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Messing with DropBox¶
454 words on Software
DropBox is one of the more amazing software tools of the past years. It synchronises a folder from your hard drive to the web, giving you access to its contents from your web browser as well as letting you synchronise it to several machines. Bonus features include the ability to share files and folders with other DropBox users, creating public web links to your files or an automatic photo web site for your Pictures folder.
An amazing number of my friends have DropBox accounts already [if you don’t, consider using this referral link, so both you and me get some bonus extra storage] and rightly so, because it ‘just works’ for many things. The service is reasonably reliable, its speed is all right, its available not just on the Mac but also on Windows and Linux and it’s essentially effortless. Many others tried and failed at achieving the same.
Yes, there are shortcomings of DropBox such as a potential lack of privacy and its disrespect for metadata like extended attributes (to be solved with their currently-in-development 0.8 release, it seems), so you may have to be a little careful, but in general it just works.
An interesting question we asked ourselves is how DropBox handles file system peculiarities. The HFS+ file system in its usual incarnation is case insensitive and case preserving, normalising its file names to a decomposed forms [thus, somewhat confusingly, if you name a file with a composed name, e.g. ‘ü’ (U+FC) in the Finder and copy its name afterwards or have its name in a folder listing by the web server, you get a decomposed result ‘ü’ (U+75 U+308)], whereas the file systems on Linux (Ext-something?) seem to be case sensitive and normalisation agnostic. How will DropBox reconcile these worlds?
Like this, it seems:
Here we see DropBox syncing the file with the composed umlaut and refusing to sync the one with the decomposed umlaut. It appears that they are working in normalisation form C. DropBox does sync both the lowercase and the uppercase umlaut. Of course I won’t be able to get both of those file on my HFS+ volume and a ‘case conflict’ is created by DropBox. In addition to that it seemed that trying to edit the case conflicted files leads to things becoming a bit messy. E.g. after editing on the Linux side which could in principle handle the case difference, I ended up with four files for some reason, all of which had lowercase names:
It doesn’t look like you may lose data because of this, but it does look like things may become a bit messy. Luckily one doesn’t work with files whose names differ just in capitalisation outside geeky tests like this.
