Solaris 8操作系统实时能力的分析

随着实时应用变得越来越重要,人们希望能在Solaris等通用操作系统上开发和部署实时应用。对Solaris8操作系统的实时能力进行了分析,介绍了一个实时应用实例,提供了丰富的实时特性和良好的实时环境。     

嵌入式Linux操作系统的实时性能分析与改进

随着嵌入式应用越来越广泛，嵌入式操作系统受到极大的重视。传统的嵌入式实时操作系统，由于各种原因不能满足我国日益广泛的需求，快速开发一个价格低廉、效率较高的嵌入式实时操作系统迫切需要。利用现有的Linux操作系统进行改造，是其中很好的一个方法，然而Linux是一个通用的操作系统，在实时性能上还不能够满足需要，对Linux的实时性能进行了分析，并提出了改进Linux实时性能的方法。     

基于RTHAL的Linux实时性研究和实现

研究嵌入式Linux操作系统实时性的扩展和实现.提出通过在底层硬件和操作系统之间增加实时硬件抽象层的方式来扩充和增强Linux实时性能.该方法对操作系统内核只需做微小修改,就能达到既保持Linux现有功能和资源又兼有硬实时能力,其进程切换延迟仅为3微秒左右.讨论了对Linux和实时硬件抽象层两方面的扩展过程,同时还提出了如何有效利用两者间的缓冲区的方法.最后在嵌入式MPEG4流媒体系统中应用和测试了该方法,结果表明该方法实时性能优异,使用简单有效.     

基于RTAI的实时LINUX分析与实现

LINUX作为一种开放的操作系统已经得到广泛的应用,但是LINUX是面向桌面的操作系统,本身实时性并不是很出色,在很多应用场合需要对它的实时性能进行改进。本文详细分析了一种基于实时应用接口的LINUX扩展方案,通过RTAI动态加载实时内核,改善了LINUX系统的实时性。     

实时多任务航空通用测控系统数字仿真软件的研究与实现

介绍了在实时多任务多用户操作系统ＱＮＸ支持下，实时多任务航空通用测控系统数字仿真软件的设计目的、要求、组成和功能，重点讨论了实时多任务数字仿真软件的实现和解决的技术关键。     

基于RTX的卫星姿轨控系统地面实时仿真系统

介绍了RTX的实时功能原理和RT—TCPIP的实时通讯机制，并且比较了Windows操作系统和基于RTX实时扩展操作系统在实时精度方面和实时通讯方面的性能。卫星姿轨控系统地面仿真试验系统在卫星研制过程中起着举足轻重的作用。针对该系统的实时性要求，讨论了基于RTX的实时仿真系统的软件设计和实现方法，并给出了仿真实验结果。实验结果证明，该系统实时性高，工作稳定可靠，满足实际实验要求。该文对实时性要求高的仿真系统具有一定的参考价值和指导意义，     

基于RTAI/Linux的变电站微机监控装置实时性能研究

毫秒级的任务调度时延限制了标准Linux操作系统在电力系统微机监控装置中的应用。分析了操作系统自适应域环境Adeos（Adaptive Domain Environment for Operating System）的中断管道机制,利用实时应用接口RTAI（Real—Time Application Interface）对标准Linux操作系统进行实时扩展,并结合Cirrus Losic公司的基于EP9301处理器（ARM920T）的EDB9301工程开发板,设计了具有强实时性能的变电站微机监控装置。依据实时性将系统任务划分为实时任务部分和非实时任务部分,且实时任务和非实时任务通过管道（FIFOs）通信。测试数据显示,系统实时核上实时任务调度延迟在微秒级,可以满足硬实时的要求。     

通用访问控制框架扩展研究

通用访问控制框架（generalized framework for access control,GFAC)是经典的多安全政策支持结构，但是在实际实施多个安全政策模块之后暴露了它潜在的效率缺陷。通过引入访问决策缓冲器得到扩展的通用访问控制框架，并且在RS－Linux安全操作系统中完成实现，性能测算结果表明，扩展后的通用访问控制框架可以有效地弥补效率缺陷。     

基于Linux集群的分布式实时操作系统的设计

文章针对Linux集群环境,以Linux通用操作系统为基础,提出了一种分布式实时操作系统的设计思路。以分布式实时操作系统的特殊性为线索,详细阐述了分布式实时操作系统中实时任务调度机制、实时进程间通信机制和实时网络通信机制的设计思路。     

Linux 2.6内核进程调度分析

Linux操作系统是一种支持多任务、多用户和多处理器的现代通用操作系统。2．6内核的Linux支持0（1）级进程调度算法，支持可抢占内核，相比于2．4内核具有更好的实时性能。文中基于Linux2．6．10内核源代码，分析了Linux2．6内核的进程调度系统。并在详细介绍关键数据结构的基础上，阐述了进程调度算法的原理，并对实时进程的支持作了分析。     

Effects of dynamic isolation for full virtualized RTOS and GPOS guests

Industrial systems currently include not only control processing with real-time operating system (RTOS) but also information processing with general-purpose operating system (GPOS). Multicore-based virtualization is an attractive option to provide consolidated environment when GPOS and RTOS are put in service on a single hardware platform. Researches on this technology have predominantly focused on the schedulability of RTOS virtual machines (VMs) by completely dedicated physical-CPUs (pCPUs) but have rarely considered parallelism or the throughput of the GPOS. However, it is also important that the multicore-based hypervisor adaptively selects pCPU assignment policy to efficiently manage resources in modern industrial systems. In this paper, we report our study on the effects of dynamic isolation when two mixed criticality systems are working on one platform. Based on our investigation of mutual interferences between RTOS VMs and GPOS VMs, we found explicit effects of dynamic isolation by special events. While maintaining low RTOS VMs scheduling latency, a hypervisor should manage pCPUs assignment by event-driven and threshold-based strategies to improve the throughput of GPOS VMs. Furthermore, we deal with implicit negative effects of dynamic isolation caused by the synchronization inside a GPOS VM, then propose a process of urgent boosting with dynamic isolation. All our methods are implemented in a real hypervisor, KVM. In experimental evaluation with benchmarks and an automotive digital cluster application, we analyzed that proposed dynamic isolation guarantees soft real-time operations for RTOS tasks while improving the throughput of GPOS tasks on a virtualized multicore system.     

嵌入式实时操作系统μC/OS定时器服务的改进

实时操作系统对定时器精确度的要求大大高于通用操作系统,本文结合嵌入式实时操作系统μC/OS的具体特点,改进了它的时钟处理系统,包括细化时钟粒度、增加定时器服务。     

Extreme scale computing: Modeling the impact of system noise in multi-core clustered systems

System noise or Jitter is the activity of hardware, firmware, operating system, runtime system, and management software events. It is shown to disproportionately impact application performance in current generation large-scale clustered systems running general-purpose operating systems (GPOS). Jitter mitigation techniques such as co-scheduling jitter events across operating systems improve application performance but their effectiveness on future petascale systems is unknown. To understand if existing jitter mitigation solutions enable scalable petascale performance, we construct two complementary jitter models based on detailed analysis of system noise from the nodes of a large-scale system running a GPOS. We validate these two models using experimental data from a system consisting of 256 GPOS instances with 8192 CPUs. Based on our models, we project a minimum slowdown of 1.8%, 4.1%, and 6.5% for applications executing on a similar one petaflop system running 1024 GPOS instances and having global synchronization operations once every 100 ms, 10 ms, and 1 ms, respectively. Our projections indicate that–although existing mitigation solutions enable scalable petascale performance–additional techniques are required to contain the impact of jitter on multi-petaflop systems, especially for tightly synchronized applications.     

基于VxWorks的T比特路由器2.5GPOS接口板的设计与实现

因特网流量的快速增长,对骨干网的传输提出了更高的要求,为此我们研制了总吞吐率高达1.28T比特高性能IPv4/v6路由器。本路由器提供2.5GPOS,10GPOS,100M以太网,1000M以太网,10GLAN以太网,10GWAN以太网等接口,可方便组网。本文简要介绍了此路由器的总体结构,并深入研究了2.5GPOS接口板的设计与实现。     

Verification-Purpose Operating System for Microprocessor System-Level Functions

Microprocessor system-level functions that provide hardware support for software are difficult to verify on FPGA prototypes. Traditional FPGA verification involves running a general-purpose operating system such as Linux. However, such a GPOS is difficult to control, and debug is inefficient. The Verification-Purpose Operating System, on the other hand, simplifies debug and is easy to control. VPOS also significantly increases coverage over that of GPOS approaches.     

Windows实时扩展技术研究

Windows操作系统不能直接应用于实时领域。为此,从体系结构、基本系统策略、系统可靠性、实时应用程序开发难度和系统性能等方面,分析比较Windows实时扩展的2个典型产品——RTX和INtime。在此基础上,提出一种基于操作系统自适应域环境的Windows实时扩展方法。理论分析结果表明,该方法的灵活性、可靠性和可移植性优于目前常用方法。     

基于Jetty的网页防篡改技术的设计和实现

本文提出并实现了架设在符合J2EE标准的Web服务器上的网页防篡改系统,该系统主要采用Java语言开发和实现,能够对目前各种主流操作系统平台上的网页内容进行实时监控,发现网页被篡改时能及时恢复并报警,有效的保护目标网站的安全。     

TDCS: a new scheduling framework for real-time multimedia OS

ABSTRACT

The emerging real-time hyper-physical system (CPS), such as autonomous vehicle and live interactive media application, requires time deterministic behaviour. This is challenging to achieve by using the traditional general purpose operating system (GPOS). This paper presents a new design of the real-time operating system (OS) scheduling mechanism called ‘time deterministic cyclic scheduling’ (TDCS) mainly for live multimedia tasks processing. This new scheduler shares a similar philosophy as classic cyclic execution but with flexibility and dynamic configuration. This hybrid design is based on both time-reserved based cyclic execution and priority-based pre-emptive scheduling for mixed criticality applications. The simulation results show that this scheduling scheme can achieve predictable timing behaviour of task delay and jitter under high CPU utilisation. This shows that the proposed scheme is promising for low latency high-performance multimedia censoring tasks that occur in a periodic manner.     

Fault-Tolerant Rate-Monotonic Scheduling

Due to the critical nature of the tasks in hard real-time systems, it is essential that faults be tolerated. In this paper, we present a scheme which can be used to tolerate faults during the execution of preemptive real-time tasks. We describe a recovery scheme which can be used to re-execute tasks in the event of single and multiple transient faults and discuss conditions that must be met by any such recovery scheme. We then extend the original Rate Monotonic Scheduling (RMS) scheme and the exact characterization of RMS to provide tolerance for single and multiple transient faults. We derive schedulability bounds for sets of real-time tasks given the desired level of fault tolerance for each task or subset of tasks. Finally, we analyze and compare those bounds with existing bounds for non-fault-tolerant and other variations of RMS.     

实时嵌入式容错系统的关键技术研究

简要回顾了容错技术的发展过程并分析了不同故障模型下系统的客错方式.对于瞬时故障、间歇性故障的容错可采用软件冗余方法,在实时嵌入式系统中采用软件容错时必须考虑任务的可调度性;而永久性故障则采用硬件冗余方法来解决.在此基础上,描述了一种实时双机嵌入式容错系统的模型,研究了构建容错系统需要解决的双机同步、故障检测及仲裁切换等关键问题和相应的解决方法.