Real-time POSIX? - Embedded

This is a discussion on Real-time POSIX? - Embedded ; Hello, I would appreciate any information regarding the compliance/conformance of Linux to the POSIX real-time specifications. Which distributions or kernel patches do add real-time to the vanilla kernel those days? How much do they comply with RT POSIX extensions, and ...

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Thread: Real-time POSIX?

  1. Real-time POSIX?

    Hello,

    I would appreciate any information regarding the compliance/conformance of
    Linux to the POSIX real-time specifications.

    Which distributions or kernel patches do add real-time to the vanilla kernel
    those days? How much do they comply with RT POSIX extensions, and with
    which ones exactly? Which distros claim hard RT?

    Thanks
    a.



  2. Re: Real-time POSIX?

    A. Melinte wrote:

    > I would appreciate any information regarding the compliance/conformance of
    > Linux to the POSIX real-time specifications.
    >
    > Which distributions or kernel patches do add real-time to the vanilla kernel
    > those days? How much do they comply with RT POSIX extensions, and with
    > which ones exactly? Which distros claim hard RT?


    I'm not sure, but I think this is a start:
    http://www.tglx.de/hrtimers.html

    Am I mistaken?

  3. Re: Real-time POSIX?

    "A. Melinte" wrote:
    >I would appreciate any information regarding the compliance/conformance of
    >Linux to the POSIX real-time specifications.
    >
    >Which distributions or kernel patches do add real-time to the vanilla kernel
    >those days? How much do they comply with RT POSIX extensions, and with
    >which ones exactly? Which distros claim hard RT?


    Claiming "some real time", no necessarily "hard":

    KURT: http://www.ittc.ku.edu/kurt/
    Timesys: http://www.timesys.com
    Lynx/Linuxworks: http://www.linuxworks.com
    Montavista: http://www.mvista.com/
    Montavista: http://source.mvista.com/linux_2_6_RT.html

    Information: http://www.realtimelinuxfoundation.org/

  4. Re: Real-time POSIX?

    Hi,

    A. Melinte wrote:
    > Hello,
    >
    > I would appreciate any information regarding the compliance/conformance of
    > Linux to the POSIX real-time specifications.
    >
    > Which distributions or kernel patches do add real-time to the vanilla kernel
    > those days? How much do they comply with RT POSIX extensions, and with
    > which ones exactly? Which distros claim hard RT?
    >
    > Thanks
    > a.


    RTLinux (Pro), RTLinux Free, RTAI are all hard POSIX compliant
    Linux-based OSes.


  5. Re: Real-time POSIX?

    > Which distributions or kernel patches do add real-time to the vanilla kernel
    > those days? How much do they comply with RT POSIX extensions, and with
    > which ones exactly? Which distros claim hard RT?


    As Linux can't do _hard_ realtime at all, every distro is very far away.
    _Soft_ realtime is another thing. A 2.6 Kernel on a CPU that is
    appropriately fast for the project in question might be quite good.

    AFAIK, Pike OS (a not free add-on to Linux by SysGo) offers a realtime
    Posix API.

    -Michael

  6. Re: Real-time POSIX?

    raseelbhagat@gmail.com wrote:

    > Hi,
    >
    > A. Melinte wrote:
    >> Hello,
    >>
    >> I would appreciate any information regarding the compliance/conformance
    >> of Linux to the POSIX real-time specifications.
    >>
    >> Which distributions or kernel patches do add real-time to the vanilla
    >> kernel
    >> those days? How much do they comply with RT POSIX extensions, and with
    >> which ones exactly? Which distros claim hard RT?
    >>
    >> Thanks
    >> a.

    >
    > RTLinux (Pro), RTLinux Free, RTAI are all hard POSIX compliant
    > Linux-based OSes.

    RTLinux(Pro) is NOT free.
    RTLinux Free is only available for kernel 2.4
    A more up to date and free hard RT (even in user space) extension for Linux
    kernel 2.4 and 2.6 with several "RT-skins" (e.g.: PSOS, VRTX, POSIX) is
    XENOMAI
    see: www.xenomai.org


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