Real Time Operating System or RTOS is an operating system with additional real time functions for adherence to time constraints and predictability of process. The main ingredient of such a specialized Real Time Operating System (RTOS) is real-time operating system kernel or in short real-time kernel. We wrote about Kernel in a separate article.
Requirements to be Real Time Operating System for an Operating System
Even popular desktop operating systems are not able to guarantee a soft real-time performance for high-priority processes and may not accurately predictable by in terms of response time for swapping , handling hardware interruption etc. and in worst they do not guarantee hard real-time behavior.
Real Time Operating System must be able to guarantee so that even in the worst case, it works in defined response times. This concern is mainly in the areas of scheduling and memory management. Real Time Operating System also supports additional error detection mechanisms.
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The usually deploy Micro kernel, Nano kernel and more smaller kernels. Various Algorithms are used for Real Time Operating System.
Where we use Real Time Operating System

Real Time Operating System are typically use in surgical robotics. The reason is that, we need instant work. There are many inventors working with modular interactive computer assisted surgery where Real Time Operating System is a great enhancement in work field.
Real Time Operating System can perform Real Time Multi Tasking. In mission critical processes, like for a Country’s automated surveillance, Auto Pilot system Real Time Operating System plays a good role.
These are alphabetical list of Real Time Operating System, most are active, some might have been closed :
- ADwin
- BeRTOS
- ChorusOS
- CMX-RTX
- eCos
- FreeRTOS
- Libertos
- LynxOS
- MicroC
- OS-MMU
- On Time RTOS-32
- OS-9
- Palm OS
- PikeOS
- PowerPac
- QNX
- Real-Time Executive
- Real VMX Clone
- RT-11
- RTAI (real time extension for Linux)
- RTEMS
- RTLinux
- RTOS-UH
- RTOSVisor
- SCIOPTA RTOS
- SMX RTOS
- TTP-OS
- VxWorks
- Windows CE
