Another idea for comments

Emmet Hikory persia at
Sun Jul 29 23:34:26 UTC 2012

Len Ovens wrote:
> However, my concern is that installing from a live dvd/cd has some
> interesting effects on depends. These effects are not very noticeable for
> most flavours of ubuntu because they have one set of software that they
> install not 5 or 6. The install depends on everything, that is in our case
> where in the past graphics items would have depended on the graphics meta
> with the alt install, with the live ubiquity install those apps also
> depend on the install itself. This means, if the user chooses to uninstall
> one of these metas, the meta itself is uninstalled but not the apps that
> should only be dependants of that meta. This has meant that some users
> have uninstalled the apps manually not realizing that one or two of the
> apps might also be a depend for another package (like a font for desktop
> in the case that started me looking at this). These users end up with a
> broken system.

    My understanding is that packages that are installed are marked as
automatically installed unless either 1) the user specifically chose to
install the package, 2) the package is a dependency or recommendation of
a package in Section:metapacakges, or 3) the package is a metapackage
selected at install time.  Removing the dependencies/recommendations of
a metapackage safely requires using apt-mark to indicate that these
are all automatically installed, and using apt-get autoremove to select
the subset of automatically installed packages it is safe to remove.
Documenting this is *hard* (there are manpages, etc., but they aren't
considered very accessible to some hypothetical "average user" who doesn't
want to understand the details of the packaging system).  The reason that
packages that are dependencies of metapackages default to being marked
intentionally installed is that there were persistent complaints in the
past that uninstalling package X (which the user never used nor wanted to
use) would uninstall metapackage Y (because of a dependency relation),
which would then cause half the system to uninstall (because it was the
flavour-defining metapackage).  If there is sufficient interest, it should
be possible to write a tool that allows for clean install/remove of each
workflow, where "install" means "find out which packages are missing,
and install them and their dependencies" and "remove" means "find out
which packages are not needed if only this workflow is missing, and remove
them (and only the unneeded ones)".

> >     Separately from the above, as part of my catch-up reading, I thought
> > there
> > were some threads about merging the live and alternate images.  While I
> Yikes! My first thought is that would greatly increase our ISO size (I was
> thinking double) but it would allow a better install. We do have one of
> the biggest ISOs and doubling it does not leave much room on a DVD... but,
> I think the future of things is to install from usb stick anyway. DVD
> drives are less often included as part of the hardware already, most new
> home video systems also accept USB sticks... I think it is only a matter
> of time before home movies are distributed on a read only memory stick (or
> maybe even with a limited number of plays). Anyway, it will be interesting
> to see where this goes.

    I think there was talk about finding ways to *not* double the size, rather
providing both interfaces for the install from the same set of source data.
Although I don't know the details of the implementation, all the possibilities
I can imagine would imply that there would be more means by which greater
flexibility could be implemented for the Ubuntu Studio install experience.


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