any rate, I can't recall ever seeing an RPM package
that depended on features without depending on a specific package.

Matt Gushee
Englewood, Colorado, USA

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