Additional Raspberry Pi VM Information
I was informed yesterday that there seems to be a problem following my VM setup instructions when using Ubuntu 11.10. I spent about 5 hours and 3 Ubuntu 11.10 installs checking this and it certainly seems to be the case that without an awful lot of fiddiling and complications that are just not worth the bother. So for the time being the recommended guest os's for building your own VM are Ubuntu 10.04LTS, Fedora16 or Debian (I haven't built the VM on Debian for a long time so i'm not sure exactly which version to recommend but I can't imagine that Debian will be much of a problem with any recent versions. If anyone has a problem with Debian please let me know.)
Once again if you are using my instructions to build the Raspberry Pi development VM (or a VM for any development using Scratchbox2 and/or qemu) i'd recommend (in no particular order) currently using
- Ubuntu 10.04LTS
- Fedora
- Debian
Now a tip when porting x86 code to ARM using gcc. If you get a lot of warnings when trying to build software originally written in C for x86 for ARM especially things like "comparison is always true/false due to limited range of data type" the chances are that you aree being bitten by the fact that x86 compilers usually default to signed chars if not specified by the variable declaration while ARM compilers usually default to unsigned chars. If you are using gcc (which you are if you are using my VM or your own installation of Scratchbox2 then the fix is to use the
-fsigned-char
gcc option. e.g.
gcc hello.c -o hello -fsigned-char
Another thing that might prove useful when you have access to the real Raspberry Pi hardware and the standardized distro is that by default the codesourcery toolchain included in the VM by default builds for generic ARMv5. On the whole this really shouldn't matter as ARMv6 can run ARMv5 instructions but there maybe times when you are doing something that needs to use an ARMv6 specific instruction or you are including assembler in the C code or something else where a generic ARM version binary just won't cut it. In that case using the gcc option
-mcpu=arm1176jzf-s
which specifies that gcc emits the correct instructions for the specific ARM core that the Raspberry Pi uses might be helpful.
e.g.
gcc -mcpu=arm1176jzf-s hello.c -o hello
Hunter Davis has open sourced QuickGrapher
Hunter Davis, no relation (AFAWK) has made QuickGrapher, an HTML5 Equation Solver & Grapher Open Source. He's placed the source on github and in less than a week someone has ported it to Android. I messed around with the beta about a year ago and was really impressed.
Hunter has also Open Sourced another of his projects as well. Source Tree Visualizer which basically turns your source code tree into a real tree in a pretty landscape 
You can find Hunter's post about QuickGrapher here
and his post on SOurce Tree Visualizer here
Even if these two things don't appeal to you Hunter's blog is always a pretty good read.
Setting up a VM for Raspberry Pi development using Virtualbox, Scratchbox2 & qemu (Part 3)
I don't claim that the following is the best way to install scratchbox2, qemu and a seed rootfs and configure them to produce binaries that will run on the real Raspberry Pi hardware. I don't even claim it is the correct way but it works for me and I can almost do it in my sleep by now. The way I do things will probably seem a bit inefficient and in some cases just plain wrong but it's how I work and hopefully they are easy to follow and adapt to your style of working. I also make no guarantees that it will actually work for you at all. Hopefully it will but if it doesn't sorry but oh well. I made the decision when I first started building the development vm that I would place all the required software under the users home directory rather than installing it globally as
- Installing in subdirectories in the user's home directory makes it easy to keep things organised.
- It makes things almost idiotproof when you want to upgrade the ARM toolchain, scratchbox2, qemu or change the seed rootfs etc. as it's pretty much just rename the old directory, create a new directory and if neccessary rerun sb2-init.
Setting up a VM for Raspberry Pi development using Virtualbox, Scratchbox2 & qemu (Part 2)
If you decided to use a Debian or Ubuntu based distro then when you booted the Raspberry Pi Development VM that you just created you will have probably noticed an error message flash on the screen saying
piix4_smbus 0000.00.07.0: SMBus base address uninitialized - upgrade bios or use force_addr=0xaddr
and you'll want to fix that before doing anything else. The Fedora16 VM doesn't produce this error so Fedora users can skip straight to the guest addition installation instructions. I wrote a short post about this error last year but to save you having to go there to read that post the fix [Credit for that fix goes to http://finster.co.uk & Karl Foley] is:
- Start a terminal
- sudo vi /etc/modprobe.d/blacklist.conf
- Add the line blacklist i2c_piix4 to the end of the file and save
- sudo update-initramfs -u -k all
- sudo reboot
Setting up a VM for Raspberry Pi development using Virtualbox, Scratchbox2 & qemu (Part 1)
Last week I released version 0.2 of the Raspberry Pi development VM and I thought that I could safely call it a day because in a few weeks the Raspberry Pi hardware will be available and therefore we will no longer need the VM for software development. So yesterday I announced on this blog and the Raspberry Pi forums that I had decided to EOL the VM and would no longer be updating it as I didn't see the need and i'm not going to have the time to maintain it for the next few months as it takes about 12 to 14 hours to create, configure and upload, 8 to 10 hours of that is uploading using all my upstream bandwidth which is no longer feasible for me to do again until after June.
However, almost immediately after posting that I started to receive tweets and PM's asking me not to stop working on the VM or to at least write detailed instructions on how to create your own VM for Raspberry Pi (or other ARM based devices) from scratch. Yesterday I also finally managed to get SDL programs working correctly, not that I had actually tried that hard previously as the majority of software I was personally interested in building and porting to the Raspberry Pi are text based and at most use ncurses. So although I really won't have time to work on upgrading, tweaking and maintaining the VM personally I have decided that it should continue to live in the form of detailed instructions on how to create your own Raspberry Pi development VM, which is almost mostly transferable to other ARM based devices as well, it's actually pretty much transferable to any device that qemu will emulate but that is beyond the scope of this how-to.
Fate of the Raspberry Pi Development VM
[update: looks like i EOL'ed the VM a day or so too soon seeing as I now have SDL working correctly (mostly) in it now. I'll either do one more release or roll a script and detailed instructions on how to install and configure scratchbox2, qemu and a rootfs (and sbrsh/sbrshd for using the real raspberry pi hardware with scratchbox2) before I do actually EOL it. It might take me a day or so to get to it though.]
In a few weeks we'll have our sticky paws on the real Raspberry Pi hardware which on the whole will obsolete the current VM. I could build sbrsh/sbrshd (mount nfs on the real hardware and use that for cpu transparancy, currently using qemu) which might be useful and there are a couple of tiny buglets and uglyness that I could fix but as it takes about 4 hours to create and clone the vm and configure everything and about 8 to 10 hours to upload somewhere using ALL my upstream bandwidth is it worth it?
I don't mind continuing with the VM if anyone else really wants/needs it but if it's only me that is using it then i'll probably not bother as the VM is good enough for a few more weeks until i/we have the real hardware and i'm kind of running short of tuits for anything that isn't related to a couple of projects i'm currently working on at the moment that will enable me to afford the odd raspi, one, three, fifteen...., but I don't want to leave anyone in the lurch if they really use the VM and would prefer not to have to set it up themselves or don't know how to do it.
So can i have a show of hands in the comments of who would like me to do another release of the VM and/or add sbrsh/sbrshd.
The Raspberry Pi (part three)
[Disclaimer: All opinions in this post are mine and mine alone. Although I am a moderator on the forums on http://raspberrypi.org I don't speak for the foundation and any factual errors, upset I may cause or spelling mistakes are completely my responsibility]
I took a bit of a break from writing this series of posts while I did some work on the development vm which I could do lying down using my eCafe Slim ARM based netbook (ta muchly Obarthelemy) as i'm still in a bit of pain from various aches and pains that being an old fogie seem to bring so sitting down typing for long periods is a right PITB. Now get off my lawn you darn kids. I also wanted to spend some time doing some research for a non-Raspberry Pi related project (although I might try to bring the Raspberry Pi into it if I can at some stage if I can).
So where were we upto at the end of part two? Ah yes The logo competition and MakerFaire NY 2011. i did mention MakerFaire and post a video of Eben's presentation a MakerFaire but I'll expand on that a bit for this post.
Building newLISP for the Raspberry Pi using the development VM
I just put together another quick screencast of the development vm in action. A tiny bit more complicated than tiny basic for curses this time as i had to install a library and edit the makefile a tad and i also ran the test suite inside sb2 as well.
ok enough messing around with the vm for the time being. it's time to start writing the raspberry pi (part three) blog post.
Video of the Development VM in action
I just did a quick screen capture video of the Raspberry Pi development VM in action and have uploaded it to youtube. I'm not very good with making screencasts so please forgive how rubbish it looks.
Dropbox+Bittorrent trick
I don't particularly like cloud type things, it's my data and i want it completely under my control and I don't particularly like dropbox as I don't think I actually trust them. However, I do have a dropbox account because they were offering extra storage from the default for doing a quiz and we all know I like quizzes. When I finished building the new VM I suddenly remembered that my upstream bandwdth is kind of yukky even on my remote server, which had problems with hits last week anyway and although it seems to be coping now after a couple of tweeks, a few hundred attempts to download the VM might make it melt or at least go on strike for better working conditions so I decided that i'd actually use my dropbox account and publish the public url. i was about 25% of the way through uploading it and I suddenly had a horrible thought dropbox probably has a GB/Day limit and that publishing the public url might not be a good idea. So what to do? I could just give the public link to a couple of people and hope that it doesn't escape or I could see if it was possible to use dropbox as a seedbox for a public file.
After a bit of googling I found the following webpage describing exactly how to do it using uTorrent.
https://sites.google.com/site/torrenttricks/use-dropbox-as-a-free-webseed-for-your-torrents
It's actually pretty good however I think it works better with smaller than 2GB files as i still got an automated suspension email about 10 minutes ago but it looks like it was up long enough for a few people to be able to start seeding it. Once my account suspension is over i'll take a look at the process and limits more closely.