Is there big difference between RTOS and Embedded Linux

[tvnaidu]

Porting small application from windows to embedded system, not decided what to use whether RTOS or Embedded Linux, is there big difference between RTOS and embedded Linux?.

also I need to reduce the C code size (during development all debugging symbols are visible), for final product, I don't need all debugging symbols, I need to turn off all those symbols, can I reduce code size for final product?.

also I have to write a library which should be replacable during run time, I am thinking of develop shared library, this way I can replace this at run time instead of power cycle the device, just upload shared library and bringdown the process and bringup process again, can I do with shared library. Thanks.

[Banfa]

An RTOS is much more lightweight than embedded Linux.

Normally an RTOS consists of a single process with threads, where Linux is multi-process.

An RTOS has no concept of kernel mode, all sections of code have access to all parts of the system.

An RTOS is normally in a single statically linked executable file, there is no option for shared libraries.

An RTOS rarely includes all the features, disk access, IO devices, USB stack, Network stack etc that are in Linux, these normally have to be bolted on.

[tvnaidu]

Thanks Banfa.

How can I select whether to use RTOS or Embedded Linux?. Looklike Embedded Linux needs high-end Processors, where as RTOS doesn't, high-end processors are expensive, is embedded Linux better performance than RTOS?.

any other OS features (lock, protection) advantages in RTOS than Embedded Linux?

[tvnaidu]

Is RTOS is non-preemtive?. Is low priority process gets thrown out when higher priority process needs CPU resources?. where as in embedded linux is pre-emtive?.

[Banfa]

Whether any OS RTOS or not is preemtive or not is entirely down to the OS design. I have seen preemtive and non-preemtive RTOS and time sliced and co-operative ones too.

Linux is preemtive and I assume embedded Linux is too.

As you say RTOS run on much lower-end processors than embedded Linux, I can not say if your application is suited to a low-end processor with an RTOS say a 16 bit micro-controller as opposed to a medium(?)-end processor running embedded-Linux, an ARM say.