This is the title of an article in the Sept 12 edition of International Science Grid This Week. It is described a paper by Busching, Schildt and Wolf, presented at a workshop held as part of the 32nd International Conference on Distributed Computing Systems in Macau, China.
They reported on a simple proof-of-concept experiment: they connected six low-end Android phones to create a mini-cluster or mini-grid. Now, it wasn’t a very powerful grid: each phone ran 5.8 megaflops, and the cluster ran at 26.2 megaflops when connected by Wi-Fi. But the authors pointed out that smartphones can run much faster, up to 100 megaflops currently, and huge numbers of smartphones (which now outsell PC’s) can be connected by WiFi. Moreover, the project showed that connecting the phones together does not require complicated software or set up, and the phone itself functioned normally when part of the grid. In fact, a more serious problem than set up would be to convince people that it is safe to allow their phones to be used in this way.
In the experiment, the authors performed only minimal modification of the Android OS. To quote: “…root access to the smartphones was obtained by running the z4root tool. Then we created a Debian ARM installation in a folder on a SD Card using debootstrap. The rooted phone allows to get shell access and then chroot into the base Debian system installed by debootstrap. Please note, that by using this method we do not interfere with any software already installed on the phone.”
They installed an MPI library, and obtained reasonable scalability (see figure below) when running the LINPACK benchmark, which solves a dense set of linear equations.
So what about applications? They cited the example of benefits to volunteer computing, which could benefit from the immense number of devices involved. They cited SETI@home as an example. Are there other examples people can think up?