On 7 Oct 2002, Thomas Hood wrote: > In order to decide which version of a package to select, APT assigns a > priority to each available version and selects the version with the > highest priority. If two version have the same priority then the > later one is selected. There are two exceptions to this, however. > First, a version of a package that is earlier than the version that > is installed is never selected if its priority is 1000 or less. > Second, a version of a package is not installed if its priority is > less than 0. [IS THIS CORRECT?]
s/not installed/not available/ All the priority mechanism does is select which version APT/Dselect see as being 'new'. It's possible to make the version (and potentially package) completely vanish with negative priorities. > Package: * > Pin: release v=2.1* > Pin-Priority: 998 > </programlisting></informalexample> > The first word of the default pin specification may be <literal/release/ > or <literal/origin/ (i.e., source). If more than one entry of this kind > appears in the preferences file, only the first one that applies will be > used. This kind of entry can be overridden by an entry that pins a > particular package. [IS THIS TRUE? CLARIFICATION NEEDED HERE.] Hum. You can have as many 'Package: *' entires as you want. The key is that they match entire Package Files, the first one to match a given package file gives it that priority. > <para> > If the Pin-Priority field is omitted then the value defaults to 989. > <para> > Some archives such as the <literal/experimental/ archive are marked > <literal/Not Automatic/ and fall to the bottom of the selection pile. > [DOES THIS MEAN THAT THEY EFFECTIVELY HAVE PRIORITIES OF LESS THAN > 100, OR EFFECTIVE PRIORITIES OF LESS THAN 0?] They are given a priority of 1. > Users of third-party packages such as Helix GNOME can use the pinning > mechanism to force the usage of these packages by setting the priority > of the preferred origin sufficiently high. Helix should probably be changed to the Xiamian or whatever. Is that all of them? Jason
