Abstract

The purpose of the work is to analyze the features and functioning of the RTS, RT operating systems (RTOS) and the development of applied programs (AP) for RTS; RTS standards; characteristics and analysis of the RTOS; problems of extensions of RT based on Linux and Windows. The main differences between the RTOS and the general purpose OS are shown: the main task is to have time to react to events at the site; an RTOS is a tool for creating a specific SRT. The following characteristic functions of RTOS are distinguished: multitasking with preemption; realizing priorities for threads; predictable synchronization mechanisms; providing inheritance of priorities; behavior is known and predictable; for all scenarios of the STR the maximum response time is determined. It is shown that the processing of events in SRT depends on the field of application and hardware; events are reported via IRQ, so the key parameter is the response time of the interrupt latency. There is no generally accepted method for determining this parameter, but it can be predicted/ computed. The reaction time for an event is calculated by the value of its components, taking into account the worst situation for the SRT (the microprocessor is loaded, and actions that block interrupts). The evaluation of response times to the interruption of the RTOS is performed based on the data of the target SRT testing. Estimating the processing time for parallel events is determined by the context switching time. It was noted that the RTOSRTS is running on industrial computers in connection with which the RTOS should work in diskless execution, support, as much as possible, the microprocessor and types of special equipment, have tools for creating and debugging AP. The RTS standards (POSIX, DO-178A/ B/ C, ARINC-653, ED-12B, OSEK/ VDX (OSEK), SCEPTRE, TCSEC, etc.) are analyzed, their characteristics are given and it is shown that the importance of standards is that they are an axiomatic basis that defines the definitions of objects and concepts. It is shown that, from the point of view of the programmer, "Common Criteria ..." can be considered as a set of libraries which helps to write the tasks on security, typical security profiles, etc. Such properties of common RTOS are considered: POSIX compliance; rapidity and efficiency; they are modular and scalable; they support two-stage interrupt processing, have planning schemes, high resolution timers and counters; there are mechanisms for swapping and protecting memory; tasks and the kernel are executed in a single address space; correspond to Host-Target or SelfHosted. The analysis of the RTOS (CHORUS; LynxOS; OS-9; pSOS; RTC; VRTX; VxWorks; QNX, etc.) is presented in the format: name, main characteristics: type; architecture; standard; Properties as RTOS; operating system (host); processors (target); communication lines host-target; the minimum size; means of synchronization and interaction; development tools. The problems of adaptation to the requirements of the RT are considered. It is shown that the adaptation of Linux to the requirements of the RT is carried out in such directions: in accordance with the POSIX standard; the support of special hardware, running Linux from ROM, the resolution increase of the system timer; implementation of the preemption mechanism for the kernel. There are two ways to implement preemption for the Linux kernel: to rewrite the kernel, to implement the mechanism of preemption as a microcoder for scheduling interrupts and tasks. W’NT adaptation, based on the elements of the RT, was carried out in two ways: (1) the use of the conventional RTOS core as an addition to the core W’NT (the technology of using two OS on one computer); (2) PB integrating into W’NT by avoiding delays and hangs with the help of the RT extensions. The use of digital technologies in the aviation and space industry raises the need for training specialists, which in turn requires the availability of teaching aids, teaching staff and a technical training base. The experience of applying RTS in solving problems of automation of experimental research allows organizing the training of students in studying the principles of constructing and implementing components of the RTS.

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