RaspberryPi is a tiny little (credit-card size) ARM/Linux box which has caught the software/hardware/linux communities by storm. Here’s an image from raspberrypi.org that explains exactly what this tiny little machine does:-
Raspberry Jam is a rapidly growing global network of user groups that meet every month to support hobbyists, developers, teachers, students, children and families – in fact, anybody that would like to put their Raspberry Pi to good use.
I have been wanting to mess with this cute little machine with my daughter since I heard about it back in December 2011. With its simplicity, barebones approach and low low cost of USD25.00, it was the perfect vehicle, in my opinion, for introducing her to the notion of computing.
Getting my linux OS into the RaspberryPi was a simple matter of running `sudo python raspiwrite.py` and selecting the appropriate linux distro (specific flavor of a linux operating system) and the script walks you gently through it. Fortunately for me, Debian distro and Arch Linux (arm) distro are both my favorite linux distros; and getting Debian up-and-running (from my Mac OSX machine) was particularly a brain-dead affair. Get started by downloading the raspiwrite.py script from http://exaviorn.com/raspiwrite/. Alternatively, if you are a pro hacker with git chops, get the latest and greatest version of raspiwrite.py from https://github.com/exaviorn/RasPiWrite.
RasPiWrite: your Debian distro set-up via a simple Python script
Once you have gotten your script, insert your blank SD card into your SD card reader connected to your machine, launch your terminal, cd into the RasPiWrite directory to run `sudo python raspiwrite.py` and you should be guided by this well thought out python script and, for now, we will choose the simpler Debian option:
Once done, all we have to do is to plug our Debian-powered SD card into the RaspberryPi’s SD card slot, plug in a 5V power cable into the micro USD, connect a mouse, a keyboard into the USD ports, hook up a HDMI display device (which in my case, is a small, portable projector with a HDMI port) and we will have our little machine booted up. Our installed Debian image comes with LXDE desktop environment, so it was a simple matter of booting up our machine, logging in with the image’s prescribed/default user name and password and launching LXDE via `startx`.
Here’s the debian LXDE desktop in all its glory:
Arch Linux ARM for the advanced Linux users… or Beginners who are brave enough to venture! :-)
Since Arch Linux is my favorite linux distro, it was simply impossible for me not to go down this road; especially since RasPiWrite has gotten it nailed as one of the easy-to-install option.
Bewarned that this Arch Linux ARM install for RaspberryPi does not come with a desktop manager. This means that when you are done, all you really have would be the command line :-)
If this sounds really fun for you, read on!
Following the exact steps above with RasPiWrite, the first problem you will encounter, after the command-line step-by-step guide, will be:-
:: Starting Secure Shell Daemon [BUSY] Could not load host key: /etc/ssh/ssh_host_rsa_key Could not load host key: /etc/ssh/ssh_host_dsa_key Could not load host key: /etc/ssh/ssh_host_ecdsa_key Disabling protocol version 2. Could not load host key sshd: no hostkeys available -- exiting. [FAIL]
Well, this shouldn’t scare us off because
- You are a smart, clever boy/girl, ya? (encouragement for the Kids!!! think of the children!!!!!!!) :-)
- Arch Linux’s wiki is famously detailed and the Arch Linux forum users are crazily helpful
Well, for the uninitiated (windows users and mac users not acquainted with telling your computer what to do with typed instructions in command line), the error message is referring to a process which all linux operating system uses. This little background software is called “ssh” (Secured Shell, like what the first line of the error message says) and it runs as a Daemon (background process, behind the scene when your operating system starts up) to allow a user to securely “login” to a machine. In this case, our RaspberryPi’s Arch Linux ARM operating system (which we have just installed) is having trouble loading up this sshd (Secure Shell Daemon).
Now that we have beginner readers up-to-speed, let’s head over for some help on Arch Linux’s wiki/forum - https://bbs.archlinux.org/viewtopic.php?id=144449
And so it appears that this Arch Linux ARM Operating System image that we have installed does not have a functioning ssh program. The prescribed solution is simply to connect our raspberrypi to an internet connection via its ethernet port and then run:
pacman -Syy pacman -Rsn openssh && rm -vfr /etc/ssh && pacman -S openssh && /etc/rc.d/sshd start
The first command `pacman -Syy` tells our arch linux arm operating system to synchronize the latest open source software with the freely available open source repositories on the internet.
What the long, second line does is to remove any trace of the current openssh program (software “package” is the commonly used term), including other software libraries (dependencies) that it uses, remove all its associated files in /etc/ssh directory, install it all over again and then start up the daemon (the software “process” in the background).
`pacman` is the software “package manager” used by Arch Linux operating system (o yeah, I love operating systems with a sense of humor! And for the arch veterans, you and I know there’s a little easter egg here ya? shhhhhh…). This command sounds scarily convoluted, but all it does is pretty much what you would do on a computer running windows or Mac OSX when you “click on a link” on a webpage to download some software that you want to use, and run the installer which comes with a graphical user interface. In this case, we are simply giving instructions to remove the outdated copy of the “ssh” (openssh) software, and reinstall it with a fresh copy and then start it up immediately.
Once done, we can reboot and you will find that we no longer have that scary error message.
At this point, however, we are still messing around at command line! This is perfect for advanced users who are familiar with administering remote servers and is used to dealing with “headless” (no Graphical User Interface) operating systems and simply wants a clean, barebones installation with bare minimum software so that we can be very very specific about exactly what other type of software we want to install/run from pacman (remember, Arch Linux’s open source software package manager). For a small little machine like RaspberryPi, I imagine this would be exactly what most advanced users expect to use it for.
For those who would still like to have a GUI, we can of course use Debian (or Fedora), or we can still set up a Desktop environment (with wonderful Graphical User Interface that we are used to on Macs and Windows PCs).
Here’s a good resource for you to consider if you want to be part of the geek elite with Arch Linux :-D and still want to have your GUI desktop – http://www.raspberrypi.org/phpBB3/viewtopic.php?f=5&t=6000&p=79061&hilit=Arch#p79061
The Limitless Possibilities of RaspberryPi
This USD25 piece of wonder, like Arduino before it came about, has changed the landscape for small devices. In recent days, a whole range of similar devices from Korea, China (There’s one called “Gooseberry”!) and many other countries will revolutionize what people can create with software and hardware.
Unlike Arduino (microcontroller-based), RaspberryPi is microprocessor based with a full fledge operating system running on it. Already creative and talented software/hardware hackers are making waves with RaspberryPi-based creations like a remote-controlled car -
And a Coffee-making machine! Like this – http://moccapi.blogspot.sg/.
Plans for RaspberryPi!
Meanwhile, Kait-Lyn and I will hatch up our next *devilish* :-D project with RaspberryPi as well… and I have created a new community site called http://LittleHackers.com and Facebook group at http://www.facebook.com/groups/littlehackers with the mission of fostering parent-and-child bonding through creative and fun techie projects!
This is a community that will go beyond RaspberryPi. A really good example of fun projects could be an Aquaponics project! Such as the one that Stephan February has been hacking on at his home for the past 1 year! Aquaponics – http://en.wikipedia.org/wiki/Aquaponics.
At the end of the day, it is all about inculcating a can-do spirit, a “Maker’s Ethos” and a culture where curiosity and application of knowledge really matters. (Yes! More than certs! :-))