I'd never use a journaling FS on a flash FS. Simple as that. Didn't use it on my eeepc and won't use it on the n900.

I tend to use ext2 though I would be interested in ext4 without a journal.

I'm actually surprised that Nokia has chosen ext3 for /home.
has anyone already performed benchmarks with ext2 vs. ext3 on home?

would be UBIFS (as for root) another option or is impossible to access
the internal flash directly as for the root fs?

the flash for root fs is supposedly faster than the 32GB flash.
Is there evidence for that? AFAIK UBIFS uses online compression,
which may cancel out the faster speed?

Ubifs is for non-wear leveled flash storage. From my understanding the MMC is wear leveled.

UBIFS works on top of the UBI subsystem which performs wear-leveling
http://www.linux-mtd.infradead.org/doc/ubifs.html

I wonder whether is possible get raw access to the internal flash (MTD subsystem)
or wether the wear-leveling is implemented in hardware.

Yeah. I'm aware of that. Hmm I doubt we could get raw access. From what I understand the internal memory is eMMC which would I guess be the same as using an MMC/SD card. From my understanding the controler handles this.

BTW, I have added a brainstorm for improved flash partitioning in (hopefully) future releases
https://maemo.org/community/brainsto...internal_flash

Couple of things:

First, let me recuperate for clarification:


From Factory the N900 basically has the following "physical" partitioning sceme:

- 256MB "root" on a seperate (faster) chip as ubifs
- 2GB /home on mmc as ext3
- 27GB /home/MyDocs on mmc as vfat which will be exported to usb on demand
+ in addition about 27 virtual partitions via remount or link or whatever


This partition scheme causes problems because
- many foreign packets install in "root" which runs out of space
- native packages put their data into the /home partition (via remount in /opt/... ), which is small.
- an open opposition towards vfat in general for 42 geekish reasons (as in 'true, but my mom would never notice the difference')

- we cannot just resize "root" (repartition) because it's on a seperate physical device.
- we cannot get rid of the vfat-partition completely because the camera application (anything else?) can only store data on vfat
- some users might need vfat for MS-Windows compatibility


Is this about correct or did I miss something?


Now moving on:

1. When doing the VFAT via the sparse image: does it shrink again once files are removed? Someone mentioned earlier that it wouldn't...

2. If it's just the camera, what about having it store data onto the SD? There's already an option for that builtin. I use the SD for photos anyway, so it wouldn't be much of a loss
Plus a removable card is much easier to repartition when size requirements change than the internal memory. And unlike windows the N900 does detect and automount SD-cards with multiple partitions on them.


Dreaming further: I don't use Windows, so with the camera shooting to SD, to hell with the internal vfat partition. Could I instead just get one large ext3-partition containing /home (and /home/MyDocs as a subfolder if I must) and export that to usb?
ext4 would also be interesting, but I'm not sure wether the N900's kernel supports it

Would such a setup have any other nasty side effects? Say Memory-settings GUI-integration and stuff?

As for installing foreign packages: I don't completely understand yet how this works exactly, but couldn't we just "export" /usr/ to the large flash the same way /opt/ is exported now? Shouldn't that solve the problem and be a lot easier than migrating "root" to a LVM on a live system?


Off topic:

I have found the performance of SDcards to be largely independant of their classification. Using a transcend class6 card now which gives exactly the specified 6MB/s write and slow reads, wheras my old Sandisk Class2 card gives me 16MB/s write and 30MB/s reads. Major break-ins when the card is near full, but it's definitely significantly faster in daily use nontheless.
So no, it's not the N900's cardreader that's slow, it's the cards!



Yeah, those were the days! Big, ugly brick that Universal was. Nice video playback for the time, though. And I do miss the keyboard!

Not exported... unix has this nice ability that you can mount more or less anything anywhere.

So you could have an emmc partition and mount that as /usr

so pardon my ignorance, but then why all the hassle with root on LVM? sounds overkill if a simple remount can get the job done...

don't mean to offend, just want to learn!

It was one of the suggestions. Simple as that.