DLoop comments

[Matt Zimmerman]

On Wed, Sep 28, 2005 at 06:10:27PM -0400, Phillip Susi wrote:
> Matt Zimmerman wrote:
> >No, the .deb actually contains these files.  It has a tarball inside.
> 
> Yes, and the tarball contains the path names of the files.  When 
> extracting the tarball, you could remove the binaries and replace them 
> with a list of the names of the files that were removed.  Given that 
> list finding the installed copies of the files is trivial.

You and I are clearly working from different definitions of "trivial".
There is a lot more to installing a .deb than placing each file at a certain
path.  I don't see much point in arguing this, though; you can trivially
prove me wrong by implementing it and showing us how well it works. :-)

> >They can remove packages later.
> 
> Yes, but it wastes time installing them in the first place.

Copying the installed filesystem is very fast.  Much, much faster than
installing .debs.

> >They can install them later (this is already how the existing installer
> >works).
> 
> Yes, but why install old packages first only to have to turn right 
> around and install their updates?  It's another waste of time.

It actually isn't if, you think about it.  Consider that the current
approach gets the user up and running immediately and lets them use the
system while they wait (potentially hours) for updates to download, rather
than delaying the entire installation while waiting for them.

> >That's OK.
> 
> How so?  The configuration used on the livecd might fail when you try to 
> boot from the hard disk.

No, it won't.  Why do you think it would?

> The configuration of a freshly installed package might need to be modified
> to work on the cd, but when you install to the hard drive, you want the
> freshly installed configuration.

This is never true with an Ubuntu live CD.  It is specifically designed to
work with a standard, pristine filesystem.

> I guess you could make a script to revert such configurations when doing 
> the copy, but it seems like that would be harder to maintain than simply 
> installing the packages like normal, and letting them configure 
> themselves when unpacked, the way the installer does now.

The pristine system is always available on the CD and could be copied
instead.  I'm undecided about copying the configured system vs. copying the
pristine system and then configuring it again, though I'm leaning toward the
former.  There's actually a very minimal amount of livecd-specific
configuration done at runtime, and it would be very simple to roll back.

-- 
 - mdz