In one hand i have general daily linux: Fedora/CentOS/ArchLinux/Ubuntu. On other hand i have following:

  • eCos
  • FreeRTOS
  • BuildRoot
  • openembedded
  • uCLinux

Did anyone used those uncommon linux distro's often, where do they best suite for (server or desktop use or for nonstop services)?

Are they completely different then our general linux?

  • 2
    ecos is not a linux distribution. it does not run the linux kernel Jun 19, 2012 at 17:21
  • The eCos web page says that "eCos is not related to the Linux operating system", so comparing it with Linux distributions is like comparing Windows CE with Fedora. Jun 19, 2012 at 18:32
  • Ditto for many of the others mentioned. OTOH, I use my Android phone frequently... and wouldn't compare it to my day-in day-out Fedoras --- just too different.
    – vonbrand
    Jan 18, 2013 at 2:10

1 Answer 1


You seem to make the (common) assumption that computers can either be a desktop or a server.

There are a lot of other devices that run Linux/Unix around you:

  • cars/trains/planes/...
  • Tivo
  • phones, tablets and other gadgets.
  • a watch
  • ...

The requirements for running Linux on these platforms are fundamentally different from what your PC may be used to. Therefore, different distros are leaders on these markets.

Fedora, Ubuntu, CentOS, ArchLinux are direct competitors in the sense that, while they do things slightly differently, they are still targeting your PC and/or your server. In a slightly technical term, they are targeting the x86 architecture. (I believe these distros won't even support any other CPU architecture).

The other distros have different targets altogether. I can separate the examples you give into 2 categories:

From your list: RTEMS, FreeRTOS, eCos.

A kind of operating system that treats the time variable a bit differently. It is my understanding they run in environments where delays and bottlenecks are not tolerated. A common example would be a breaking system in a car.

From your list: uClinux, Openembedded, Buildroot (Note that the latter is not a real distribution, rather a building environment.)

These operating systems target a wide variety of platforms and architectures. They are popular among the electronics/microcontroller crowd, where traditionally resources are scarce, and cross-compilation is very common.

To make things simple, think of the examples you mention as highly specialized distributions that do very specific tasks. It goes to attest to the wide range of domains the Linux kernel can cover and what are the kinds of challenges the people in the kernel development team have to face.

  • Nitpicking: Fedora, Ubuntu, Centos and ArchLinux don't just support x86. They also support AMD64, aka EM64T, aka x86_64 which is very much not the same as x86. ;)
    – Alexios
    Jun 19, 2012 at 19:19
  • Oh yes, I thought about mentioning it. But I was making a slightly different point. x84 and amd64, while different architectures, are generally used in the same machines: desktop PC and servers. So, only in the context of my answer, I felt they were similar. Maybe I should change that.
    – rahmu
    Jun 19, 2012 at 20:54
  • @rahmu: Nice answer. Does it mean Arduino or Crestron/Extron is in categories of your point 1. Another confusion starts now. What is Linux RT Kernel vs FreeRTOS or eCos then? (Can Linux RT kernel be not same as eCos or FreeRTOS?)
    – user11085
    Jun 20, 2012 at 6:58
  • You seem to be making the (also common) assumption that every OS that isn't Windows is Linux. Why is that? As mentioned before "eCos is not related to the Linux operating system". Why are you struggling with this?
    – rahmu
    Jun 20, 2012 at 8:59
  • 1
    @YumYumYum RT doesn't mean it has to be fast but that something has to happen until a specific time, e.g. every 10ms. If you look closely at the projects you see that they are different and not equals. And regarding your NASA point, the programming language of your application(s) has nothing to do with the operating system. I just googled and found weblog.cenriqueortiz.com/computing/2007/08/18/… it seems NASA is using it's own OS which makes much more sense than using linux. Please don't spread FUD and inform yourself. Jun 21, 2012 at 7:38

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