Stats in bed, part 2: Linux on Android

Never let it be said that Robert forgets to come back and finish off a job, although it might take a really long time. Last time (goodness, nearly 3 years ago; the antiquity of part one is shown by the long-dead term “phablet”), I was poking at Ubuntu Touch to see if it might offer a way of doing analysis on the go. Soon after that, I looked into more lightweight Linux implementations.

Firstly, your device will need to be rooted (no giggling at the back), as shown by the open padlock when it starts up. I discussed this last time; there’s plenty of advice online but basically it helps a lot to have a Linux computer (in this as in so many other ways).

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Everything that follows happened a couple years ago so use your brains in checking details of apps etc if you want to try it out. I accept no responsibility for anything, ever.

So, the general idea here is to have a Linux virtual machine on your Android device. I started off using an app called GNUroot which was easy to use but had a limitation in getting files off the virtual space into the real world. When I restarted it, it made a new virtual drive, wiping out old files. Ok except for the fairly common crashes which lost all the work done in that session. It couldn’t work directly on the Android part of the machine (so to speak).

The next attempt was more stable but a little more complex. I installed Linux Deploy, which creates a 4GB virtual drive image and keeps that between uses (no more lost files). Instead of having one app that acts as a VM, I SSH’d into it using the app JuiceSSH (there are several like it).

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The first step is to open Linux Deploy and press Start. An IP address appears at the top and we will use this to communicate with the VM using SSH.

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Then, I went to JuiceSSH and chose (or typed in) the IP. Boom! You’re in Linux!

 

Awesome. Installing and updating programs sender to be a bit hit and miss, sometimes throwing up odd messages. So, to use R on the terminal, I relied on having the latest unstable build from Linux Deploy. 

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I could even write files out.

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In Linux Deploy, you can have the Android memory appear like a mounted drive to the Linux VM at ../../mnt/0

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Coming out of Linux, we find our new file is right there, like magic.

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I still find it pleasing to look at the file in a text editor in Android and marvel at how it got there. Simple pleasures.

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So that’s fun. But a little clunky. No compiling C++, no Stan, or those other new-ish R packages that rely on Rcpp to build faster machine-code bits and bobs, though you can use lots and lots of R stuff. The antiquity of these experiments means I didn’t try Python out but I’m sure it would work just fine. Also, as self-styled clinical research maverick @anupampom pointed out to me, a major advantage is that you can take that linux.img file, stick it on another device with Linux Deploy, and carry on where you left off. Nice. It’s like a Docker container (kind of).

For reasons that may start to come into focus now, I gave up on doing phablet data science about this time. Not that way anyway. But the question of remote, platform-independent analysis and programming remains. And in part three, I’m going to close down this discussion with the real solution to this, which is in platform-independent interpreted languages.

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