Thursday, 24 May 2012

Life with Pi

    My Raspberry Pi single board computer arrived just over a week ago after a long wait for my ordered unit to be manufactured and shipped. I wrote back in early March about my thoughts on the product launch and I outlined my plans for the device a couple of weeks ago, now I've had it in my possession for a week here are my thoughts about the board itself.
    On first unboxing the unit my reaction echoed those of other reviewers, this is a small device. Of course we all knew it would be credit card sized, but having the board in front of you really brings that home. We've become so conditioned to computers requiring significant space for peripherals and heat management that one without that need is something of a shock.
    Gathering together the required peripherals was an easy task. I already had network and audio cables, as well as a micro-USB phone charger and my venerable Logitech wireless keyboard and mouse combo. I had to buy an HDMI to DVI cable because my TV is in reality an Acer monitor hooked up to a PVR and doesn't have HDMI. Thankfully the days of crazy pricing for DVI or HDMI cables are behind us.
    Similarly, downloading the Debian Squeeze reference distribution from the Raspberry Pi website and installing it on an SD card was very straightforward. Some SD cards have been reported as having problems with the Pi, I can confirm that my Lexar 8Gb SDHC card has no such issues.
    So with all peripherals and software in place and connected, I turned on the telly and plugged in the phone charger. Without fuss, the LEDs on the Pi lit up, and the Linux boot screen appeared on the TV. Success!
    Success, that is, until it hung during the boot process. But a very helpful message explained that this can happen at first boot and simply rebooting the device would fix matters. A further reboot and login process, and I had a bash prompt. My £25 Linux PC was a reality.
    Given a working computer with a Linux command line, the world is your oyster. I am reviewing the hardware for this piece rather than the software because I feel every Pi owner will have their own plans for the device and simply describing a Linux distribution will be of little interest. So the software is only described in this piece in scant detail, and to give an idea of the speed of a Raspberry Pi compared to a more familiar computer.
    So I typed startx at my prompt, and was rewarded with the LXDE desktop. As a simple first task, I loaded the BBC Weather site and then GMail in the bundled Midori browser. Hardly heavy stuff, but it gives a good idea of the speed involved.
    I have heard the Pi described as having performance similar to a Pentium II with a very fast graphics adaptor. By coincidence one of my desktop PCs is a Pentium II 266 running Lubuntu, so given that the Pi's Debian does not yet have driver support for the graphical acceleration I would say that the performance of both machines is very similar indeed. Browsing is a usable experience, but a slow one. A typical web page will take over ten seconds to render, but in-page Javascript features are usable in real time once the page has loaded. Services like GMail for instance are a bit slow-feeling, but not so slow as to be impossible to use. Having used the Pentium II as my main development platform for several years before moving to my laptop I do not expect a Pi with similar performance to struggle with the kind of scripts I am likely to use it for. On that note, I installed the Python Natural Language Toolkit package which will be a significant plank of the project I plan on using my device for.
    If I have any software gripes, they are minor and will I am sure be fixed in future distributions. The image is for a 2Gb SD card, and though instructions are readily available online for extending the partition onto a larger card they are not for the faint hearted and would benefit from being made easier as part of the Pi distribution. GPartEd is bundled and might perform this task but trying to use it revealed a further gripe; the administrator password doesn't seem to be available. Of course I could use sudo from the command line to achieve this aim by other means, but to someone with little knowledge of Linux this would be a show-stopper.
    I would like my Pi to run full-time next to my router, processing keyword data. To this end my interest in the Pi centres on its low power consumption and heat dissipation, I do not want a traditional PC with all its heat issues running full-time in my home. I put the Pi to the test on this front by constantly reloading the BBC website for several minutes in Midori, causing the CPU graph to show as maxed-out. If the Pi had a traditional Intel processor then merely running LXDE would cause it to be too hot to touch, as it was I could put my finger on the Pi's memory/processor combo and feel that it was merely discernibly a bit warmer than its surroundings.
    The Pi's small size means that there is plenty of space behind my telly for it next to the router. But with a bulky HDMI cable plugged into it there was something of a feeling of the tail wagging the dog as the weight of the cable threatened to pull the board with it. Also the board layout with cables on all sides meant that positioning it was slightly difficult. But that is an acceptable compromise as has been explained by the Raspberry Pi team, for reasons of size and cost. My solution to the mechanical issues of a small board held only by a selection of cables was to make a simple case from a surplus business card box, a speedy procedure involving a set of nail scissors. This case does not seem to result in the Pi becoming too warm, and will probably end up being fixed to the router using sticky Velcro pads.
    In conclusion, after a chance to play with my Pi I am still extremely impressed by it. Sure, the software distribution has a few very minor gripes, but this is very much still a product in development by a volunteer organisation. Some care is needed in mounting or enclosing a Pi to protect it from damage, but that is no more than would be expected for any printed circuit board. Otherwise it is an extremely powerful computer for its exceptionally low price and with a low power consumption, so I look forward to it spawning the same diversity of creative computing that its 8-bit forebears did. If you haven't ordered one, do so now!


  1. Interesting, thanks -- do you mind if I share this on?

  2. Great review John and very useful for when I have the time to power up my new shiny RPi