Hacking SD card file system

[jlynton]

Update:
A week has gone by, and I can confirm that the device is snappier, loading books, opening shelves, finding an author &c. all show a considerable improvement over the FAT32 format.

[filmo]

Ext 2 or 3 should be made default for Kobo by having a reader format SD card setting while still allowing FAT32. This way everyone can have benefit of using much better modern file system. Why not? Windows

[Ken Maltby]

Hmm... so your file handling performance, when working on your Linux PC, with your Linux
OS device, is improved when you change the device's storage to a native Linux file system?

OK.

Luck;
Ken

[jgoguen]

Not exactly. Performance improves when switching to a file system that has generally better performance. It just so happens that ext4 was chosen and it just so happens that's a "Linux file system" on a Linux-based device. I suspect that you would also see a (much smaller) performance boost with the exFAT file system if the Kobo shipped with the necessary file system drivers in the kernel. Which it can't cheaply do for exFAT, Microsoft has that locked down with patents. If the device had support for BSD's FFS I would expect even better performance.

The fact that a Linux PC is being used to manage the device is unimportant. You could install ext4 support on your Windows PC or your Mac and see exactly the same performance improvements. Although I think you would have to create the device file system on Linux anyway...

[DNSB]

Originally Posted by jgoguen

Not exactly. Performance improves when switching to a file system that has generally better performance. It just so happens that ext4 was chosen and it just so happens that's a "Linux file system" on a Linux-based device. I suspect that you would also see a (much smaller) performance boost with the exFAT file system if the Kobo shipped with the necessary file system drivers in the kernel. Which it can't cheaply do for exFAT, Microsoft has that locked down with patents. If the device had support for BSD's FFS I would expect even better performance.

The fact that a Linux PC is being used to manage the device is unimportant. You could install ext4 support on your Windows PC or your Mac and see exactly the same performance improvements. Although I think you would have to create the device file system on Linux anyway...

I used MiniTool Partition Wizard to create an ext2 partition on an SD card, mounted it using ext2Fsd so I could use Calibre to copy files to it and the card works in my Aura. I haven't played with it enough to say if there is a speed increase or not.

Regards,
David

[Ken Maltby]

Originally Posted by DNSB

I used MiniTool Partition Wizard to create an ext2 partition on an SD card, mounted it using ext2Fsd so I could use Calibre to copy files to it and the card works in my Aura. I haven't played with it enough to say if there is a speed increase or not.

Regards,
David

I, for one would be very interested in the results. Particularly, as relates to each of
the performance issues that have been exposed here. A large number of files, a large
number of "Shevles", ability to work well with calibre.

Luck;
Ken

[DNSB]

Originally Posted by Ken Maltby

I, for one would be very interested in the results. Particularly, as relates to each of
the performance issues that have been exposed here. A large number of files, a large
number of "Shevles", ability to work well with calibre.

Luck;
Ken

I've gone back to a FAT32 formatted uSD card. As I've posted elsewhere, I've been having fun with the very slow bootup when I insert an uSD card with 1600+ books on it. The time dropped a bit with the ext2 formatted card but it was a pain having to reformat it each time I did a new test cycle -- SD format tool to wipe the card, Partition Wizard to recreate the ext2 partition and then Ext2FSD to mount the volume.

I don't use shelves -- I'm an old fashioned person and search works for me -- and am only using Calibre now due to issues with cover images for files copied to the uSD card.

Regards,
David

[Ken Maltby]

So, interesting but no clear advantage worth the effort.
Thanks much.

Luck;
Ken

[flowoeB]

hi,

if I understood correctly, you all were talking about an external uSD card.
is it possible to format the third partition called "KOBOeReader" on the internal sd card to ext3 ?
(i installed a 32GB uSD inside today - working fine but with FAT32)
maybe it can be done even without taking the SD card out of the reader? (I didn't really like to open it...)

I'd like to access the partition with the paragon driver on my Mac

[Ken Maltby]

Warning opinion/theory, not verified in practice:

If you can see and manipulate the partitions, you should be able to give it a try.

If you can create a clone of the whole card, still inside your Kobo, from your Mac,
then write the clone image to another 32GB card outside your Kobo, then do the
changes on that card, you could then clone that whole card and then write that
image file onto the 32GB card inside your Kobo. Or you could just open the case
again.

Luck;
Ken

[flowoeB]

sounds like opening it again is the easier way

so, I will clone the image i made to another sd card - but instead of expanding the fat32 partition I'll expand and format it to ext3.

what file would I have to change to make the aura mount the internal 3rd partition correctly - and will it be seen by the pc (with installed ext3 drivers) when plugged in via usb?

[tshering]

Originally Posted by flowoeB

sounds like opening it again is the easier way

If you a reluctant to open it again, this post might be interesting.

Originally Posted by flowoeB

what file would I have to change to make the aura mount the internal 3rd partition correctly - and will it be seen by the pc (with installed ext3 drivers) when plugged in via usb?

I think you have to modify these two files:
etc/init.d/rcS
usr/local/Kobo/udev/usb

Originally Posted by flowoeB

and will it be seen by the pc (with installed ext3 drivers) when plugged in via usb?

I am pretty positive about this.

[flowoeB]

thank you, found the initial mount of "onboard" at boot and the rmount after unplugging the usb. I'll simply do a mount without the vfat argument if there is an error on the original mount line... will give it a try tomorrow...

[PeterT]

Just remember that updated f/w from Kobo will replace those modified scripts, so changes will need to be made to them before the upgrades are allowed to happen.... Otherwise the device might be left in a non functional state.

[flowoeB]

thank you for the tip.
just accidently broke the display of my aura - old people with their clumsy hands - didn't even get the chance to open it a second time... bummer... ordered a new one so I'll have to wait until it arrives


this is what I changed for testing:
in usb:

	if [ -e /drivers/$PLATFORM ]; then
		PARTITION=/dev/mmcblk0p3
		MOUNTARGS="noatime,nodiratime"
	fi

	mount -o $MOUNTARGS $PARTITION /mnt/onboard

in rcS:

mount /dev/mmcblk0p3 /mnt/onboard

I removed the dosfsck lines - I don't want to use any fat formated thingy anymore...

also removed the # for the external sd card in usb and sd

I formated the 3rd partition to ext3 on my mac and restored it from a backup

now I'll wait...