usb disk, in reverse?

Chris Murphy lists at
Mon Dec 9 03:58:14 UTC 2013

On Dec 8, 2013, at 8:20 PM, Fernando Cassia <fcassia at> wrote:

> On Sun, Dec 8, 2013 at 11:26 PM, Chris Murphy <lists at> wrote:
>> , when NTFS is a viable cross platform option.
> You want journaling on "dumb" flash media without TRIM support, really?
> Think about it…

The FTL is the opposite of dumb, therein lies a good part of the problem with SC and USB flash media. Since the journal is constantly writing over the same LBAs, the FTL knows underlying pages can be marked for discard. TRIM isn't necessary because a fs is journaled. The FTL will map the LBA's as the journal writes to already erased pages, marking the former pages for discard. It doesn't need TRIM to do that.

In any case, for flash media there isn't much benefit for the journal, because flash is either fast enough to not benefit from obviating fsck, or the media is small also obviating speed benefit over fsck. But NTFS is more resilient than exFAT, and it supports large files and volume sizes.

> FAT32 is the only filesystem that can currently be read by the vast
> majority of devices (cameras, music players, smartphones, TVs,
> Smart-TVs, TV Media Players, set top boxes…)

Yes, I agree it's remarkably unfortunate that we users lack sufficient choice in this area. Samsung thankfully agrees and has open sourced f2fs. Hopefully the work for a Windows and OS X driver moves along quickly, and any needed commercial license incentivizes a long overdue purging of FAT32 and stops exFAT adoption. 

Chris Murphy

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