服务体模型与操作系统内核设计技术

操作系统内核通常分为宏内核和微内核两类,前者可扩展性与可维护性很差,而后者效率低下,缺乏实用性服务体模型是一种新型的操作系统构造模型,该模型使其存储抽象与运行抽象相分离,并采用一种新的基于消息推动的通信机制,既保持了微内核模型灵活和可扩展性,又具有很高的运行效率．MiniCore是基于服务体模型的一个原型操作系统,通过将该操作系统应用于路由器硬件实验平台,以实例说明了所提出操作系统构造模型的优越性．     

多态操作系统

本文简要介绍了传统的单态和两态结构操作系统，分析了微内核结构操作系统中采用两态结构仿真传统操作系统ＡＰＩ界面的不足。最后介绍了多态操作系统的思想及其在国产操作系统ＣＯＳＩＸＶ２．０中的实现     

客户／服务器环境下的OS／22·1操作系统

ＯＳ／２２·１是当今客户／服务器计算模式的首选操作系统之一。本文对ＩＢＭＯＳ／２２·１操作系统所具备的，对客户／服务器计算模式的各种支持功能作了详细的介绍。     

Enhancing a dependable multiserver operating system with temporal protection via resource reservations

Nowadays, microkernel-based systems are getting studied and adopted with a renewed interest in a wide number of IT scenarios. Their advantages over classical monolithic solutions mainly concern the dependability domain. By being capable of dynamically detect and solve non-expected behaviours within its core components, a microkernel-based OS would eventually run forever with no need to be restarted. Dependability in this context mainly aims at isolating components from a spatial point of view: a microkernel-based system may definitely not be adopted in the context of real-time environments, simply basing on this kind of protection only. One of the most active real-time research areas concerns adding temporal protection mechanisms to general purpose operating systems. By making use of such mechanisms, these systems become suitable for being adopted in the context of time-sensitive domains. Microkernel-based systems have always been thought of as a kind of platform not suited to real-time contexts, due to the high latencies introduced by the message passing technique as the only inter-process communication (IPC) facility within the system. With computer performances growing at a fairly high rate, this overhead becomes negligible with respect to the typical real-time processing times. In the last years, many algorithms belonging to the class of the so-called Resource Reservations (RRES) have been devised in order to provide the systems with the needed temporal isolation. By introducing a RRES-aware scheduler in the context of a microkernel-based system, we may enrich it with the temporal benefits it needs in order to be deployed within domains with real-time requirements. In this paper we propose a generic way to implement these mechanisms, dependent for a very small part on the underlying OS mechanisms. In order to show the generality of our RRES framework we implemented it in the context of Minix 3, a highly dependable microkernel-based OS with an impressive users base.     

基于Agent微内核工作流技术研究

工作流引擎作为基于工作流的信息系统的核心技术,发挥了越来越重要的作用,可能成为信息系统基础性的通用框架平台。借鉴操作系统的微内核思想,将其引入到工作流系统设计中,建立起基于微内核的层次分明的工作流系统。为了能在异步的分布式环境中进行部署和通信,在微内核的设计中采用Agent机制。以WMFC标准参考模型为基本要素,将微内核思想、Agent技术融合起来,构建一个基于Agent微内核工作流系统。     

Apple's Leopard Versus Microsoft's Windows XP: Experimental Evaluation of Apple's Leopard Operating System with Windows XP-SP2 under Distributed Denial of Service Security Attacks

ABSTRACT

Apple's iMac computers are promoted by Apple Inc. to be secure, safe, virus free, and fast computers. In this experimental paper, we evaluate the security offered by the iMac with its usual Leopard Operating System, against different Distributed Denial of Service (DDoS) attacks in a Gigabit LAN environment. We compared the effect of DDoS attacks on Leopard OS against those on the Window's XP-SP2 when installed on the same iMac platform under the same network attack environment. DDoS-based flooding attacks can originate in a LAN environment or can be from the Internet, which can have an impact on a victim computer with a barrage of Denial of Service (DoS) packet requests, thereby exhausting the resources of the victim computer in processing these requests. To study the impact on iMac computers, we created the corresponding DDoS traffic in a controlled lab environment to test against iMac computer that first deployed Leopard OS. Later, the same iMac platform was made to use Window's XP OS. We compared the behavior of Apple's Leopard OS with Windows's XP-SP2 OS under Ping Flood, ICMP Land, TCP-SYN, Smurf Flood, ARP Flood, and UDP Flood attacks. It was found that the Apple's iMac computer using its usual Leopard operating system crashed even under low bandwidth of ARP-based attack traffic, requiring forced reboot of the iMac computer. Interestingly, when compared with Microsoft's Windows XP-SP2 operating system, deployed on the same iMac platform, the computer was able to sustain the attack and did not crash. Our discovery of this vulnerability shows that Apple's popular operating systems, namely Leopards, commonly deployed on iMacs are prone to crash under ARP-based security attacks. Also in other attacks Windows XP-SP2 was found to have a better performance than Leopard in terms of resource consumption.     

Comlnk—a file transport and job entry utility for a communication link

COMLNK is a software system designed to provide the user of a communication link between two processors with facilities for file transport and Job submission from one computer to another. It has been implemented for a high speed communication link between an IBM 360/370 running under OS/MFT, MVT VS1 or VS2 and a PDP 11 running under DOS. The various record formats which are supported by the operating systems for their file organizations can be handled in a straightforward manner, while conversion options from one format to another are possible. Files may be shipped, listed on the IBM printer, punched on the IBM punch or submitted to the jobqueue.     

一个教学用操作系统的设计与实现

本文首先指出了现有的教学用操作系统存在的不足,然后设计并实现了一个运行在虚拟机上的微内核结构的教学用操作系统,描述了系统中进程管理、进程间通信、基本内存管理、磁盘服务器以及文件服务器的设计和实现。本系统的实现将有利于学生从微观上观察操作系统的行为特征,并且帮助他们理论联系实际,具有较好的教学价值。     

操作系统微内核技术研究*

文章介绍了作者在过去5年中在微内核技术上所做的工作.给出了3个算法.① 通过将任务调度和线程调度算法相结合的方法，来解决单纯以线程为单位的调度系统的效率和公平性问题；② 一个改进的写时拷贝算法，它结合写时拷贝算法和访问时拷贝算法的优点，来解决写时拷贝算法在I386体系结构上的适应性问题；③ 提出了一个微内核操作系统计时模型，它解决了传统计时算法在微内核系统中计时不准确的问题.     

Securing the OS/2 Operating Environment

IBM developed the OS/2 operating system in response to several changes in the microcomputing environment. Users demanded the ability to use more sophisticated programs on microcomputers; these programs required more memory and power than was available on DOS-based computers. Users also wanted a friendlier interface to the operating system, the ability to perform more than one task at a time, and the ability to connect and share processing with other computers. DOS-based systems were limited in all of these respects. For example, although DOS systems could be made to function as a node on a LAN (with the addition of a LAN card), they were still unable to share processing with other computers on the network.     

微核心操作系统的结构对性能的影响

微核心操作系统是近些年出现的。它已成为操作系统的发展方向和趋势。微核心操作系统本身具有许多优点,但目前的一些微核心操作系统存在一个严重问题,即性能不佳。导致微核心操作系统性能不佳的主要原因是在实现微核心思想时所采用的系统结构和实现技术不尽合理。文中分析了在微核心操作系统的结构方面存在着哪些影响系统性能的因素,以及它们是如何影响系统性能的。这些因素是在微核心技术的研究工作中应该认真考虑的问题。     

A software trace facility for OS/MVT

This paper describes a software trace facility (STF) developed to provide data about the flow of control between modules of the IBM System/360 operating system OS/MVT. The motivation for STF is discussed and a brief Introduction to OS/MVT presented to show how STF interfaces with the operating system. The output of the program is illustrated and some details of the program logic are discussed together with the tracing options available to the user. The paper then describes some potential applications.     

微内核中断机制的形式化设计与验证

操作系统的正确性和安全性很难用定量的方法进行描述。形式化方法是操作系统设计和验证领域公认的标 准方法。以操作系统对象语义模型(OSOSM)为基础,采用形式化方法对微内核架构的中断机制进行了设计和验证, 在自行开发的安全可信操作系统VTOS上加以实现,采用Isabelle/HOL对设计过程进行了形式化描述,对VTOS中 断机制的完整性进行了验证,这对操作系统的形式化设计和验证工作起到了一定的借鉴意义。     

Deep learning MRI signature to predict survival and treatment benefit from temozolomide in IDH-wildtype glioblastoma

BackgroundO⁶-methylguanine-DNA-methyltransferase (MGMT) methylation status does not correlate with temozolomide (TMZ) sensitivity in all IDH-wildtype glioblastoma (GBM) patients. New predictors of TMZ benefit are still in demand.MethodsBased on MR images, a deep learning image signature was constructed to predict the survival and benefit of temozolomide in patients with IDH wild-type glioblastoma.ResultsDiS signature was associated with OS as an independent prognostic factor in patients with IDH-wildtype glioblastoma. For high-risk group patients, TMZ was associated with improved OS for patients in MGMT-methylated subgroup (HR: 2.051, 95 % CI: 0.939–4.482, log-rank P = 0.034), but had not effect on MGMT-unmethylated patients. However, patients in the low- risk group did not benefit from TMZ.ConclusionDiS could offer complementary value beyond MGMT methylation status in predicting survival benefit from TMZ chemotherapy in patients with IDH-wildtype glioblastoma.     

Using both virtual 8086 and protected modes to implement OBJIX microkernel on 180386

This paper presents the techniques used in a microkernel based on I80386/80486 architecture. These techniques were created during the OBJIX project—an object-oriented operating system design. One of the goals of the system was to combine the virtual 8086 and the protected mode of the processor. To achieve the goal, new concepts such as stand-in process, exception stand-in process and superkernel are introduced. At the end of the paper, a proof is given that no consistent hardware support for preemptive context switching on I80386 exists if the context switching is mediated by a timer process.     

User-level Real-Time Network System on Microkernel-based Operating Systems

This paper presents the design and implementation of a user-level real-time network system in Real-Time Mach. Traditional network systems for microkernel based operating systems, which tend to focus on high performance and flexibility, are not suitable for real-time communication. Our network system provides a framework for implementing real-time network protocols which require to bound protocol processing time, and it is suitable for implementing on microkernel based operating systems. In this paper, we especially focus on the aspects to avoid the priority inversion problem in order to make network systems more preemptable and predictable. We also describe the feasibility of our network system for building distributed multimedia systems.     

MultiSpec—a tool for multispectral–hyperspectral image data analysis

MultiSpec is a multispectral image data analysis software application. It is intended to provide a fast, easy-to-use means for analysis of multispectral image data, such as that from the Landsat, SPOT, MODIS or IKONOS series of Earth observational satellites, hyperspectral data such as that from the Airborne Visible–Infrared Imaging Spectrometer (AVIRIS) and EO-1 Hyperion satellite system or the data that will be produced by the next generation of Earth observational sensors. The primary purpose for the system was to make new, otherwise complex analysis tools available to the general Earth science community. It has also found use in displaying and analyzing many other types of non-space related digital imagery, such as medical image data and in K-12 and university level educational activities.MultiSpec has been implemented for both the Apple Macintosh^® and Microsoft Windows^® operating systems (OS). The effort was first begun on the Macintosh OS in 1988. The GLOBE (http://www.globe.gov) program supported the development of a subset of MultiSpec for the Windows OS in 1995. Since then most (but not all) of the features in the Macintosh OS version have been ported to the Windows OS version.Although copyrighted, MultiSpec with its documentation is distributed without charge. The Macintosh and Windows versions and documentation on its use are available from the World Wide Web at URL:http://dynamo.ecn.purdue.edu/biehl/MultiSpec/MultiSpec is copyrighted (1991–2001) by Purdue Research Foundation, West Lafayette, Indiana 47907.     

EMERALDS: a small-memory real-time microkernel

EMERALDS (Extensible Microkernel for Embedded, ReAL-time, Distributed Systems) is a real-time microkernel designed for small-memory embedded applications. These applications must run on slow (15-25 MHz) processors with just 32-128 kbytes of memory, either to keep production costs down in mass produced systems or to keep weight and power consumption low. To be feasible for such applications, the OS must not only be small in size (less than 20 kbytes), but also have low overhead kernel services. Unlike commercial embedded OSs which rely on carefully optimized code to achieve efficiency, EMERALDS takes the approach of redesigning the basic OS services of task scheduling, synchronization, communication, and system call mechanism by using characteristics found in small-memory embedded systems, such as small code size and a priori knowledge of task execution and communication patterns. With these new schemes, the overheads of various OS services are reduced 20-40 percent without compromising any OS functionality     

File Input/Output Control Logic

This paper focuses on a key issue in operating system design that has hitherto received no explicit attention in the literature–file input/output control logic. Particular attention is concentrated on two well-known systems: the IBM System/360 under OS, and the Burroughs 1700 under the Master Control Program.     

操作系统体系结构研究

1 引言操作系统作为计算机系统中最重要的一种系统软件,负责管理计算机系统资源,为用户使用计算机提供了方便、快捷的手段。目前还没有有关操作系统的精确的定义。在谈到操作系统时,人们总是用用户环境观点、或虚拟机观点、或资源管理观点,从不同的侧面来说明操作系统的基本特征。操作系统的理论和实践也是围绕着这些观点进行的。