Thoth, a portable real-time operating system

2001

finished. It is possible to avoid the problem by adding break points to the event handling code where the handling of urgent events can take place. On the other hand, the problem is not critical, if a powerful processor is available. The real-time properties of most embedded systems are based on the use of real-time operating systems. Application of such operating systems requires high expertise and much time. The resulting software is often heavy and hard to maintain. In this paper we present a class of application specific operating systems called ReaGOS. ReaGOS is based on a new architecture and an operating principle, where the operating system calls application programs but not vice versa. The new architecture saves both data and code memory and it is fast enough for embedded systems. The operating system is generated automatically from a high level graphical specification. Another method uses interrupt mechanisms to handle I/O driver events [5]. This method has some disadvanta...

Embedded Systems - Theory and Design Methodology, 2012

Real-Time Operating Systems and Programming Languages for Embedded Systems hardware architecture, as it is the case of RTSJ. This is undoubtedly a new scenario in the development of embedded real time systems. There is a wide range of hardware possibilities in the market (microcontrollers, microprocessors and DSPs); also there are many different programming languages, like C, C++, C#, Java, Ada; and there are more than forty real-time operating systems (RTOS) like RT-Linux, Windows Embedded or FreeRTOS. This chapter offers a road-map for the design of real-time embedded systems evaluating the pros and cons of the different programming languages and operating systems. Organization: This chapter is organized in the following way. Section 2 describes the main characteristics that a real-time operating system should have. Section 3 discusses the scope of some of the more well known RTOSs. Section 4 introduces the languages used for real-time programming and compares the main characteristics. Section 5 presents and compares different alternatives for the implementation of real-time Java. Finally, Section 6 concludes.

Real-time Systems, 1999

This paper describes an open system architecture that allows independently developed hard real-time applications to run together and supports their reconfiguration at run-time. In the open system, each real-time application is executed by a server. At the lower level, the OS scheduler schedules all the servers on the EDF basis. At the upper level, the server scheduler of each server schedules the ready jobs of the application executed by the server according to the algorithm chosen for the application. The paper describes the two-level CPU scheduling scheme used by the open system and the design and implementation of a uniprocessor open system within the framework of the Windows NT operating system. The implementation consists of three key components: the two-level hierarchical kernel scheduler, common system service providers, and real-time application programming interface.

Journal of Communication and Computer, 2015

Since their early applications in the 1960s, embedded systems have come down in price and increased dramatically in processing power and functionality. In addition, embedded systems are becoming increasingly complex. High-end devices, such as mobile phones, PDAs, entertainment devices, and set-top boxes, feature millions of lines of code with varying degrees of assurance of correctness. Nowadays, more and more embedded systems are implementing in a distributed way, and a wide range of high-performance distributed embedded systems have been design and deployed. As many aspects of embedded system design become increasingly dependent on the effective interaction of distributed processors, it is clear that much effort needs to be focus on software infrastructure, such as operating systems, to ensure that they provide functionality to fulfill these requirements. This paper reviews some of the approaches associated with the operating systems used to fulfill these needs.

Advanced PIC Microcontroller Projects in C, 2008

Annual Review in Automatic Programming, 1981

The operating system kernel of a multiprocessor system based on 16 bit microcomputers is described. The multiprocessor system constitutes a node of a local computer network dedicated to the control of continuous or discontinuous industrial processes. The kernel makes available a virtual machine where processes allocatedon dif ferent processors are executed in parallel, while processes which reside on the same processor are executed in a multitasking environment. The processes can cooperate by means of synchronization and message passing primitives; furthermore they can interact by means of short-term scheduling primitives which perform the creation, destruction, activation and termination of a process. The interprocessor communication mechanisms allow the primitives to make all the process interactions transparent to the physical allocation of the interacting processes. The system has been completely implemented in the PASCAL language, excepting only few functions of the lowest level, coded in the assembler language. The distributed kernel has been developed and tested on a conventional machine (a DEC PDP11/34 computer under RSXll-M Operating System). The processes allocated on the same processor have been implemented as a sil gle RSXll task, and interprocessor communications have been simulated by means of intertask system primitives.

IFAC Proceedings Volumes, 1979

Two dedicated real-time operating systems (RTOS) are analysed and compared with logical model obtained in TC-8, Purdue Europe. Specialisation is mainly concentrated to Process Management, Exception Handling and operator-RTOS interface. It is concluded that dedicated RTOS, absolutely necessary in some cases, has in all applications certain advantag e s. Consequently, the possibility to dedicate an ope rating system should be considered as an essential RTOS design problem.

EURASIP Journal on Embedded Systems, 2008

The rapid progress in processor and sensor technology combined with the expanding diversity of application fields is placing enormous demands on the facilities that an embedded operating system must provide.

IFAC Proceedings Volumes, 1990

2006

Tanenbaum's MINIX Operating System was extended with a Real-Time microkernel and services to conform MINIX4RT, a Real-Time Operating System for academic uses that includes more flexible Interprocess Communications facilities supporting Basic Priority Inheritance Protocol, a fixed priority scheduler, timer and event driven interrupt management, statistics and Real-Time metrics gathering keeping backward compatibility with standard MINIX versions.