The operating system that helps to power a Raspberry Pi – but what exactly is a Raspbian and what makes it Linux?
Raspbian! I use it, you guys use it, I don’t think there’s any tutorial I’ve done that doesn’t involve using it. What exactly is Raspbian, though? It’s Linux, correct?
Yes! Raspbian is based on Debian, which is a Linux distribution. It’s called Raspbian because it’s a portmanteau of Raspberry and Debian; much in the same way as RaspBMC or Pidora.
That answers part of my question, but could you elaborate more on the Debian bit in particular?
Debian is a line of quite popular Linux distributions that is the base of many famous distros; Ubuntu and its offshoots, Tails, SteamOS, wattOS and many more. It’s very easy to use and contains a large repository of software, so it’s easy to extend and customise it exactly how you want it.
You keep calling it a Linux distribution, which seems oddly specific. What does that mean?
The different versions of Linux are called distributions or distros. They take the Linux kernel and its other technologies and package it with their own software, software repositories, branding and perhaps even a desktop environment. Debian is an example of one of these distros.
What sort of software makes it stand out as Debian specifically?
There’s not a huge amount, to be perfectly honest – and neither is that majorly important unless you’re into the really low-level security and behind-the-scenes workings. What you will notice is its package management system, Aptitude, which is a major part of Debian and its various flavours and offshoots – if you’ve used sudo apt-get anywhere in a tutorial, this is it. There’s also stuff like the way boot time programs are loaded and some necessary tools for compiling software, but you won’t often come across it.
So is Linux an operating system?
That’s the $64,000 question. The short answer is no but that doesn’t really explain why it’s not. Linux is a kernel, which, while a core part of any operating system, does not make up the entire operating system. There are various tools that come with the kernel via the GNU project (the reason why it’s sometimes called GNU/Linux) which bring it up to a level more akin to an operating system – but it’s not quite there yet. You could technically say that these distributions as a product on their own are part of an operating system – eg Raspbian is an OS for the Raspberry Pi – however, in doing so you run into other issues, such as the stuff making up Raspbian being extra components on top of the Linux kernel and GNU tools which wouldn’t make up an operating system on its own either.
If someone asks you if Raspbian is an operating system, though, just say yes. You’ll keep more friends that way.
That’s a little bit mind-boggling but I think I understand. So if Raspbian is a version of Debian, is there ‘pure’ Debian on Raspberry Pi?
Yes there is. In fact, there was Debian for Raspberry Pi before there was Raspbian. It was the version specifically designed for the CPU that the Raspberry Pi uses, as not every Linux distro has a version that will run on Raspberry Pi.
Isn’t the Raspberry Pi running on ARM? I thought there were other operating systems that ran on ARM?
Yes, there are ARM versions of Ubuntu and even Windows right now, however they’re for different versions of ARM. The Raspberry Pi uses ARM v6, while Ubuntu specifically uses a newer version. There are also special tools that make better use of the Raspberry Pi hardware and are integrated into the major Raspberry Pi distros.
So if Raspbian is based on Debian, does that mean there are other distros based on Raspbian?
The Kano OS that we review in this issue (pages 12-13) is based on Raspbian – and there are maybe a couple of others that are minor changes on Raspbian. Still, mostly the other Debian-based Pi distros are actually purely based off of Debian, such as RaspBMC the XBMC Pi distro.
So why is it that Raspbian has become the default distro for the Raspberry Pi, then?
It’s mostly down to luck and good timing, really. A couple of years ago there was a Fedora spin that was being touted as the official Raspberry Pi distro, however there were some major problems with it. The project that became Raspbian ended up being chosen as a preferred distro around that time and the community really latched onto it. Since then, all the major Raspberry Pi Foundation announcements regarding software have involved Raspbian and pretty much all shared community projects are done on Raspbian, which is why we do a lot of our projects on it as well.
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