What is RTOS and how do I know that I need one?

[cmos babe]

introduction to rtos

I've done many micrcontroller-based projects but ive never felt that I ned an RTOS maybe because i have no idea what it is can some explain to me when they are used ? and can you recommend some good books for a newbie like me.
thanks in advance

 

[trend]

need for rtos

RTOS - real time operating system

Added after 2 minutes:

Well, at the very basic level.. it just allows the MCU to multitask.

But, many RTOS add extra features/drivers to the game.. (lets take for example using a ver of linux as a RTOS, it might come with drivers for an ethernet chip)

Added after 1 minutes:

Try searching the forum... here is one of the first links I found:

 

[firmy]

rtos concepts pdf

One major need for an RTOS is if you have to execute multiple threads ...writing a schedular in C to make other threads than the usual main() to run in parallel is made much simpler if you have a real time operating system doing the job for you, and the fact that it is real-time comes with many timing assurances....
-F

 

[muruga86]

what is rtos

the need for RTOS araises when a complex project of many modules showl be controlled without one module interfering with data of another module.


check this site
www.mnis.fr/en/support/doc/rtos/

 

[asemnor]

simple rtos code in c++

A RTOS(Real time operating system) is needed when programminf multiple threads.I guess the reasn you di not use one has to do with co-design.Building systems using microcontrollers almost always give the programmer unlimited access to system components hence a RTOS in not needed.

 

[swapgo]

rtos concepts

Hi,

First try to understand the RTOS concepts first. and try to implement some simple RTOSs.

To understand the RTOS concepts U can find the book in this forum itself.

The book is in chm format.

"CMP.Books.Real-Time.Concepts.For.Embedded.Systems.eBook-LiB.chm" is the name of the file. You can search in the E-books upload and download section.

After getting an excellent introduction to the RTOS now try an RTOS to implement in your own Microcontroller based projects.

Remember adding RTOS always adds overhead to the system.
But if you have more memory and the performance is the main concern then try it out.

I suggest UCOS-II RTOS . Its preemptive and very sleek RTOS, Ideal for Microcontrollers. You can get the book from amazon and it comes with source code for the RTOS. The code is well documented. U can understand the RTOS better and its internal architecture also. There are ports for microcontrollers available in their website. U can download them and try them out.

Understand RTOS is simply a setof routines which can handel more functionality in the project with ease.

Have fun

Regards
Gopi

Added after 33 minutes:

the need for RTOS araises when a complex project of many modules showl be controlled without one module interfering with data of another module.


check this site
www.mnis.fr/en/support/doc/rtos/

U mean the concept of C++.

In C++ the data can be clearly encapsulated.

But RTOS is something beyond.

The time is critical here. Thats why its called as Real-Time Operating Systems.

So RTOS to explain in your words "Complex Project with more modules and the entire project managed to execute in a predicted manner"

Regards
Gopi

 

[caliph]

mucos rtos example

Need for an RTOS depends on the type of application. If the system has a single task to do then probably it shall be very simple and may not even require any OS. But the moment you bring in multiple tasks and an ability to share data between these tasks, then an RTOS becomes a necessity. An RTOS provides you services that you would need in order to spawn tasks, share data between them, prioritize them and in addition it shall guarantee you that the tasking overheads shall be predictable and constant (and very less, of course). Further, you have certain add-on's thrown in like networking support and so on. So the need for an RTOS really depends on the application.

Now the question: how do I know that I need one?
Simple rule of thumb is: if you find yourself creating a sort of scheduler to schedule various activities that your application needs to perform, then you definitely need an RTOS.

 

[amjad]

when do i need an rtos

when you feel
1. number of resources concerned is more
2. chances of strcuking in one when other resources may get missed or delayed chances(like display segments flickers when u take more time in some routines and delayed the refreshing)
3. chances datas getting corrupted or mishandled between routines.( like interrupt changes data when some routine using that same data for some operation)
then it is time to think about RTOS.

Using RTOS
u can manages the resources the way u like , by prioritising and scheduling.
you can handle datas in secured manner .
different tasks can be communicates with one another using messages and signals.

 

[leomecma]

rtos dubai

Please, anyone have the files of uC/OSII source code. Please anyone can send it to me? I just study how it works, but I don't have money to buy the book.

Added after 17 minutes:

Anyone have used any OS with TMS470? Which? Please help me....

 

[helios]

simple real time operating system book india

hai dude

get the source code of mucos from **broken link removed**

and there are very less turorials in net for ucos ... i have spent a lot of time searching for it and i found a execelent set of pdf ...

you dont need that book at all ... this pdf,s is more than suffcient to start with mucos II.....

http://www.csie.ntu.edu.tw/~d6526009/ucOS2/

this link also has the mucos source code

let me know if it helped you