What is a RTOS in embedded system?

Any body cud pls explain me what is rtos in embedded systems and products. I am building a project which includes avr atmega series microcontroller and the project requires input from finger print scanner i.e I want a certain window or options to be open on tft lcd according to the input from finger print scanner.Does it requires building an RTOS via controller.
Please suggest me something

Re: What is RTOS in embedded system n how it is build in the end product?

With little 8 bit uC like the AVR, an RTOS is not necessary. A runtime "while" loop works well.. you can choose to use interrupt handlers to capture and tag quick events, and use the run time loop not in the interrupt context to process the event.

Re: What is RTOS in embedded system n how it is build in the end product?

Depends upon the final requirement of your application.

but most of the time RTOS is not required in many of small applications.

if all you want to do is read a finger print scanner and show an options window than probably you will not require an RTOS.

but if your application starts to build up to complex options, communications, interactions; so that you need to divide some tasks and implement them in seperate than you may need an RTOS.

Re: What is RTOS in embedded system n how it is build in the end product?

RTOS stands for (real time operating system) , i don't have a good experience with them ,
but generally they are small operating systems for micro-controllers ,
like other operating systems they allow you to run many functions in parallel just like windows runs chrome and VLC media player (apparently) in the same time ,
unlike windows this system doesn't lag , because it's designed to preform your tasks at specific sharp timing that's why it's called (real time)

as the adelmon and bsprajc said rtos aren't usually needed in simple applications , it's needed when you need your code to make a lot of tasks in the same time like (handling interfaces , reading inputs , managing communication , implementing some complex protocol or encryption )

Re: What is RTOS in embedded system n how it is build in the end product?

Your application is very simple and it doesn't require RTOS. If you have multiple tasks running in your system and if you want to configure them based on priority, scheduling and so on.,then you can go for RTOS.

Re: What is RTOS in embedded system n how it is build in the end product?

From the minimal description of your project an RTOS would not be required.

However, if you are interested in learning about RTOS or schedulers, one of the finest texts covering topic is Michael J. Pont's:

Patterns for Time-Triggered Embedded Systems

Although it has been out-of-print for a number of years and used copies are selling for a small fortune, Michael has generously made the text freely available in PDF form and downloadable from his website.

Not only can the text provide insight into the internals of an RTOS, it can instruct you on the process of "rolling" your own.

While the code in the original text was written for the 8051 series of microcontrollers, it certainly can be ported to almost any other microcontroller and ports are already available for several.


BigDog

Re: What is RTOS in embedded system n how it is build in the end product?

Thank you guys for your prompt replies......
Actually let me describe my project in brief
I want to build a portable device like tablets which will work as attendance management system in colleges/universities based on fingerprint recognition of students.
Firstly It requires an admin to open the device by their fingerprint (which ofcourse will be faculty) and then it will display a window on Tft lcd with the schedule of the faculty(like time table) on opening a particular session the students are required to scan their finger(which has already been saved in system) for matching and marking attendance
This is what i envision..So does it requires RTOS?????????

Re: What is RTOS in embedded system n how it is build in the end product?

I don't think you need RTOS, and learning a RTOS is typically a time consuming task, even if you are already familiar with micro-controller itself. But as adelmon and bsprajc and evilheart said, If you need multiple task running at the same time its a good idea to implement your project on top of a RTOS. managing an rtos project fairly is easier. and if u like to add some features in future like networking...its better to go with rtos system. hope it helps

RTOS - Real Time Operating System

RTOS are time bounded systems, that is, systems that have to work in specific time frame with no buffers.
I would like to explain this with an example.
Suppose you are watching High Definition TV show, how would you react if you get Audio before Video, or Video before Audio?
You would want the very high quality along with the good sound quality.
For that the HDTV system has to complete the task of converting the video and audio input and display it in a specific time frame.

Further, there are hard real time operating systems and soft real time operating system.

There is no time frame is it? The finger print scanning can be done anytime, after a second or after a minute after the professor's fingerprint scanning. So, I am doubtful if you really require a RTOS system.