[maemo-developers] [maemo-developers] Re: [maemo-announce] New Nokia 770 software image available

[From: Antonio Orlando]

> dpkg packages has postinst and prerm scripts that get executed while  
> installing/removing package. It it hard to guess what they do (and  
> modify) so you may not know what exactly to backup and may loose some  
> effects of those scripts when restoring just the files from packages.
> [...]
> tarring whole disk will work. Backing up only rendom selected part not.

That's good. Anyway it seems I have not been able to explain exactly what  
I'm asking, I'll try to be more clear: is it possible to backup *almost  
all* the directories and files via ssh and tar, flash the device,  
reinstall the ssh server and restore the backup'd stuff into the renewed  
device, in order to have everything working again, good as before or  
better, with minimum effort? (except some eventual bugs introduced with  
the new firmware, of course)

With "almost all", really I mean *everything*, just excluding the  
dirs/files that we should not backup because they're unnecessary (I don't  
know: proc, lost+found, mnt, ...), and the dirs/files that we should not  
backup because we want to keep the new ones (that is, the updated files  
after the flash: we have to avoid backup and restore of the old ones,  
otherwise we've lost our time ;)

 From what has been said here on the list, I've seen why the approach of  
rough overwrite via ssh cannot be chosen to directly update the files that  
would be flashed with the flasher tool, but still it's not clear to me the  
reason why we should not backup and restore "all the other stuff" using  
this straight way. I'm asking again because I prefer not to upgrade the  
firmware if this means I have to re-do all the steps that make my 770 work  
like it is now. It's not too much stuff (yes, a fraction, compared to what  
some of you there have on your 770), but time is precious and I hope  
(vain?) there is some better solution for upgrading without pain: the  
release of a new firmware for a device usually is a full  
happyness-trigger, but if I think to what this currently implies it risks  
to become a no-no-please! ^__^;;

If still I'm not clear, here it is my question re-explained in a more  
developer-friendly way (I hope line-breaks will not make this unreadable):

////////////////////////////////////
// This is the "normal" approach: //
////////////////////////////////////

stuff = [collection of files and dirs that I can find via ssh]

770_before_flash = [%stuff% in my 770 before flash]

770_after_flash = [%stuff% in my 770 after flash]

hard_work = [on %770_after_flash%: reinstallation of all the packages, set  
up of all the settings, configuration of all the configs, direct copy of  
all the non-packaged apps, creation of all the symlinks, etc. (put here  
whatever has been written on 770 internal memory after last reflash)]

770_after_hard_work = [%stuff% in %770_after_flash% after %hard_work%]

if (%770_after_hard_work% WORKS_LIKE_OR_BETTER_THAN %770_before_flash%)  
TIRED_BUT_HAPPY
else DOH


////////////////////////////////////////////////////////////
// This is my question: will the following approach work? //
////////////////////////////////////////////////////////////

stuff = [collection of files and dirs that I can find via ssh]

flash_stuff = [collection of files and dirs that flash would touch]

ghost_stuff = [collection of files and dirs that we need not to backup  
because they are just there as linux works (proc, lost+found, ...)]

good_stuff = [collection of files and dirs that make my 770 unique, my  
favourite apps, settings, etc.]

if (%flash_stuff% + %ghost_stuff% + %good_stuff% != %stuff%)  
PLEASE_SUGGEST_WHATEVER_ELSE

770_before_flash = [%stuff% in my 770 before flash]

770_after_flash = [%stuff% in my 770 after flash]

not_so_hard_work = [on %770_after_flash%: install xterm and openssh, copy  
and overwrite the previously backup'd %good_stuff% of %770_before_flash%]

770_after_not_so_hard_work = [%stuff% in %770_after_flash% after  
%not_so_hard_work%]

if %770_after_not_so_hard_work% WORKS_LIKE_OR_BETTER_THAN  
%770_before_flash% then NOT_SO_TIRED_AND_HAPPY
else DOH

///////////////////////////////////////////////


I hope that's clear enough now. Let me know if not, I'll try something  
else.

-- 
Antonio