In past years, the market of Operating Systems (OS) has been quite active. One of those key markets is to support embedded real-time applications in which the OS must guarantee the timeliness as well as the correctness of the processing. Many OS claim to be Real-Time Operating Systems (RTOS), but often, it is only by reviewing the OS specifications or detailed information that one can truly identify the OS that enables realtime applications.
A realtime system is one in which the correctness of the computations not only depends upon the logical correctness of the computation but also upon the time at which the result is produced. The term real-time has evolved to refer to any application in which a computer is used to control a process. Machine control; robotics; data acquisition and display; communications; telephone systems; automotive control systems; factory automation and instrumentation systems are a few examples. Nowadays, RTOS are quite large and complex pieces of software that provide a variety of services. Services include embedded applications, network communications, file systems management, distributed systems management, redundancy management, and dynamic loading of application software.
Real time is an often misunderstood — and misapplied — property of operating systems. Matching a commercial real-time operating system to a particular application is a problem for which there is no obvious strategy. Technical factors such as estimated production volume, likely processor involved, mission criticality, cost, reliability, software support, ease-of-use, and maintainability need to be considered.
In this report, I will attempt to provide a summary of some of the critical elements of realtime computing. A comprehensive study is done on existing commercial real-time operating systems. The contribution of this research oriented paper to illustrate the characteristics of a good RTOS and to compare the various commercial RTOS. This paper also examines techniques that can be found in General Purpose Operating Systems (GPOS) and explain why they can or cannot be used in real-time operating systems. The objective of this work package is to make a study of the state of the art of real-time technology and to determine what types of mechanisms actually turn out to be most useful for real-time applications.
In concrete, this report will analyse the real-time operating systems (RTOS) features and extract the main characteristics of different commercially available RTOS like windows CE, Vx WORKS and QNX and based on these facts comparative study of the different commercially used RTOS are done. The report is to produce and analyse prototypes of various innovative real-time techniques, like scheduling, resource management, fault-tolerance and communication with real-time constraints, which are identified as the key elements to provide predictable and high performance distributed real-time operating systems.
