How to break the Internet in 10 easy steps
This morning (February 29th 2012) at some ungodly hour (1am EST/6am UTC) the Raspberry Pi was finally released. Originally the Raspberry Pi Foundation was going to manufacturing the Raspberry Pi themselves and sell it in their own online store but instead they have setup a licensing deal with 2 companies (Premier Farnell/RS Components) who will make the Raspberry Pi themselves, using their manufacturing facilities and sell them in their online stores. There have been some initial teething problems with this but on the whole this is a good thing as it will mean more people will be able to get their hands on the Raspberry Pi much sooner than if the Foundation was handling the manufacture of the Raspberry Pi themselves. The foundation now gets to concentrate on other things such as writing documentation and actually teaching programming to children rather than spending enormous amounts of time on behind the scene things not directly related to their ultimate aims.
Tips for preparing an SD card for the raspberry pi on windows
The Raspberry Pi will probably be available to buy in the store sometime within the next ten days and one of the operating system sd card images is already available (debian) with another to follow in a day or so (fedora) so it's time to start thinking about making an sd card for use with the raspberry pi.
If your main machine is a linux system then you should have no problem, a standard dd will be fine but under windows not only do we not have a dd program (we do but it's not a pleasant experience and windows users are not command line junkies on the whole so use something like Win32DiskImager or equivalent) but there are a couple of gotchas that might catch the unaware out.
The main gotcha is that although your computer has a builtin sd card reader/writer and it works with your cellphone or camera sd card perfectly well it might not work for creating a bootable sd. The biggest problem builtin sd card reader/writer is the ricoh one in HP laptops although other makes of sd card hardware and laptops also have this problem. When you use a builtin reader/writer and it is goingto fail it doesn't always tell you that it's failed so the first thing you now something is wrong is that your raspberry pi (or other target device) won't boot So although you have a builtin sd card reader/writer it is a good idea to get hold of a USB SD card reader/writer and use that for making your bootable SD card. [I have no real idea why builtin reader/writers have problems making bootable sd cards but my thinking is that the controller in the builtin ones was cut down for windows machines to save a few pennies as noone thought that they'd want to write to the 0 to xxxx areas of the SD card]
The other gotcha you should be aware of is that SD cards are formatted and written to in a slightly "weird" way. An unformatted/blank SD card is actually full of 1's and when you write to it it just flips the appropriate bits to 0. An sd card can read at the bit level but only writes at a block level so you'll end up with areas that can't be used for writing any more as they need to reverse a bit back from a 1 to a 0 to perform the write and deleting/erasing the file won't actually free up all that space as it spans several blocks. So if you are going to use an SD card that you have used before you'll want to format it before using it with the raspberry pi. Don't use the windows formatter with your SD card as although it'll sort of work it won't have set all the bits to 1 instead user the panasonic sd card formatter which you can find at http://panasonic.jp/support/global/cs/sd/download/index.html [I can never remember which way around it is for when an sd card is in an unused state, whether it's all 0's or all 1's but i'm leaning towards all 1's as that is what has seemed to have stuck in my head].
To quickly summarize if making a bootable sd card on windows.
- Use a USB SD Card reader/writer
- Use the panasonic sd card formatter
- There is a windows version of dd but use Win32DiskImager or equivalent instead
Building an Algol68 interpreter for the Raspberry Pi or How to be a world champion procrastinator
I'm got disgusted with Virtualbox when trying to get a USB webcam working with it so rather than building a new linux system to use for developing some object indentification from a webcam software i decided to see if there were any nice open source compilers or interpreters for things like Algol, Snobol4 etc.
I found an Algol68 interpreter on sourceforge that seems to be still maintained (last update in 2011 and a related piece of software updated this year) http://algol68.sourceforge.net/ so i thought i'd give it a go using an ARM fedora rootfs. I ran the configure script and saw that it would like gsl & ncurses so I added the runtimes and headers using yum inside scratchbox2 and then reran the configure script and then make and after adding the usual "-fsigned-char" it built with non of the usual X86 C to ARM C warnings.