Constructing a Multi-OS Platform with Minimal Engineering Cost

This paper discuss on how to develop a hard real-time machine control system with Microsoft Windows NT Operating System, where the respond must be within 0.5 milliseconds. The attempt to use a general-purpose operating system (Microsoft Windows NT 4.0 Workstation) is because there is abundance of Commercial-Off-the-Shelf Components (COTS), easily available tools (compilers, and 3 party tools) and need not to learn another operating system behavior. The most important factor is there is no single dominant operating system or tools vendor for real-time operating system. Since the no single dominant real-time operating system development under real-time operating system is riskier and more costly. Ideally codes must be portable between different operating system where it is apparent with Windows platforms, Windows 95/98, Windows ME, Windows 2000, Windows XP or even Windows CE. Firstly study was done on how Microsoft Windows NT operating system works internally from materials from Microsoft Software Development Network (MSDN). Secondly study was done how to take advantage of the operating system to create a real time application. Microsoft Windows NT is a general purpose operating system that does not support real time application development, but it has all the vital elements that a real time operating system needs. The vital elements are priority-driven, preemptive scheduler, preemptive interrupt handler (for critical interrupts), deferred procedure calls (DPC) for non-critical (DPC executes after ISR), synchronization and deterministic response time. With these vital elements and some modification to application codes to enable it to execute in higher priority level, would result a real time application. This does not mean changing all the codes to higher priority is the solution, as it would cause system to malfunction as other device driver or low-level interface run at high priority too and this would lock up the system. With the combination of priority level, synchronization a complete real time solution can be implemented and this paper covers the concept. This concept also explains what was done to overcome the need of special hardware (as recommended) to accomplish hard real-time application with the response of 0.5 milliseconds.

The core idea in this project is to have two operating systems for both cores of dual core processor individually. General purpose operating system on one core and Real time operating system (RTOS) on second core. Implementation of same will be done by making one of core independent from General purpose operating system and install RTOS in that core so that both will work as one system i.e. General purpose operating system will look after the non-real time applications and RTOS will ensure that all real time application should not miss their deadline and executed as fast as they can. As by installing general purpose operating system and RTOS in both the cores of dual core processors of system and running them in parallel way, dual core processors is being used to its maximum efficiency. The advantage is that if one of OS gets crashed, whole system will not crash instead one of OS which didn't crash hold the system to safe mode till damaged OS is recovered.

This paper investigates the possibilities of using virtualization in multicore real-time embedded systems based on combination of general-purpose and real-time operating systems running on separate processor cores. The research is focused on ARM processor architecture due to its widespread usage in numerous application domains. The paper describes the concepts and practical considerations of using virtualization to achieve better interrupt latency both in Linux, as a typical representative of commonly used general-purpose operating system in applications requiring real-time response, and real-time operating system running on separate cores. In the proposed approach we demonstrate how to use virtualization mechanism to decouple cores responsible for real-time and non real-time tasks in a multiprocessor system with real-time requirements. Xen Hypervisor is used as a virtual machine monitor with default credit and new experimental null scheduler. The aim of research was to study the system response time characteristics and to assess practical usability of such approach in applications with hard real-time requirements.

The IGEM (Industrial Global Environment Manager), which is a real-time operating system with ITRON specifications, has been developed and applied to the mobile radio communication systems. This system is used for AVM (Automatic Vehicle Monitoring) and MCA systems (Multi Channel Access) which uses M68000 (MCP-16 board) CPUs, having several connections to more than one microcomputer. In this system, a general purpose operating system (OS-9)* and real-time operating system (IGEM) coexist,and they work together. This paper introduces examples of the use of this system and gives an evaluation of its operating system.

6 - Operating Systems

In the movie Matrix, our hero Neo must choose between taking the Blue Pill and continuing to live in an online, synthesized fantasy world, or taking the Red Pill and joining the real world. The fantasy world appears to those living in it to be full of flowers and trees and big steak dinners, but unknown to them contains malicious Agents who can alter any portion of the world to suit their needs. The real world, in turn, while real, has no visible sun, and the people have only gray mush for food.Authorization and authentication of online transactions across a network requires a trusted path between the user and the server. We posit that those who attempt to solve this problem by creating the trusted path on the general-purpose operating system have taken the Blue Pill and are living in a fantasy world. One simply cannot properly secure a general-purpose operating system.Solving the problem by taking the Red Pill and completely replacing currently used operating systems with ones that we can properly secure does not seem palatable. We suggest a solution that involves taking both the Blue Pill and the Red Pill: providing the trusted path by means of a separate device with a secure operating system, used in tandem with the existing general purpose operating system. Most user interaction occurs on the un-trusted system, with the secure device only being used to finalise transactions.We believe that the technology required for such a device is readily available. Obviously our idea is not a completely novel idea; prior work in the area has had a similar goal. However, most of those attempts have not properly addressed the requirements for the trusted system, generally preferring to use existing general-purpose systems even when on a dedicated [Balfanz 1999] [Kingpin 2001] Others have a very limited scope of use. [Blakely 2004].We identify a minimum set of requirements for the trusted device. This paper does not provide a working solution (it is a position paper after all); we simply define how one should approach that working solution. Because we advocate a hybrid system it is possible to simplify the trusted system to a point where it would not be usable as a general purpose system, which should make the trusted system rather easier to build and have confidence in.

The picky needs raised in the embedded market lead to the growth of real-time operating systems (RTOS), which differ from the general-purpose operating systems (GPOS) by applying strict timing and providing predictable execution of tasks. Some features of a real-time application, such as human interaction and some data transfers to other components are not time-critical. As the general-purpose operating system requires access to the data gathered by the real-time operating system, these two should be consolidated on the same platform form a hybrid system. This proposal examines how the existing Sloth approach of interrupt-driven scheduling can apply to a hybrid system running both a real-time and the Linux kernel simultaneously on the unchanged hardware. This entails a make another study of existing approaches towards a real-time capable Linux and the design of a communication channel between the real-time core and processes running in Linux kernel. The evaluation of the resulting Slothful Linux is supposed to show the advantages of the Sloth approach in a hybrid system compared to both the standalone Sloth and another real-time conservatory for Linux.

Network Function Virtualization (NFV) has recently gained popularity due to its ability of offering high scalability and programmability using commodity servers and general-purpose operating system (OS). However, current OSes have failed to deliver the data-plane performance required by the software-based network functions, mainly due to the inherent overheads associated with network stack in the kernel. We present mKPAC, aimed at improving data plane performance of OS kernel in manycore environment. We analyze the high-impact overheads residing in network stack of Linux kernel, and show that the data plane performance for NFV can be accelerated by mitigating major performance penalties and by leveraging the availability of manycores. With 64 bytes packet size, mKPAC can successfully accelerate the Linux Kernel packet forwarding performance up to 40% in packets per second.

We investigate operating system noise, which we identify as one of the main reasons for a lack of synchronicity in parallel applications. Using a microbenchmark, we measure the noise on several contemporary platforms and find that, even with a general-purpose operating system, noise can be limited if certain precautions are taken. We then inject artificially generated noise into a massively parallel system and measure its influence on the performance of collective operations. Our experiments indicate that on extreme-scale platforms, the performance is correlated with the largest interruption to the application, even if the probability of such an interruption is extremely small. We demonstrate that synchronizing the noise can significantly reduce its negative influence

This paper explores the intersection of operating systems and database systems, focusing on the potential of specialized kernels for cloud-native database systems. Although the idea of custom, DBMS-optimized OS kernels is old, it is largely unrealized due to the demands of hardware compatibility and the reluctance of users to install specialized operating systems. However, the cloud and the database-as-a-service model make custom OS kernels realistic for the first time. Among specialized OS kernel architectures, unikernels stand out for relying on a single address space, eliminating the need for costly process isolation that is provided by general-purpose operating systems. They offer benefits such as the elimination of system call overhead, direct access to hardware, and reduced complexity. Beyond these immediate advantages, unikernels offer a unique opportunity: the possibility to revisit dated POSIX APIs. By allowing direct interaction with modern hardware primitives, unikernels pave the way for the development of novel abstractions that are not confined to the limitations of older APIs, opening doors to a new era of co-designed, high-performance cloud-native data processing systems and OS kernels.

In this paper, we propose a method implementing real-time scheduling in the Unix, a general-purpose operating system (GPOS), by considering the deadline of real-time tasks. Our approach employs a special task called the scheduling daemon, which deals with all the real-time tasks in a system and makes just one task become a ready-to-run state and other sleep states. This causes the Unix scheduler to deal with only one real-time task as a rule, and thus bypasses time sharing-based scheduling strategy of the Unix. Therefore, all the real-time tasks are scheduled by the strategy of the scheduling daemon. We implement the scheduling daemon on the Unix, and build a real-time platform in order that application programmers develop real-time systems more effectively. Moreover, we show the superiority of our approach through extensive experiments.

In recent years, the number of invested resources adopted in experiments of embedded applications dropped significantly as many simulation technologies are widely used. However, the efficiency of simulations is seriously influenced by some expensive and difficult-to-obtain devices. It is urgent and of great significance to build a universal simulation platform for embedded applications on general-purpose operating systems with an objective of improving the efficiency and effectiveness of system development and implementation. Since virtualization technology can greatly enhance the simulation efficiency by providing virtual models to simulate the behaviors of real devices, this paper designs and realizes a real-time simulation platform on general-purpose operating systems with the virtualization technology such that embedded applications would be correctly and efficiently debugged and tested on the general-purpose operating systems. The proposed simulation platform contains four layers named hardware resource, virtualization, virtual runtime environment, and interface adaptation, allowing dynamic debugging and testing of embedded applications without requiring the actual presence of real devices. Experiments are conducted to verify the functionalities of the proposed simulation platform, and results demonstrate that the proposed simulation platform can meet the real-time and high reliability requirements of embedded applications.

<div class="htmlview paragraph">The new generation of drive-by-wire systems currently under development has demanding requirements on the electronic architecture. Functions such as brake-by-wire or steer-by-wire require continued operation even in the presence of component failures. The electronic architecture must therefore provide fault-tolerance and real-time response. This in turn requires the operating system and the communication layer to be predictable, dependable and composable. It is well known that this properties are best supported by a time-triggered approach. A consortium consisting of German and French car manufacturers and suppliers, which aims at becoming a working group within the OSEK/VDX initiative, the OSEKtime consortium, is currently defining a specification for a time-triggered operating system and a fault-tolerant communication layer.<span class="xref"><sup>1</sup></span> The operating system and the communication layer are based on applicable interfaces of the OSEK/VDX standard. This paper describes the basic concepts of these two service layers and the electronic architecture.</div>

Control systems for industrial processes are more and more using PC-based platforms instead of dedicated devices such as controllers or PLCs. Software packages allow running a "soft PLC" on a normal PC with a general purpose operating system. These solutions present several advantages in terms of flexibility, communications, multi-vendor interfacing, and costs. On the other hand the use of multi-tasking operating systems does not guarantee a-priori respect of the time constrains that control applications present. The paper describes a procedure for measuring the time performances of a soft-PLC with different configurations and loading. Results of preliminary measures are presented and discussed.

We propose and analyze a proportional share resource allocation algorithm for realizing real-time performance in time-shared operating systems. Processes are assigned a weight which determines a share (percentage) of the resource they are to receive. The resource is then allocated in discrete-sized time quanta in such a manner that each process makes progress at a precise, uniform rate. Proportional share allocation algorithms are of interest because: they provide a natural means of seamlessly integrating real and non-real-time processing; they are easy to implement; they provide a simple and effective means of precisely controlling the real-time performance of a process; and they provide a natural means of policing so that processes that use more of a resource than they request have no ill-effect on well-behaved processes. We analyze our algorithm in the context of an idealized system in which a resource is assumed to be granted in arbitrarily small intervals of time and show that our algorithm guarantees that the difference between the service time that a process should receive and the service time it actually receives is optimally bounded by the size of a time quantum. In addition, the algorithm provides support for dynamic operations, such as processes joining or leaving the competition, and for both fractional and non-uniform time quanta. As a proof of concept we have implemented a prototype of a CPU scheduler under FreeBSD. The experimental results shows that our implementation performs within the theoretical bounds and hence supports real-time execution in a general purpose operating system.