Raspberry Pi: Personal Perspectives
I have been playing around with the Raspberry Pi (Pi) for two months now. I started by installing Raspbian on a spare 4 GB memory card. I also had a wireless Wifi dongle and a wireless keyboard-mouse lying around. I plugged the WiFi dongle and the dongle for the wireless keyboard-mouse in the two USB ports of the Pi and when I plugged in my spare mobile charger into the Pi’s power input, the Pi booted. I felt lucky to see the display on the TV without any hassles. So far all in all, out of the box experience and all I had bought was the Pi. I already had the other stuff lying around. It was fun to see something on TV that I am used to seeing on a computer monitor.. The next thing I did was fire up the Python interpreter and tweeting the output of os.uname( ).
Next things I tried to do was like what I had seen most people do was trying to make a media centre out of the Pi. And few other things like setting up a audio server, etc came to my mind. But then, I thought to myself – I don’t have a huge media collection, nor do I play games, nor do I sit back a lot and watch stuff. I think I am better off doing something else with the Pi. Its Linux in a more constrained environment after all. I fiddled around a bit with the Pi after that. Then, finally couple of weeks back, I installed the Fedora 17 ARM remix on the Pi. That was the point where I really started using the Pi.
Fedora 17 on the Pi
One of the first things I liked about the Fedora remix was that the SSH server was installed and enabled out of the box. Once I was done with firstboot, I plugged the TV jack out and work on the Pi by SSH-ing into it (The Pi is connected to my home network via the Ethernet port).
I have been documenting my experiments with Fedora on the Pi here . As you can see, most of the programming languages, frameworks and tools there is all the typical things you would be using on any Linux system – BASH, Python, Ruby, Flask – you name it. It was like – so it worked on Linux on the big machine, let’s say if its there on Pi and everything was pretty much so close to same that it started to seem like a chore – more about documenting what I was doing in the hope that it might be useful to some one and may be I can use them as a base for a book/article in the future. There in lies the essence of the awesome work done by the Fedora ARM team which made things a chore. Thank You folks! And of course to all the Python programmers who have made their packages available via PyPi. pip-python was indispensable.
No more a chore
Things changed a bit yesterday. I fiddled around with the GPIO pins for the first time. Using the WiringPi’s gpio command, it was as easy as it gets. I then used the Python package RPi to interact with the Pi pins from Python and it was quite dandy. As you can see from the documentation , among the two packages one of them was already installed and the other was installed from PyPi. Finally, that was something I can’t do so easily on my big Linux machines. That also meant, I do not have to use Arduino to fiddle around with some basic, hobbyist electronic stuff. In one of the coming days, I might hook up the Arduino with the Pi.
Role of Abstraction Layers
The most basic operating system course introduces it as an interface between the user and the hardware – an abstraction separating software from the hardware. I think the Pi is a great example for educators to show exactly what they mean. Have a traditional computer and a Pi side by side – write the same program and run it both the devices show them. That should be quite intuitive. The fact that I started finding things a chore was because the operating system was abstracting out the hardware from me.
Experimenting with C
The good thing (and the bad thing) about Python and Ruby (for example) is that you are one layer higher (than C) in the abstraction hierarchy. C is one layer close to the bare metal and hence should be an educational exercise to play with it on the Pi and compare it with an an Intel or AMD computer. That should help illustrating the differences you need to ponder about when you are programming in C (or C++) and intend your program to be also working on other architectures.
I touched on this in this article titled “Compilation and Interpretation in C and CPython“.
The experiments will continue.