Maybe the new exFat would be the best fit here? It has specifically been created for these problems. Not sure if they kernel has support for it allready.

I haven't contacted MS, but from my experience with other big companies replying to requests from mere mortal, and considering MS's arrogance, i'm betting my bank account the reply will be something to the tune.
They can barely make their own systems work, they have no reason to implement something that will only benefit the competition (*nix systems are pretty much the only ones using ext_ )
There are 3rd party apps to do the mounting, like these, though i screwed up my ext3 by using this one

If anyone wants a desktop OS that supports modern open filesystems, doesn't try to lock their data into secret proprietary formats, and is written by people that will listen to their users, they can, of course, just get one.

OK. By anyone, I suppose that I mean any large corporation. M$ claim that they are listening and responding to customer clamors for interoperability, which they seem to define as providing peeks at their sooper sekrit interface specifications. Oh, and agreement not to sue (for a limited time) for merely implementing an interface. They seem to be either blind or clueless that interoperability is a 2-way street.

I have opted out of dealing with them (or Apple) and have been doing heavy voting with my wallet. But, after all these years, I still have to deal with limitations in usability and convenience in even the most open devices/platforms that jump through hoops while bending over backwards to pander to people that demand (without even having to voice it) to be able to plug in all sorts of secret, proprietary crap and have it just work.

Even all the above would be a bit more bearable if it weren't hard coded and tedious to work around.

Well, reverse engineering is a lot of work, MS didn't bother for quite a long time to update FAT32 (it almost died), but now, since it became the de-facto standard for SD, why shouldn't they throw in a new, updated and "free" FS to support it?

Mac OS X does at least support reading ext2/ext3 file systems out of the box.

I ain't no Kernel hacker or Linux expert, but I think it should be possible to compile fuse+ntfs-3g to work on Maemo. It probably would be a lot slower and power hungry than FAT. Anybody willing to give it a shot?

Since he is talking about big files, ntfs-3g will be a problem... Performace degrades drastically over 4GB even on my 4X core desktop, especially writes. So probably a waste of time.

can you explain this a bit further please

how can i format an sd card to ext2 on a windows machine and what lis 'scp'?

scp is secure copy, it is used with ssh (secure shell). Once you climb a bit of a learning curve and maybe go through a bit of configuation pain, they make using a bunch of computers from each other much easier.

Formatting an SD card as ext2 from a windoze computer is probably easy enough with www.cygwin.com installed. Asking on a cygwin mail list or searching google is probably the best way to find out how.

You have just goaded me into trying it on my n900 since I want to save wear and tear on the n900 back cover and its SD socket. This is the first time I've used sfdisk, which seems easy to make a mistake on. I use linux fdisk all the time, and am much more comfortable with it, but it is not on the n900.

I used ssh to log in to the n900. The thought of using the n900 keyboard and display for this was just too painful.

First I copied the card to my laptop, the DCIM directory that the n900 hijacked without permission for n900 pictures and videos, and my podcasts directory. After I mounted the SD card with an ext2 partition, the n900 picture application no longer saves pictures there. I consider that a feature.

I doubt that the n900 will automatically mount an SD card with an ext2 partition. I guess I will find out the next time I boot.

Following is a list of the sequence of the commands used. gainroot is required. All other commands are standard on the n900. I will follow with a description of the steps. Make sure no applications are using the SD card before starting. All commands have been copied and pasted from the ssh session used to format my SD card to ext2 in my n900.

Slight changes of some of these commands can trash the OS or your data on the n900. It would be safer to use some other computer with an SD card reader. Windoze users might consider booting from a knoppix CD. Device names would be different.

root ( become root), then unmount the SD card,
list its partition table, print the type of the first partition, change the tpye to 83 (linux))
format the ext2 partition and mount it.
Everything after the mount makes my particular directories and changes the owner from root to user.

It took 32 minutes 48 seconds to copy the data off the SD card over wifi and 58 minutes 12 seconds to copy it back. On the 8GB card with FAT32, the data took 3.1GB. On ext2, it took 2.5GB. So ability to store large files and need 20% less space to store the files.