Do we need this crap on LWN? [LWN.net]

Do we need this crap on LWN?

Posted Feb 23, 2007 7:52 UTC (Fri) by drag (subscriber, #31333)
In reply to: Do we need this crap on LWN? by eklitzke
Parent article: ESR's goodbye note

""Also: dpkg cannot install multiple versions of a package simultaneously. RPM can do that, portage can do that, I don't see why this huge feature has been neglected by the Debian community for years.""

I don't understand that and how that works.

In fact it caused major problems for me when I tried to use CentOS that I'd end up with multiple packages installed somehow with no easy way to get rid of them.

Say I have one program that depends on libfoo.3.2 and I have another program that depends on libfoo.3.5 with the libfoo project introducing incompatabilities in their lib files on minor numbers (As many projects do).

Does having multiple packages of libfoo installed automaticly make both programs work? I have no idea.

I mean I've been using Debian for years and I never ever had a desire to install two copies of the same program at the same time...

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Do we need this crap on LWN?

Posted Feb 23, 2007 23:28 UTC (Fri) by eklitzke (subscriber, #36426) [Link]

Normally this is used for things that aren't libraries. For example, you might want to have multiple kernels installed, multiple versions of MySQL, multiple versions of Python, etc. I think if you were careful you could do this with libraries as well, but I'm not sure how intelligent RPM would be wrt overwriting symlinks. As it stands, Debian based distributions include the package version as a component of the package name, to get around the limitation. This is why, for example, on Ubuntu there is currently a python2.4 and python2.5 package. In an RPM based distribution there would just be a bunch of python packages in the same repository, and by default the newest one is installed -- if you need an older version and it is in the repository, it can be pulled in by another package's dependencies, or you can specify the version you want to install at the command line. This is a useful feature, and there are yum extensions (e.g. installonlyn) that use it in interesting and creative ways.