PyCon: Eben Upton on the Raspberry Pi

Raspberry Pi Foundation executive director Eben Upton started his PyCon 2013 talk with a complaint that he had just been upstaged. He normally asks the audience "who has a Raspberry Pi?", but conference organizer Jesse Noller had "ruined that" by announcing that all attendees would be getting one of the tiny ARM-based computers. The Python Software Foundation, which puts on PyCon, had arranged for Raspberry Pi computers to be handed out to all 2500+ attendees. It also set aside lab space on the second floor of the Santa Clara (California) Convention Center where attendees could "play" with their new computers—complete with keyboards, monitors, breadboards, LEDs, and other peripherals.

Genesis

The Raspberry Pi, which is a "small computer for children", came about due to observations that Upton and his colleagues made about the computer skills of high school students applying to study computer science at the University of Cambridge. In his time, anyone that had an interest in computers could probably get their hands on one that would beep when it was turned on and boot directly into a programming language (typically BASIC). Everyone knew how to write the canonical program:

    10 PRINT "MYNAME IS GREAT!!!!"
    20 GOTO 10

The availability of those kinds of machines allowed potential students to have a basic level of programming knowledge. But, when interviewing applicants in 2005, they noticed that many lacked that "built-in hacker knowledge". In addition, the 80-90 available spots were only being contested by around 200-250 applicants, rather than the 500 or so in the 1980s and 1990s.

The problem, it seems, is that the 8-bit machines that were readily available in his time no longer exist. Game consoles now serve a similar niche, but are not programmable and are in fact programmer-hostile because of the business models of the console makers. In addition, those 8-bit hacker computers have been "eaten from the top" by the PC. The PC is, obviously, programmable, but users have to choose to install programming tools. This "tiny little energy barrier" is enough to reduce the number of applicants with the requisite skills, he said.

So, there is a niche available to be filled. In order for a device to do so, it has to be interesting to children, Upton said, which means that it needs to be able to play games and have audio/video capabilities. It also needs to be robust, so that it could be "shoved" into a school bag many times without breaking. It needs to be cheap, "like a textbook", which only "shows that we didn't know what textbooks cost".

The target price was $25, so the team spent a lot of time trying to figure out what can be fit into a device with that price. They started with an Arduino-like microcontroller system, but that "didn't meet the 'interesting to children' test". After university, Upton went to work for Broadcom, where he is still employed, though he mostly does Raspberry Pi work these days.

Working at Broadcom led him to a chip with a proprietary RISC core, which the team was able to get to boot to Python. It would also do 720p video and could hit the $25 price point. At that point, they decided to set up a foundation. The "Pi" in Raspberry Pi is Python misspelled, Upton said, which was done because he thought the symbol for pi (π) would make a "fantastic logo". But it turns out that the pi symbol has never been used by the foundation and he regularly has to explain that he does know how "Python" is spelled.

Switching to Linux

As the project progressed, he realized that the team would have to write all its own drivers for devices like network interfaces or SD card readers, which was time consuming. About that time, Broadcom released another version of the chip with an ARM 11 core. "There are advantages to being on the chip design team", Upton said with a chuckle, suggesting that the ARM was added for "unspecified business reasons". The ARM core meant that the Raspberry Pi could benefit from the "enormous investment" that the community has made in Linux.

The BBC Micro was one of the original 8-bit computers that shaped many enthusiasts' early computer experience, so the foundation wanted its computer to be called the "BBC Nano". It approached the British Broadcasting Corporation (BBC) about using that name several times, but were always turned down for "complicated legal reasons", Upton said.

As part of the effort to convince the BBC, though, a 45-second video pitch was created. Once that video got to YouTube, it had 600,000 views in a single day, a day which Upton spent "not working for Broadcom" and instead "pressing F5" (to refresh the page). That night, he sat down with his wife and realized that they had "promised 600,000 people" that "we would build them a $25 computer", but had "no idea how to do it".

The CPU fit within the $25 budget, but there are lots of other components that go into a computer board. Those can cost a few cents or even more, which all adds up. It took a while, but the team finally fit the design into the budget, or nearly. The Model A is $25, but the more-popular Model B, which has ethernet, more memory, and an additional USB connector, came in at $35.

Upton had just gotten an MBA degree, so he "knew all about business models", he said with a laugh. The foundation had raised $250,000, which could be used to build 10,000 of the devices, so the plan was to build those, sell them, and take that money to build another 10,000. But they started seeing danger signs almost immediately, he said. When a "buggy beta version" of the SD card image that could only run in QEMU was released, it was downloaded 50,000 times. That many people downloading software for hardware that didn't exist and might not for quite some time led to the realization that the "interest was high". Given that the lead time for more systems was three months or so, and there was now a worry the devices would sell out in a week, something needed to change.

Luckily, he said, they started working with two UK companies that put up the capital to build all of the Raspberry Pi computers that were needed. The foundation licenses the name and "intellectual property" (IP) to those companies who "do the heavy lifting". In the end, there were 100,000 orders on the first day, and the millionth Raspberry Pi was sold "sometime last month".

It has been a truly amazing year, Upton said. One of the interesting transitions that he has noted is that the content on the web site has shifted away from mostly being about what the team (and "other adults") were doing to get the devices out the door. Over the last six months or so, the site has covered what "children are doing with the Pi".

Examples

Saying that he wanted to "inflict" some pictures of those activities on the audience, Upton shifted gears to show and describe what has come about since the release of the Pi. As a "graphics hacker", he expected that much of the interesting work would be graphics-related, but that turned out not to be true. There are few graphics demos, though he encourages people to write more.

The first stop on the quick tour was a "Moog-like" synthesizer program that is available for free. The second stop involved beer. It turns out that there is an "enormous overlap" between people who like programming and people who like beer, he said to big audience cheers, which led to a number of different projects. The computers are being used to run both home and commercial brewing equipment using BrewPi, for example.

There is a project to assist with focus stacking using the Pi, which can replace $1000 worth of photography gear for getting better focused images when doing macro (extreme close-up) photography. There is also a huge retro-gaming community for the Pi. The hardware is powerful enough to emulate not only the consoles that he played with, but can also emulate the following generation of gaming consoles that he "complained about" because they "destroyed the era of computers that I grew up with", he said with a grin. Art installations are another fairly common use for the Pi, and Upton showed some lighted paper boats at Canary Wharf on the Thames river.

"Dr. Who and space and the Raspberry Pi all in one" is Upton's description of his favorite hack. A weather balloon with a Tardis as its payload has been used to take pictures from 40km up. That means that a "space program is within the budgetary reach of every primary school in the world".

The Raspberry Pi community has been very inventive with extras. Upton noted The MagPi magazine, which has type-in listings of programs, hearkening back to the 1980s. Typing a program in has its advantages, including "learning opportunities" from mistyping. There is also a Haynes manual for the device.

The simplest cases for the device are PDF files that you print on the "thickest paper you can get through the printer" and fold up into a case. While the Pi is described as "credit card sized", it is actually about 1mil off in both dimensions, he said, but in a "fluke", both the X and Y dimensions turn out to be a multiple of the Lego basis unit size. That led an 11-year-old girl to create a Lego case design for which she now gets royalties. Since she is 11 years old, she takes her royalties in Lego, so she "now has more Lego than me", Upton said.

There is evidence coming in that kids are using the Pi to learn to program, he said. He showed one who is learning with MIT Scratch and noted that the foundation is spending some money right now to get better performance for that language on the Pi. Though he set out to try to help solve a problem for Cambridge University, it "turns out that kids all over the world want to learn to program". He showed a photo of some kids from Uttar Pradesh in India using the Raspberry Pi. Those kinds of pictures give him some hope that they are actually accomplishing something with "this tiny computer".

He noted that there "needs to be a hook" to get the Pi into a kid's life and "apparently a lot of children like to play Minecraft". Mojang, the company behind Minecraft, has done a port of the pocket edition to the Pi: Minecraft Pi Edition. That version has a socket that can be used to talk to the game world from any programming language, which "gives kids a reason to program".

Upton put up a "Try to take over the world" map showing where the computers have been shipped to. Taking over the world seems to be progressing well based on that map. North America has become the continent with the largest "run rate" (i.e. purchase rate) in the last three months, he said, and became the largest install base as of last month. They would like to sell "a hell of a lot more" in South America and India, he said, but "we'll get there".

Another interesting geographical note was a change in the manufacturing location. In the beginning, the boards were built in China, unsurprisingly. Sony contacted the foundation and said that it could build the boards at its factory in South Wales for the same price point. Since September, Raspberry Pi boards have been built there, which is a "big deal" for Upton as he comes from about 10 miles from the factory. The fact that the "lowest-priced general-purpose computer" can be built at a factory in the developed world is "good news" for anyone concerned that there would be no manufacturing in regions like Wales.

Python

There are several connections between Raspberry Pi and Python, starting with the name. The chip was designed using Python, Upton said. He was on the GPU team for the Pi's Broadcom 2835 chip, which used Python to "design the whole damn thing". All of the multimedia IP was verified using Python because it is "100 times quicker" to do it that way. Python and its tools are much easier to use (and faster) than Verilog tools.

The Raspberry Pi benefits from the large body of existing Python (and other interpreted languages) code. Python brings a whole set of applications and tools to the ARM Linux environment. Finally, Python also provides one of the teaching languages for the device. The device supports Logo and Scratch for the youngest children, and will always support C and C++ for people who "want to get close to the metal", but Python has a special place as a learning language. Upton said that Python allows educators to tell children "learn this language" and "you will be on a smooth curve" leading to a language that lots of companies program in. There are no discontinuities in that curve, he said, which is important because it is those steps where students get lost along the way.

Wrapping up, Upton had three more topics on his mind. At some point "soon", the Pi team will need to decide between Python 2.7 and 3.3. It is already a bit confusing as some packages (e.g. PyGame) are only available for one of the two. He is also looking forward to PyPy as a way to get better performance out of the fairly modest Pi processor. Beyond that, the "boot to Python" idea is still floating around, though it is not yet clear what the best teaching environment for the Pi will be. In closing, he hoped that all of the new users in the room would visit raspberrypi.org and report back on what they did with Raspberry Pi.

Many of the examples Upton gave are not particularly Raspberry-Pi-specific, in that they could run on any Linux system. But the Pi provides a convenient package, with compact size, low weight, and lots of connectivity options, that makes it a nice target. While the GPU drivers leave a lot to be desired and the USB driver is a mess, it is still a rather interesting device—particularly at its price point. Could something better have been made? Perhaps, but it would take a dedicated group of folks to get together to do so. Upton and the Raspberry Pi Foundation have made their mark, some friendly competition would make things even more interesting.