Waleed786 - The iPhone uses a more centralized file system than the N900, in that the entire OS runs off the root, no separated partitioning. Where as the N900 uses a classic Linux partition scheme. This reflects the way each company view Linux or Linux like OS use. Apple modified the FreeBSD in some very closed ways and the iPhone reflects this way of altering the OS behavior. Where as Nokia seems to have approached it from the much more purist point of view, thus making the device very familiar to anyone who has mucked around on the console for more than a few minutes.

In doing that Nokia has allowed for a great deal of flexibility. The power user can do many "normal" Linux file related tasks. The root partition isn't meant to be the "working" day to day partition on most Linux systems. The /home and /usr are usually setup in separated partitions. The big "No Memory" issue comes from using up the small root, simply moving various parts of the /var and /usr/share folders clears this up nicely. With far less chance of causing issues like JB'ing an iPhone. Would be nice if an app was made to do exactly this a nice gui for end users to clear there root folder.

Remember the N900 is more akin to a micro-mid and not a phone. Its file system, memory management and capabilities reflect this. The iPhone is a phone and in turn its guts reflect that.