Thread: [Under consideration] More efficient and flexible use of internal flash
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titan is offline titan
2009-12-28 , 23:31
Posts: 946 | Thanked: 1,650 times | Joined on Oct 2009 @ Germany
#4
Hi Luis,

Originally Posted by soeiro View Post
1) Do you think we could have some sort of script to backup and restore the whole setup before and after applying a firmware update? (I know that until Nokia actually changes N900 default filesystem layout we will have to use some sort of workaround)
IIRC a firmware reflash did only overwrite the separate root flash memory but did not change the MMC flash at all. So there is no need to perform a backup only for the reflash (you should always do backups, nonetheless). If you want to backup the paritition table you could simply use sfdisk or save the first sector of the flash.
2) What would be the best file system for a flash-based disk? I'm a little bit worried about XYZ wearing the disk too much because of too much updates to some sectors. Anyway, FAT32 updates the FAT too much, anyway.
apparently UBIFS (the fs for the root fs) is not possible.
Nokia decided that ext3 with writeback cache is a good idea for /home and I guess it was a informed choice?
3) I also agree with your last points about having a more standard Linux directory structure. It would make it a lot easier to use a tool like rsycn or Unison to synchronized your desktop files with the N900.
that's actually a good point! you could use your N900 as a backup device for your desktop home and vice versa.
4) Do you think we could also throw into this mix some sort of selective Cryptography (for example: keep a subfolder encripted)?
everything which is possible on Linux should be possible on the N900 as well.
for instance, you could have a encrypted loop device using a file on the ext3 partition
and bind the directories into your home.
5) Finally. I'm assuming you have already managed to get your idea working on your device. What are your thoughts about it? Anything unusual happened?
no problems so far. My next plan is to run some benchmarks on the root, the ext3, the vfat partition and vfat image to check how much overhead the loop device causes.

I wish Nokia would get rid of the MyDocs partition so that applications don't have to deal with a non-POSIX fs but can use a large POSIX fs.