Supercomputing for under £100
I've been following the Adapteva Parallella project since interviewing its creator, company founder Andreas Olafsson, about his Epiphany architecture a few years ago. To encourage adoption, Olafsson launched a Kickstarter project to create a development board: the Parallella. Billed as the first 'supercomputer' for under $100, the $99 board combined a dual-core ARM processor and FPC A with a 16-core Epiphany-III coprocessor and proved a smash hit - so much so that it's only now, around two years later, that I've finally been able to get my hands on a review sample thanks to a partnership with RS Components.
First, the bad news: there's been a bump in price as the design of the Parallella board has shifted. In the UK, it's available from RS in three flavours: the headless Micro-Server at £95.77 inc VAT, the Desktop Computer at £117.67 inc VAT. and the Embedded Platform at £189.53 inc VAT. The extra cost of the latter comes from its use of a Xilinx Zynq 7020, a more powerful system-on-chip (SoC) that includes an FPGA large enough for you to upload your own logic to it - a task that isn't easily achieved on the other models, which reserve the bulk of the FPGA for the logic that ties the Epiphany chip to the system.
It's the Epiphany chip that makes the Parallella stand out. Featuring 16 cores - with a 64-core Epiphany-IV in the works - the chip gives the Parallella considerable parallel processing capabilities above and beyond its rivals in the same form factor and power envelope. In total, you can expect around 20 gigaflops of single-precision compute - enough to do some very clever work in the computer vision, image processing and parallel mathematics fields.
Now, the good news: Adapteva has made sure the Epiphany is accessible to everyone. All models of the Parallella run, by default, an Ubuntu Linux variant from a user-supplied micro-SD card and, with the exception of the cheapest Micro-Server model include a micro-HDMI port for connection to a display. Connecting a keyboard and mouse is a little more awkward, requiring a USB On-The-Go adaptor that won't foul the micro-HDMI port, but once you're up and running, using the Parallella is like using any microcomputer.
Some example programs are included in a publicly accessible GitHub repo, to help programmers get to grips with the Epiphany. Yes, that means little existing software works out of the box with the Epiphany, although work is ongoing to port projects such as the BOINC distributed computing system. It’s enough to get started, though, and a bundled version of the popular password cracker John the Ripper running on the Epiphany-Ill chip, via its semi-compatible OpenCL layer, outperformed the same program running on a single core of my PCs AMD A10-5800K processor, at a fraction of the power draw.
Here we come to one slight negative of the Parallella though: under load, the Zynq chip - not the Epiphany, surprisingly - generates enough heat to bum itself out if it isn't adequately cooled. In a cool environment, the bundled chunky heatsink is enough; for heavy use, though, a fan should be strapped on top of it. My preference for this job is the all-in-one acrylic case and fan combo available from http://groundelectronics.com
While the relatively high price and esoteric nature of the Epiphany core may put off some people, I heartily recommend the Parallella for anyone wanting to do a bit of programming -the availability of ARM, FPGA and Epiphany cores make it a great one-size-fits-all development platform. However, its GPIO headers are broken out as hard-to-find Samtec high-density connectors, making it less tempting for electronics hobbyists.