Re: difference between RTOS and LInux os

[sudheer <urwithsudheer@xxxxxxxxx>]

Hi MHD.Tayseer Alquoatli,

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in other words, will non-deterministic operations on linux still be non-deterministic when running RTLinux ?
by the way, can anybody give examples of non-deterministic operation in Linux kernel that are not cause of a non-deterministic nature of the hardware
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To my knowledge, RTkernel takes or executes only the real-time activities. all the non-rt activities will be assigned to normal kernel like accesing data from files , etc when no rt task are ready to run.

And so  i dont think , we can listen to songs( say a non-real-time activity) parallely in RTlinux while running real-time activities .
Accessing data from harddisks , writing data to files are non-determenistic.
eg: Data recieved from sensors will be stored in buffers - real-time (rtkernel)
     Data from  buffers to files is nrt activity . (normal kernel)
Programmer s'd take care to give sufficient time for nrt activities also.

Thanks
Sudheer.A

MHD.Tayseer Alquoatli wrote:

Hi All:

Ashok kumar wrote:

can any one tell clear idea or provide link to know about difference between RTOS like RTLinux and GNU/Linux os.

the main difference is the determinism property which is:
"Each operation must be guaranteed to finish executing within a pre-determined period of time".
such a guarantee is only provided by RTOSes.

On 4/10/06, sudheer <urwithsudheer@xxxxxxxxx> wrote:

Hello Ashok,

I have some basic knowledge in RTLIinux and lets share.

RT-Linux is an os in which the rtkernel co-exist along with the normal kernel.  The normal linux kernel runs as a non-real time application and is made to run when no real-time activites are ready to run.  All the real-time activities  run in  rtkernl and non real-time  activiteis (user applications) in the normal kernel.  An interrupt emulation layer exist in b'n the two kernels.. All the interrupts are initailly recieved by the rtkernel, &  interrupts related to non  real-time kernel are passed to it normal kernel  by rtkernl  when no rt activities to run.

does this mean that RTLinux design doesn't offer linux kernel services in real time, but instead it offers linux capabilities when no RT is needed along with the RT services offered by the RT kernel which linux kernel runs over ?

in other words, will non-deterministic operations on linux still be non-deterministic when running RTLinux ?
by the way, can anybody give examples of non-deterministic operation in Linux kernel that are not cause of a non-deterministic nature of the hardware behind it like hard disks or Ethernet network interface?
Thanks

MHD.Tayseer

plz  find few links below:
rtlinux.lzu.edu.cn/documents.html
pficheux.free.fr/eyrolles/linux_embarque/ docs_externes/rtl_GettingStarted.pdf

But the architecture of the other RTOSs  may be different from  RTLinux.  In common  Real-Time Kernels are preemptive.

Anyone can correct me if i am mistaken.


Thanks
Sudheer