Operating system support for adaptive distributed real-time systems in DRAGON SLAYER

1989 ◽  
Vol 23 (3) ◽  
pp. 126-140 ◽  
Author(s):  
H. F. Wedde ◽  
G. S. Alijani ◽  
W. G. Brown ◽  
S. Chen ◽  
G. Kang
Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3346
Author(s):  
Mahmoud Hussein ◽  
Ahmed I. Galal ◽  
Emad Abd-Elrahman ◽  
Mohamed Zorkany

IoT-based applications operate in a client–server architecture, which requires a specific communication protocol. This protocol is used to establish the client–server communication model, allowing all clients of the system to perform specific tasks through internet communications. Many data communication protocols for the Internet of Things are used by IoT platforms, including message queuing telemetry transport (MQTT), advanced message queuing protocol (AMQP), MQTT for sensor networks (MQTT-SN), data distribution service (DDS), constrained application protocol (CoAP), and simple object access protocol (SOAP). These protocols only support single-topic messaging. Thus, in this work, an IoT message protocol that supports multi-topic messaging is proposed. This protocol will add a simple “brain” for IoT platforms in order to realize an intelligent IoT architecture. Moreover, it will enhance the traffic throughput by reducing the overheads of messages and the delay of multi-topic messaging. Most current IoT applications depend on real-time systems. Therefore, an RTOS (real-time operating system) as a famous OS (operating system) is used for the embedded systems to provide the constraints of real-time features, as required by these real-time systems. Using RTOS for IoT applications adds important features to the system, including reliability. Many of the undertaken research works into IoT platforms have only focused on specific applications; they did not deal with the real-time constraints under a real-time system umbrella. In this work, the design of the multi-topic IoT protocol and platform is implemented for real-time systems and also for general-purpose applications; this platform depends on the proposed multi-topic communication protocol, which is implemented here to show its functionality and effectiveness over similar protocols.


Author(s):  
Sanjay Singh ◽  
Nishant Tripathi ◽  
Anil Kumar Chaudhary ◽  
Mahesh Kumar Singh

RTOS (real time operating system) can be defined as “The ability of the operating system to provide a required level of service in bounded response time.” A real time system responds in a (timely) predictable way to unpredictable external stimuli arrivals. To build a predictable system, all its components (hardware & software) should enable this requirement to be fulfilled. Traffic on a bus for example should take place in a way allowing all events to be managed within the prescribe time limit. However it should not be forgotten that a good RTOS is only is building block. Using it in a wrongly designed system may lead to a malfunctioning of the RT system. A good RTOS can be defined as one that has a bounded (predictable) behavior under all system load scenarios (simultaneous interrupts and thread execution). In RT system, each individual deadline should be met. Real-time systems are designed to control and monitor their environment. Most of these systems are using sensors to collect environment state and use actuators to change something.


Author(s):  
SHAKTIRAJ KUMAR CHAGANTY ◽  
B. LAVAN ◽  
DR.S.SIVA PRASAD

A real-time microkernel is the near-minimum amount of software that can provide the mechanisms needed to implement a real-time operating system. Real-time systems are those systems whose response is deterministic in time. In our research a 32-task Real Time Microkernel is designed using which multi tasking can be done on the targeted processor ARM7TDMI. Two sets of functions are developed in this research work. First one is Operating System functions and second is application functions. Operating System functions are mainly for carrying out task creation, multi-tasking, scheduling, context switching and Inter task communication. The process of scheduling and switching the CPU (Central Processing Unit) between several tasks is illustrated in this paper. The number of application functions can vary between 1 to 32. Each of these application functions is created as a task by the microkernel and scheduled by the pre-emptive priority scheduler. Multi tasking of these application tasks is demonstrated in this paper.


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