Google Android Gingerbread Is Using EXT4

[phoronix]

Phoronix: Google Android Gingerbread Is Using EXT4

Earlier this year Google announced they would be switching to the EXT4 file-system on their Linux servers (previously they were still using the mature EXT2) and at the same time it was made available they had hired Ted Ts'o, the lead developer of this file-system currently in use by a majority of the new Linux desktop distributions. Google's continuing to love the EXT4 file-system and now with their new Android 2.3 "Gingerbread" operating system for smart-phones and other mobile devices, they are switching to EXT4 there too...

http://www.phoronix.com/vr.php?view=ODkwMA

[deanjo]

Unfortunately a new file system won't do much for certian models such as the Samsung Galaxy S. A couple of our sales reps have them and are on their 4th and 5th replacements despite only having them for only 4 months (memory going bad). (It also happens to be the only android offering the local telco offers).

[Shining Arcanine]

Smart phones typically use raw flash devices, which means that the filesystem must implement wear levelling. Ext4 to my knowledge does not implement any wear levelling, so this change will kill smart phones very quickly. It is great for fans of forced obsolescence, but it seems a little evil to me.

[deanjo]

Smart phones typically use raw flash devices, which means that the filesystem must implement wear levelling. Ext4 to my knowledge does not implement any wear levelling, so this change will kill smart phones very quickly. It is great for fans of forced obsolescence, but it seems a little evil to me.

Wear leveling really shouldn't be a concern on a smartphone. The amount of read/writes with a typical user would be at pretty much the lowest end of the scale. The average USB key would go through many more read/write cycles and seem to be more reliable. It's not like your going to use a smart phone for daily backups.

[TechMage89]

You could also implement wear-leveling at the block level, though. Perhaps they do that?

[manninej]

Uh. Something is not quite right here. EXT4 and NAND flash devices just are not compatible. Scary that such a prominent developer as Ted can miss this point.

[_txf_]

I suspect that this will only be applied to devices with an ftl device onboard. I just don't see how you could apply ext4 (which is for block devices) to NAND flash (which is a mtd device).

However recent HTC devices have been using emmc for their storage and ext4 would work there as emmc has the flash controller and nand embedded directly in the same ic.

I do wonder what performance benefits one would get using ext4 besides having extents.

[deanjo]

Uh. Something is not quite right here. EXT4 and NAND flash devices just are not compatible.

Since when?

[dalingrin]

Most new phones are using block level storage these days. Wear leveling is implemented in hardware. For example, the Nexus S uses an internal SD card for storage. Ext4 is perfectly suited for this as many Galaxy S users can attest.

[manninej]

Since when?

I should have clarified that raw NAND devices are not compatible. If the things are as Dalingrin says then it can be used.