Current situation of amarok, and of latex tools
christopher.chan at bradbury.edu.hk
Mon May 25 02:36:12 UTC 2009
Christopher James Halse Rogers wrote:
> On Mon, 2009-05-25 at 03:03 +0100, Dmitrijs Ledkovs wrote:
>> 2009/5/25 Christopher James Halse Rogers <raof at ubuntu.com>:
>>> Having some sort of "roll back to previous package version" button might
>>> be a nice idea, though it would need to be designed in such a way that
>>> made it clear there was no guarantee that it'd work. I'm not sure
>>> whether we'd be doing users a favour here.
>> There is a technology to do this but it's not GPL...
>> OpenSolaris and Nexetra use ZFS which supports snapshots. Before each
>> package installation transaction (i.e. one upgrade of N packages) they
>> take a snapshot of a system, do the upgrade. If the user doesn't like
>> it, they can rollback to any of the previous snapshots because they
>> are available.
> Won't that only be an acceptable solution if the user is willing to
> throw away all the work they've done since the package upgrade? ZFS is
> cool and all, but this doesn't seem to address any of the hard parts of
> why downgrades aren't supported now.
Ah, maybe this is the reason you thought of that. The default Ubuntu (or
any other distro) will just make one filesystem and stuff everything there.
That is not the case with OpenSolaris based ZFS root capable
installations. While the whole disk maybe taken up by a zfs pool, the
installation will create three at least zfs filesystems. ROOT/,
ROOT/opt, export, and export/home all exist on my OpenSolaris
installation. So all data is stored in the user's home directory is not
at all affected by upgrades or downgrades.
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