NFC unsuited to "duplicating" your tablet [LWN.net]

NFC unsuited to "duplicating" your tablet

Posted Nov 20, 2012 23:51 UTC (Tue) by tialaramex (subscriber, #21167)
Parent article: Android 4.2, tablets, and related thoughts

A naive "duplicate" feature would operate by copying the entirety of tablet A onto tablet B. Certainly the worst case is /very close/ to this even if we're quite clever about it and copy only the user's data and preferences.

The largest Nexus devices are currently 32GB I believe. On a GigE link, with a fast enough TCP/IP implementation (neither of which is available on any tablet today) that's maybe six minutes of data under ideal circumstances.

At a (slightly) more realistic 50Mbit high speed local WiFi it will take more than two hours. At that point you're definitely asking the user to plug everything into the mains, and find something else to do while they wait.

But our esteemed editor suggests NFC. I suspect he has not tried doing very much with NFC, because the target usable bandwidth is less than a megabit. Copying one tablet's contents onto another can be expected to take as much as a fortnight, and of course any real user would long before that grow tired of the "Please wait..." message and give up.

to post comments

NFC unsuited to "duplicating" your tablet

Posted Nov 21, 2012 0:08 UTC (Wed) by corbet (editor, #1) [Link] (1 responses)

Wifi is clearly better for the data transfer, but NFC is a good device discovery and "user is present and wants this" verification mechanism.

NFC unsuited to "duplicating" your tablet

Posted Nov 21, 2012 1:49 UTC (Wed) by ewan (guest, #5533) [Link]

AIUI the way the 'Android beam' feature works is to use the NFC to negotiate a device-to-device Bluetooth connection which then does the actual data transfer. The NFC step is essentially for authentication - on the basis that it's just so short range that you must have deliberately brought the devices close together to do the transfer.

NFC unsuited to "duplicating" your tablet

Posted Nov 21, 2012 12:02 UTC (Wed) by paulj (subscriber, #341) [Link] (2 responses)

The 'adb' tool already provides image backup/restore functionality. You need to unlock your Nexus first of course.

NFC unsuited to "duplicating" your tablet

Posted Nov 21, 2012 14:25 UTC (Wed) by smurf (subscriber, #17840) [Link] (1 responses)

Image backup+restore probably won't work when the new tablet isn't exactly the same model as the old one. Besides, this idea should work without the help of a 3rd device.
IMHO using NFC (or display+scan a QR code) to setup a data channel should be rather trivial. Then blast the actual data across with WiFi. The heavy lifting (i.e. extract and restore state) can be done with Titanium Backup which you should use anyway.

Any takers?

NFC unsuited to "duplicating" your tablet

Posted Nov 21, 2012 17:24 UTC (Wed) by paulj (subscriber, #341) [Link]

True, though you can backup your apps separately from the system at least. So it at least a partial solution.