On Fri, 15 Oct 2010 22:17:43 +0200 Achim Scheidl <AchimRS@gmx.de> wrote: > > Essential only means that > > packages which depend on an Essential package do not (indeed should > > not) specify a dependency on those packages > > So the packages depending on one of these essential packages assume > that they are installed. They uses some functionality within an > essential package and fail if it is not available. This is an inherent weakness in current Debian. It would be better if there was a different mechanism for this but in most cases, you can assume that a shell and utilities like coreutils, sed, awk, grep and mount will be needed as well as the Debian core packages like dpkg. The full list is always available on any Debian machine by running: $ grep-available -FEssential 'yes' -sPackage (This will only work on a machine with Debian sources - any machine with only Emdebian apt sources will return an empty list.) > And that is what I experience in my system: Some packages don't work > or throw cryptic error messages and after some analysis it came out > that a package is missed. That is more likely to be a missing Recommends. Emdebian drops those too, principally because they are optional dependencies. i.e most of the functionality of the package is fine. There is no getting away from the reality - having a smaller Debian means that users have to do some work to ensure that you get a fully working package set. If you want the full hand-holding of Essential and Recommends, you will end up with packages you don't actually use. In this case, convenience is the enemy of capacity - specifically storage capacity. Making Debian smaller means making work for yourself because you are second-guessing the automation built into Debian. > Once I found the missed package I see it's > classified as "essential", which (with my brand new knowledge:-) > explains why it was not within the dependency chain ... > > Now I understand this Essential classification as "required for > installation of other packages". More like "undeclared dependencies which Debian normally expects you to have around" - but which Emdebian allows you to *not* have around at your own risk. > Hmm, than we lost the information about which packages are in this > group of implicit referred essential packages. See above. > > grep-available -FPriority 'required' -sPackage > > > > This gives you a full list of Priority: required packages but you > > won't necessarily need all of them. > > > I've tried this on my Emdebian installation, but it only shows the > Priority: required packages within the packages I've already > installed. That one missed on my system are still not shown :-( As ever, for the full list, run the command on a Debian box. Emdebian filters lots of things, including the package lists. Alternatively, create a temporary Debian apt source, run apt-get update, run the command, remove the temporary apt source and run apt-get update again. Be specific - which package was not working and which package was missing? > Is there some command or web-site fetching the information out of the > online package repository? packages.debian.org will list Recommends: and the link from that page to the packages.qa.debian.org page for the same package will show the Priority information but not whether a package is Essential. I might get around to making a link from our Emdebian package search page to the relevant Debian package view because then things like Recommends: become obvious. If you fancy writing a script (using the core bits of apt support in xapt or multistrap) to download the Debian data to a temporary location, run the test and delete the temporary data, you're welcome to do so and we can see about adding it to one of the Emdebian packages. I've been thinking of an emdebian-goodies source package for a while, based on the idea of debian-goodies and devscripts. There are a variety of little scripts hanging around which don't need to be in their current packages but are too small for their own packages. -- Neil Williams ============= http://www.data-freedom.org/ http://www.linux.codehelp.co.uk/ http://e-mail.is-not-s.ms/
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