[sf-lug] The desktop installer discs are not APT repositories ... upgrade Ubuntu 12.04.x --> 14.04.x

[Michael Paoli]

> From: "Daniel Gimpelevich" <daniel at gimpelevich.san-francisco.ca.us>
> Subject: Re: [sf-lug] upgrade Ubuntu 12.04.x --> 14.04.x
> Date: Mon, 27 Jul 2015 21:51:02 -0700

> On Mon, 2015-07-27 at 20:38 -0700, Michael Paoli wrote:
>> With DVD/ISO can probably, like Debian, use apt-cdrom, so it will know
>> about the available ISO image, and not download from Internet what it
>> can retrieve from optical drive.  But should still get additional
>> updates
>> (e.g. security updates, critical bug fixes) from The Internet, to
>> cover
>> what's not yet made it to released DVD ISO.
>
> That is how upgrading using an alternate installer disc worked under the
> hood. The desktop installer discs are not APT repositories and cannot be
> used this way.

Ah yes, good point.  Forgot about that little, uhm, detail <cough, cough>.
Yes, rather annoying that.  Same kind of issue with the Debian Live DVDs.
Also can't even make updated versions of 'em with jigdo - have to use
something more like zsync.

Well, when all else fails, read the documentation.  ;-)
http://www.ubuntu.com/download/desktop/upgrade
...
https://wiki.ubuntu.com/TrustyTahr/ReleaseNotes#Upgrading_from_Ubuntu_12.04_LTS_or_Ubuntu_13.10
Gee, they make it seem/sound so simple and if there's hardly anything to
consider ... uhm, ... "of course" they've got a commercial
interest/bias in making it seem so.  ;-)

Let's see ... Debian on the other hand :-) ...
7.x --> 8.x ...
$ (for url in \
> https://www.debian.org/releases/jessie/amd64/release-notes/ \
> https://www.debian.org/releases/jessie/amd64/release-notes/ch-about.en.html \
> https://www.debian.org/releases/jessie/amd64/release-notes/ch-whats-new.en.html  
> \
> https://www.debian.org/releases/jessie/amd64/release-notes/ch-installing.en.html  
> \
> https://www.debian.org/releases/jessie/amd64/release-notes/ch-upgrading.en.html  
> \
> https://www.debian.org/releases/jessie/amd64/release-notes/ch-information.en.html  
> \
> https://www.debian.org/releases/jessie/amd64/release-notes/ch-moreinfo.en.html  
> \
> https://www.debian.org/releases/jessie/amd64/release-notes/ap-old-stuff.en.html  
> \
> https://www.debian.org/releases/jessie/amd64/release-notes/apb.en.html \
> https://www.debian.org/releases/jessie/amd64/release-notes/relnotes-index.en.html  
> \
> https://www.debian.org/releases/jessie/amd64/release-notes/relnotes-glossary.en.html
> do lynx -dump "$url" |
> sed -e '/^References$/,$d'
> done) |
wc
    3007   17706  127798
$
... so, around 3,007 lines, 17,706 "words" of documentation/instructions
on the release notes around such ... so ... one is *much* less likely to
encounter any surprises ... especially of the unpleasant variety.
On the other hand, Ubuntu is more like, "you should probably backup.
Upgrade is easy (so claimed/implied), and, oh, if you encounter any
bugs, here's the URL to report 'em".  ;-)