I know that maemo's root memory is limited to 256 MB. What can I do if I want to install apps by make (compiling, installing) in standard way without risking using out rootfs? Is there any working solution for n900 PR 1.3? I don't want to install (only backup) anything on my 4GB memory card

Install to /opt partition and, if needed create symlinks in rootfs. The /opt partition is 2GB big and you can put all binaries and libraries there in a folder like /opt/mysuperapp and then create symlinks of .so libs to /usr/lib and of you application binary executable file to /usr/bin (if you want to run it from terminal without prefix, i mean "mysuperapp" instead of "/opt/mysuperapp/mysuperapp"). There is also kumatux environment ( http://kumatux.org/Install.html ) in which you can install some programs to your EMMC or memory card, but I don't recommend it unless you are only compiling and installing command line software for your own use (I don't recommend deploying your apps in such environment to wider audience).

another option for developing-on-device, look at at this thread: http://talk.maemo.org/showthread.php...ghlight=don900, all is explained and a nice tool is being delivered to help people setting up everything.

Don't most packages have a configuration option in their config script that tells it what directory to install to? Like, when I was compiling GIMP (don't get excited at the sound of that - it runs but clicking into it breaks touch input inside other programs and itself, so that's at a standstill until I get around to working on it more) for the N900 you could tell it what filepath prefix to use with a config parameter before compiling. For every package that does, you can just manually add that flag when running config, and then make and make install from there.

There are some possibilities to even enlarge the 2GB optfs partition described in this fine wiki entry: http://wiki.maemo.org/Repartitioning_the_flash

The problem is that what the OP was talking about won't be helped by increasing /opt / /home space. For example, on my N900, I have about 9 GM of space partitioned as opt. (I used the eMMC image modifying route. But for all that space, it doesn't change the fact that the rootfs is still under one GB, and thus everything has to be manually moved to /opt.

My other idea is doing it the way Qole's Easy Debian is made. Create virtual partion file, place it in EMMC or SD and use easy-chroot scripts to mount it in filesystem and use just like any other directory in your system. You could also build a custom filesystem with custom apps there (someone today announced here that he will maybe create specialized and customized Easy-Debian based image files for web developers - with LAMP, etc. - and for other use-cases if there is interest), I don't have the link now, but you can find it easily I guess. I have set up maemo sdk this way on my device (this is probably similar to DON900, haven't chacked) using custom ext2 image file and modified easy debian scripts, it's actually quite easy to do Qole has also some more images ready for chroot: http://qole.org/files/

Oh I entirely agree with you on both the previous post and this one, don't get me wrong - both are good at what they do - the former gives much more actually "useful" space on-device, the latter gives you a chroot sdk environment.

It's just that each of those doesn't directly help the OP's question: how to get optified packages by default when running something like "make install". (Although I think you could put a chroot inside /opt/something and then permanently add that chroot's (s)bin directories to your path, then make install from within the chroot. Since the binaries inside the chroot will still be N900's-Maemo5-runnable, assuming you set up the chroot correctly. Although I'm not sure if I understand chroots right, but I think it should be possible to have a chroot that's just part of the filesystem it's in, rather than a seperate file...? [so all the stuff inside it is visible/runnable even when the chroot isn't running])

That was exactly my idea You don't need chroot into the image file, you may mount it in the same way EMMC and SD cards are mounted on system (just 1 command in xterm or in some script if someone wants it automated) and the file is mounted and can be accesed under some path of filesystem. For example one may want to mount file /home/user/MyDocs/nicebigimage.ext3 under /opt/awesomefs and then just update patch so binaries are search in /opt/awesomefs/bin and libraries in /opt/awesomefs/lib (just example paths). Honestly, if I were to package some bigger software for N900 (bigger=above 1GB), I would even create a package that way. That just makes it impossible to connect N900 to computer as external usb drive while running programs from this mounted image. If someone would have enough patience and would really need it, he could write even some scripts and connect them to dbus signals and unmount or mount this virtual fs accordingly.

It's late in here (and end of week), so I hope I wrote my thoughts in understandable way.