Thanks Rob1n.

A few more questions:

1.
Is there any remote possibility that there are packages installed on my n900 by app manager or nokia that can be safely removed without jeopardizing system? If so how can I find them?

2.
Is there a list of groups of apps that will fulfill most of task needed by certain activities that will minimize consumption of rootfs?
Let me explain what I'm leading to:
I want to install latest port of Qt and try it out with some applications that are available in Qt flavor but in GTK+ ports yet (high pathetically). If I install current build it will bring my rootfs to the max. As I already know - this not good. So to resolve this and get what I want I need to find out what I can remove from my system in order to get Qt goodies and still be able to perform tasks I need to do on daily basis.

So it would be good to have some wiki page that will describe to curious noobs like me (who would like to try more before getting attached to something):

1) rootfs limitations (warn us on the possibility to basically render your device unusable by installing too many apps)

2) a brief explanations on GTK+ vs Qt (and consequences to use either one on ones device)

3) list GTK+ based apps (including the one native to maemo 5 image that is factory installed) AND their Qt based counterparts

4) specify instructions of needs to be done to replace GTK+ based apps with Qt based (and vice versa)

This will be helpful even in case that there were no issues with rootfs space limitations.

You can uninstall any packages you like which are shown in the Uninstall view in App manager (other than the Maemo OS update). Removing anything else is not advised, and can cause issues.

The latest Qt (4.6) is optified, so will take up no rootfs space (Qt 4.5 isn't, and takes up quite a chunk). The Qt 4.6 packages are named libqt4-maemo5-...

The other thing to do is make sure that you have the pymaemo-optify package installed.

As for the rest of your points - none of those are things that noobs should be wanting to do. If you don't know the difference between GTK+ and Qt (they're just two interface toolkits), why would you be interested in replacing one (the maemo 5 standard) with the other?

hi all i didnt do a full restore my contacts and messages and settings were all i restored and started again with apps my device is running fine i have no idea what caused the problem as i have almost everthing back on here now from before and all working fine and still have a good vhunk of rootfs free cheers for the help guys