ubuntu-phone team mailing list archive

[Oliver Grawert <ogra@xxxxxxxxxx>]

Am Donnerstag, den 20.08.2015, 07:47 -0400 schrieb Eric Holmi:
> Ok. I like your profile image. Once in read/write, everything is the
> same as the desktop, right? What are the most prominent differences?
> 
no, it isnt comparable to a desktop install, the writable setup is still
in place on top of the now-not-readonly-mounted readonly rootfs ... apt
will evcentually break completely and you will have to re-flash...

writability is achieved by creating bind mounts into a rw partition ...
dpkg uses hardlinks when updating files in packages ... hardlinks do not
work across partition boundaries so you will end up with broken apt/dpkg
as soon as such packages show up.

the OTA upgrade on the other had is applying a diff that has been
created between two rootfs tarballs, this can only work properly if your
device has the exact same base tarball as the server that created this
diff did use for the creation. if you make the readonly side writable
and change it, this isnt the case anymore.

while you can use apt very carefully to install a single package (as
long as it doesnt touch existing files), you can not do upgrades via apt
and you also risk upgradeability through OTA if you changed any contents
of the writable partition.

essentially apt support is there for developers to test their changes
before landing them in an image and then re-flash their device after
doing this test. using apt permanently isnt supported and has never been
the focus.

ciao
	oli