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.
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
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.
New Raspberry Pi development vm version 0.2
[update: There is a tiny little buglet in the vm that slipped passed me as it didn't crop up when I was testing that yum worked as I didn't install a library that needed to go in the top level of the rootfs. If you get a lot of errors about unpacking or mkdir... when trying to install something using yum then you'll need to do the following
cd $HOME/raspberry_pi_development/f13arm_rootfs
sudo chmod -R 777 *
and that should fix it. sorry about that.
the torrent is now available.]
I have put together a new VM for developing software for the Raspberry Pi. I've made a few tweaks and cleaned up a lot of stuff and it's a much more pleasant setup and easier to use and update without making a whole new VM. I also used fedora13 for ARM as the seed rootfs so it should be possible to just swap files from/to a real Raspberry Pi and it should just run and you can update the seed rootfs as well (hopefully I guessed Raspberry Pi standardized educational disto correctly). I was planning to use fedora16 as the guest OS in the VM but after struggling with some of it's foibles for several hours and having to rebuild it a few times i gave up and reverted back to a ubuntu based release. it's currently compressing and uploading and with my upstream speed being so rubbish it'll take about 8 to 18 hours to finish but once it is finished i'll post a link to it and hopefully someone will make a torrent of it.
http://russelldavis.org/RaspberryPi/raspberrypi_dev_vm_02.torrent
Below is the README that is included with the exported appliance.
-------
RaspberryPi Development Virtual Machine 0.2
This is an exported virtualbox virtual machine for developing software for
the RaspberryPi. It is setup using the git versions of scratcbox2 & qemu (19/01/12), the fedora 13 for ARM as rootfs seed & arm-2011.03 codesourcery toolchain.
The root password is toor and the username and password for the normal user
is raspberry/password
To compile software for the raspberrypi as you would normally on an x86 machine
prefixing sb2 to any command. e.g. instead of gcc hello.c -o hello you would type sb2 gcc hello.c -o hello
To update, install or remove libraries and software in the seed rootfs use the command sb2 -eR yum ... where update, install, remove etc.
If you want to build and install libraries to use when building other software
that are not availble via fedora yum then rather than prefixing with sb2 prefix the command with sb2 -eR e.g. sb2 -eR make && make install
You can upgrade scratchbox2, qemu, the rootfs or toolchain quite easily as they are all in seperate dirs inside the raspberry_pi_development directory. it shoudl be possible to just swap them out when/if you need/want.
I have installed apache2 adn linked the $HOME/build directory so you can download anything you build to another system. You will probably want to change the network settings for the VM from NAT to Bridged though.
An ssh server is also installed so you can ssh in to the vm if you want as well (same proviso as above though. You'll need to change from NAT to Bridged to get it working).
If you have any other questions about the VM then you can send them via my blog (http://russelldavis.org) or post on the raspberry pi forum. (http://raspberrypi.org)
I have added one of my favourite bash aliases to the .bashrc doch is very handy in case you forget to use the sudo prefix to a command. just type doch and it'll redo the command but with sudo added.
Russell Davis (ukscone) 20/01/12