OPERATING SYSTEM

In 2005, Oak Ridge National Laboratory received delivery of a 5,294 processor Cray XT3. The XT3 is Cray's third-generation massively parallel processing system. The ORNL system uses a singleprocessor node built around the AMD Opteron and uses a custom chip-called SeaStar-for interprocessor communication. The system uses a lightweight operating system called Catamount on its compute nodes. This paper provides a performance evaluation of the Cray XT3, including measurements for microbenchmark, kernel, and application benchmarks. In particular, we provide performance results for strategic Department of Energy applications areas including climate, biology, astrophysics, combustion, and fusion. Our results, on up to 4,096 processors, demonstrate that the Cray XT3 provides competitive processor performance, high interconnect bandwidth, and high parallel efficiency on a diverse application workload, typical in the DOE Office of Science.

In this work an optimized version of the field-mill sensor structure for atmospheric electric field measurements was presented. Both the mechanical structure and the electronic front-end, acquisition and control system are optimized in order to reduce the power consumption and to enhance the instrument metrological performance in term of sensitivity and frequency band. A solar power operated system was realized and tested. The developed system is also equipped with a GPS receiver, allowing data synchronization. This feature enables the implementation of a distributed measurement system for the monitoring of the atmospheric electric field.

The integration of strong encryption into operating systems is creating challenges for forensic examiners, potentially preventing us from recovering any digital evidence from a computer. Because strong encryption cannot be circumvented without a key or passphrase, forensic examiners may not be able to access data after a computer is shut down, and must decide whether to perform a live forensic acquisition. In addition, with encryption becoming integrated into the operating system, in some cases, virtualization is the most effective approach to performing a forensic examination of a system with FDE. This paper presents the evolution of full disk encryption (FDE) and its impact on digital forensics. Furthermore, by demonstrating how full disk encryption has been dealt with in past investigations, this paper provides forensics examiners with practical techniques for recovering evidence that would otherwise be inaccessible.

In recent times, globalization has brought us not only new opportunities but also new challenges. The theme of innovation has become a mandatory topic for all industries—it has become a focal point for the enterprise, society, and the world. The goal of innovation is to create business value by developing worthwhile ideas into a customer-centric marketable reality. This, for most

This paper presents the development of a unique parallel and distributed real-time digital simulator for power engineering research at the University of Alberta. The simulator is built entirely from commodity-off-the-shelf (COTS) hardware and software components, making it very flexible and scalable. In parallel multi-tasking operations, a combination of real-time Linux operating system and an ultra-fast network forms the backbone for the internal communication between the 16 powerful processors of the Xeon-Cluster. Field programmable gate array (FPGA)-based multi-channel digital and analog I/O ports are interfaced to communicate with the external hardware components. The model development software utilized for power applications is based on the highly customizable industry-standard MATLAB/SIMULINK environment. A detailed case study of the real-time simulation of a three-level 12-pulse vector-controlled ac drive is presented to illustrate the precision capabilities of the simulator. Multiple integration algorithms and multirate computation have been applied for the simulation of the system, with slow (machine) and fast (converter) dynamic components. Real-time simulation of the entire system has been achieved with a maximum computation time of 5.35 s on a step-size of 10 s for the first time. Results obtained from the real-time simulation have been validated with an offline simulation using PSCAD/EMTDC. Index Terms-Field programmable gate arrays (FPGA), parallel processing, power engineering, real-time systems.

We present DROIDCAP, a retrofitting of Android's central Binder IPC mechanism to change the way how permissions are being represented and managed in the system. In DROIDCAP, permissions are per-process Binder objectcapabilities. DROIDCAP's design removes Android's UID-based ambient authority and allows the delegation of capabilities between processes to create least-privileged protection domains efficiently. With DROIDCAP, we show that object-capabilities as underlying access control model integrates naturally and backward-compatible into Android's stock permission model and application management. Thus, our Binder capabilities provide app developers with a new path to gradually adopting app compartmentalization, which we showcase at two favorite examples from the literature, privilege separated advertisement libraries and least privileged app components. At the heart of our paradigm shift for representing permissions in Android is an extension to Android's Binder IPC mechanism. Binder IPC is the primary IPC channel for communication among all apps and between system services

Cloud computing is basically altering the expectation for how and when computing, storage and networking assets should be allocated, managed and devoted. End-users are progressively more sensitive in response time of services they ingest. Service Developers wish for the Service Providers to make sure or give the ability for dynamically assigning and managing resources in respond to alter the demand patterns in real-time. Ultimately, Service Providers are under anxiety to build their infrastructure to facilitate real-time end-to-end visibility and energetic resource management with well grained control to decrease total cost of tenure for improving quickness. What is required to rethink of the underlying operating system and management infrastructure to put up the ongoing renovation of data centre from the traditional server-centric architecture model to a cloud or network centric model? This paper projects and describes a indication model for a network centric data centre infrastructure management heap that make use of it and validates key ideas that have enabled dynamism, the quality of being scalable, reliability and security in the telecommunication industry to the computing engineering. Finally, the paper will explain a proof of concept classification that was implemented to show how dynamic resource management can be enforced to enable real-time service guarantee for network centric data centre architecture.

Reuters Corpus Volume I (RCV1) is an archive of over 800,000 manually categorized newswire stories recently made available by Reuters, Ltd. for research purposes. Use of this data for research on text categorization requires a detailed understanding of the real world constraints under which the data was produced. Drawing on interviews with Reuters personnel and access to Reuters documentation, we describe the coding policy and quality control procedures used in producing the RCV1 data, the intended semantics of the hierarchical category taxonomies, and the corrections necessary to remove errorful data. We refer to the original data as RCV1-v1, and the corrected data as RCV1-v2. We benchmark several widely used supervised learning methods on RCV1-v2, illustrating the collection's properties, suggesting new directions for research, and providing baseline results for future studies. We make available detailed, per-category experimental results, as well as corrected versions of the category assignments and taxonomy structures, via online appendices.

Korea Astronomy and Space Science Institute (KASI) launched the development project of two satellite laser ranging (SLR) systems in early 2008 after the government fund approval of the SLR systems in 2007. One mobile SLR system and one permanent SLR station will be developed with the completion of the project. The main objectives of these systems will be focused on the Space Geodetic researches. A system requirement review was held in the second half of the same year. Through the following system design review meeting and other design reviews, many unsolved technical and engineering issues would be discussed and resolved. However, the design of the mobile SLR system is a corner stone of whole project. The noticeable characteristics of Korea's first SLR system are 1) use of light weight main mirror, 2) design of compact optical assembly, 3) use of KHz laser pulse, 4) use of commercial laser generator, 5) remote operation capability, 6) automatic tracking, 7) state of art operation system, etc. In this paper, the major user requirement and pre-defined specification are presented and discussed.

Malware is one of the major security threats that can break computer operation. However, commercial antivirus or anti-spyware that used signature-based matching to detects malware cannot solve that kind of threats. Nowadays malware writers try to avoid detection by using several techniques such as polymorphic, metamorphic and also hiding technique. In order to overcome that issue, we proposed a new framework for malware behavior identification and classification that apply dynamic approach. This framework consists of two major processes such as behavior identification and malware classification. These two major processes will integrate together as interrelated process in our proposed framework. Result from this study is a new framework that able to identify and classify malware based on it behaviors.

Web server performance has steadily improved since the inception of the World Wide Web. We observe performance gains of two orders of magnitude between the original process-based Web servers and today’s threaded Web servers. Commercial and academic Web servers achieved much of these gains using new or improved event-notification mechanisms and techniques to eliminate reading and copying data, both of which required new operating system primitives. More recently, experimental and production Web servers began integrating HTTP processing in the TCP/IP stack and providing zero copy access to a kernel-managed cache. These kernelmode Web servers improved upon newer user-mode Web servers by a factor of two to six. This paper analyzes the significant performance gap between the newer user-mode and kernel-mode Web servers on Linux and Windows 2000. Several user-mode and kernel-mode Web servers are compared in three areas: data movement, event notification, and communication code path. To est...

Recent advances in the development of reconfigurable optical interconnect technologies allow for the fabrication of low cost and run-time adaptable interconnects in large distributed shared-memory (DSM) multiprocessor machines. This can allow the use of adaptable interconnection networks that alleviate the huge bottleneck present due to the gap between the processing speed and the memory access time over the network. In this paper we have studied the scheduling of tasks by the kernel of the operating system (OS) and its influence on communication between the processing nodes of the system, focusing on the traffic generated just after a context switch. We aim to use these results as a basis to propose a potential reconfiguration of the network that could provide a significant speedup.

Linux has become one of the most popular UNIX operating systems. Commercial support for Linux and adoption of Linux in real world applications have n o w started to emerge. Some of the applications have strict real-time requirements. In this paper, we discuss how to make Linux a real-time operating system. The realtime capability i s a c hieved by three new kernel mechanisms. We port a microtimer into the kernel. We adopt the time-driven scheduling paradigm and implement a time-driven scheduler in the Linux kernel. Finally, we insert preemption points in the kernel to make it more preemptable so that real-time jobs may experience shorter blockings. Our approach is general and may be used to enhance the real-time capability of other non-real-time operating systems as well.

Many emerging Web services, such as email, photo sharing, and web site archives, need to preserve large amounts of quickly-accessible data indefinitely into the future. In this paper, we make the case that these applications' demands on large scale storage systems over long time horizons require us to re-evaluate traditional storage system designs. We examine threats to long-lived data from an end-to-end perspective, taking into account not just hardware and software faults but also faults due to humans and organizations. We present a simple model of long-term storage failures that helps us reason about the various strategies for addressing these threats in a cost-effective manner. Using this model we show that the most important strategies for increasing the reliability of long-term storage are detecting latent faults quickly, automating fault repair to make it faster and cheaper, and increasing the independence of data replicas.

In the view of escalating global threat in security, it is imperative to have an automated detection system that can pick up suspicious patterns of human movement in physical environments. It can give a forewarning before a planned attack happens or an ultimate security is breached. In the past, significant research on the Intrusion Detection was established, but limited to virtual environments like computer networks and operating systems. In this paper, we proposed a general security model for detecting suspicious patterns in physical environment. Suspicious patterns are subtle and we showed that they can be detected via an experiment.

Most hypervisors today rely either on (1) full virtualization on high-end hardware (i.e., hardware with virtualization extensions), (2) paravirtualization, or (3) both. These, however, do not fulfill embedded systems' requirements, or require legacy software to be modified. Full virtualization on low-end hardware (i.e., hardware without virtualization extensions), on the other end, has none of those disadvantages. However, it is often claimed that it is not feasible due to an unacceptably high virtualization overhead. We were, nevertheless, unable to find real-world quantitative results supporting those claims. In this paper, performance and footprint measurements from a case study on low-end hardware full virtualization for embedded applications are presented. More specifically, this paper presents: (1) an evaluation of the virtualization overhead in a Linuxbased system as a guest on POK/rodosvisor, a real time operating system for embedded systems featuring low-end hardware full virtualization; (2) a detailed look at the performance of POK/rodosvisor's internal operation, namely, interrupt handlers and context switching; and (3) POK/rodosvisor's footprint for various configurations. To the best of our knowledge, this is the first paper ever to present performance measurements about a Linux-based system as a guest on a hypervisor based on low-end hardware full virtualization, and therefore, targeting a common real-world scenario.

Mobile objects have gained a lot of attention in research and industry in the recent past, but they also have a long history. Security is one of the key requirements of mobile objects, and one of the most researched characteristics related to mobility. Resource management has been somewhat neglected in the past, but it is being increasingly addressed, in both the context of security and QoS. In this paper we place a few systems supporting mobile objects in perspective based upon how they address security and resource management. We start with the theoretical model of Actors that supports concurrent mobile objects in a programming environment. Then we describe task migration for the Mach microkernel, a case of mobile objects supported by an operating system. Using the OMG MASIF standard as an example, we then analyze middleware support for mobile objects. Mobile Objects and Agents (MOA) system, is an example of middleware level support based on Java. The active networks project, Conv...

The goal of the GUARDS project is to design and develop a generic fault-tolerant computer architecture that can be built from predefined standardised components. The architecture favours the use of commercial off-the-shelf (COTS) hardware and software components. However, the assessment and selection of COTS components is a non-trivial task as it requires balancing a myriad of requirements from end-users and the preliminary architecture design. In this paper, we present the requirements and assessment criteria for a specific COTS software component, the operating system kernel. As an interface specification constitutes a major compatibility criterion for the selection of COTS components in GUARDS, a particular emphasis is placed on operating system conformance to the POSIX 1003.1 standard. We discuss the general lessons learned from the assessment process and raise a number of questions relevant to the assessment of any COTS software component.

We describe the design and implementation of Dynamo, a software dynamic optimization system that is capable of transparently improving the performance of a native instruction stream as it executes on the processor. The input native instruction stream to Dynamo can be dynamically generated (by a JIT for example), or it can come from the execution of a statically compiled native binary. This paper evaluates the Dynamo system in the latter, more challenging situation, in order to emphasize the limits, rather than the potential, of the system. Our experiments demonstrate that even statically optimized native binaries can be accelerated Dynamo, and often by a significant degree. For example, the average performance of -O optimized SpecInt95 benchmark binaries created by the HP product C compiler is improved to a level comparable to their -O4 optimized version running without Dynamo. Dynamo achieves this by focusing its efforts on optimization opportunities that tend to manifest only at runtime, and hence opportunities that might be difficult for a static compiler to exploit. Dynamo's operation is transparent in the sense that it does not depend on any user annotations or binary instrumentation, and does not require multiple runs, or any special compiler, operating system or hardware support. The Dynamo prototype presented here is a realistic implementation running on an HP PA-8000 workstation under the HPUX 10.20 operating system.

MEDICUS is a teleradiology system which has been developed in a joint project of the German Cancer Research Center (Deutsches Krebsforschungszentrum) and the Transfer Center Medical Informatics (Steinbeis-Transferzentrum Medizinische Informatik) in Heidelberg, Germany. The system is designed to work on ISDN lines as well as in a local area network. Special attention has been given to the design of the user interface and data security, integrity, and authentication. The software is in use in 13 radiology departments in university clinics, small hospitals, private practices, and research institutes. More than 25 thousand images have been processed in 6 months. The system is in use in six different application scenarios. MEDICUS is running under the UNIX operating system. The connection of the modalities could in most cases not be realized with the DICOM protocol as older machines were not equipped with this standard protocol. Clinical experiences show that the MEDICUS system provides a very high degree of functionality. The system has an efficient and user friendly graphical user interface. The result of a comparison with other systems shows that MEDICUS is currently the best known teleradiology system. Cost reductions are already obvious, but additional research has to be performed in this field. An even more powerful commercial successor is currently under construction at the Steinbeis-Transferzentrum Medizinische Informatik in Heidelberg.

As the gap between memory and processor speeds continues to widen, cache efficiency is an increasingly important component of processor performance. Compiler techniques have been used to improve instruction and data cache performance for virtually indexed caches by mapping code and data with temporal locality to different cache blocks. In this

A determinação dos mecanismos básicos e dos critérios de implantação de um pacote de software de rede num sistema operacional específico é apresentada em detalhe. Em seguida, são analisadas alternativas de arquitetura de rede susceptíveis de implantação no sistema alvo, no caso, uma arquitetura particular e outra seguindo o modelo de referência RM-OSI/ISO. Finalmente, o detalhamento da arquitetura escolhida, RM-OSI/ISO é apresentado com considerações sobre sua implantação e o escopo das aplicações suportadas.

For the last decade or so, the biggest category of the IT investment has unarguably been Enterprise Resource Planning (ERP). Most of the bigger corporations in the developed countries have implemented ERP systems with an aim to achieving competitive edge in their respective business areas. Now that the top end of the ERP market has been saturated, the main interest has moved to non-commercial sectors such as universities and small and medium-sized enterprises (SMEs). These organisations have not been able to benefit directly from the ERP revolution because an ERP implementation requires huge resources and entails high risks.

Energy-efficiency is key to meet lifetime requirements of Wireless Sensor Networks (WSN) applications. Today's run-time platforms and development environments leave it to the application developer to manage power consumption. For best results, the characteristics of the individual hardware platforms must be well understood and minutely directed. An Operating System (OS) with suitable programming abstractions can micromanage power consumption of resources. We demonstrate with the Mote Runner platform how the inherent overhead of managed application code is compensated for by a platform-independent communication API together with sleep optimizations. The proposed abstractions and optimizations can be applied to other modern sensor network platforms. To quantify the effectiveness of our approach, we measured the energy efficiency of a realworld WSN application using a custom TDMA communication protocol fully implemented on both Mote Runner and TinyOS. Mote Runner's power management and sleep phase optimizations outperforms TinyOS in our test application for duty cycles below 10% on the Iris hardware.

During the last decade, operational monitoring and forecasting systems have been developed in all the European seas. The exchange of data and products and the development of services for a wide community of users pose some fundamental issues, whose solution has become a priority in integrated and GMES referring projects, such as the MERSEA European project. These projects aim to develop a European system for operational monitoring and forecasting on global and regional scales of ocean physics, biochemistry and ecosystems. GMES system and its operational projects need to federate resources and expertise coming from diverse organizations working on different Earth Sciences fields (e.g. satellite data processing, in situ observing systems, data management, ocean and ecosystem modeling, etc.). Therefore, it is required a Marine Information Management (MIM) system capable of facilitating the regular real-time exchange of high quality information, data and products. Moreover, MIM system must provide appropriate information for a wide range of external users both in real-time and delayed mode. In this paper an architecture based on the OPeN-DAP/THREDDS technology is proposed as a solution for these operational systems. In this context, a catalog merging solution is introduced for the MIM system, which results in the design and development of the THREDDS Dataset Merger (TDM): a set of services meant to merge THREDDS Dataset Inventory Catalogs, so to achieve a unique catalog service for a whole database federation. TDM service merges distributed and autonomous THREDDS catalogs in order to work out a virtual merged catalog. The TDM service was extended in order to provide automatic catalogs synchronization. This service allows extending the pull-based TDM paradigm to support push-based applications. Some security issues are also considered.

Performance is a pervasive quality of software systems; everything affects it, from the software itself to all underlying layers, such as operating system, middleware, hardware, communication networks, etc. Software Performance Engineering encompasses efforts to describe and improve performance, with two distinct approaches: an early-cycle predictive modelbased approach, and a late-cycle measurement-based approach. Current progress and future trends within these two approaches are described, with a tendency (and a need) for them to converge, in order to cover the entire development cycle.

The formal analysis described here detects two so far undetected real deadlock situations per thousand C source files or million lines of code in the open source Linux operating system kernel, and three undetected accesses to freed memory, at a few seconds per file. That is notable because the code has been continuously under scrutiny from thousands of developers' pairs of eyes. In distinction to model-checking techniques, which also use symbolic logic, the analysis uses a "3-phase" compositional Hoare-style programming logic combined with abstract interpretation. The result is a customisable post-hoc semantic analysis of C code that is capable of several different analyses at once.

While many theoretical arguments against or in favor of open source and closed source software development have been presented, the empirical basis for the assessment of arguments and the development of models is still weak. Addressing this research gap, this paper presents the first comprehensive empirical investigation of published vulnerabilities and patches of 17 widely deployed open source and closed source software packages, including operating systems, database systems, web browsers, email clients, and office systems. The empirical analysis uses comprehensive vulnerability data contained in the NIST National Vulnerability Database and a newly compiled data set of vulnerability patches. The results suggest that it is not the particular software development style that determines the severity of vulnerabilities and vendors' patching behavior, but rather the specific application type and the policy of the particular development community, respectively.

ABSTRACT This article deals with the role of server operating systems (SOS) in sustaining availability and reliability of contemporary E-business. A framework that can be used in identifying the most critical SOS functions and selecting appropriate SOS platform is presented.

This paper presents methods towards making an operating system malicious activity conscious. In addition to the existing focus of operating systems mainly on resource and user management, we propose that an operating system should also try to prevent the execution of malicious code such as viruses and worms. Exploiting the fact that malicious code/programs require services from the operating system provided via system calls, we hypothesized and demonstrated that the operating system is the ideal location where malicious code prevention has to be attempted. Since computer security has a human element as well, in our approach we followed control of malicious activity by forcing them to run with the consent of the user. Our proposal is implemented and tested in a Linux environment and showed good results.

workloads is the first step in tuning disk subsystem performance. This paper presents an efficient implementation of disk I/O workload characterization using online histograms in a virtual machine hypervisor-VMware ESX Server. This technique allows transparent and online collection of essential workload characteristics for arbitrary, unmodified operating system instances running in virtual machines. For analysis that cannot be done efficiently online, we provide a virtual SCSI command tracing framework. Our online histograms encompass essential disk I/O performance metrics including I/O block size, latency, spatial locality, I/O interarrival period and active queue depth. We demonstrate our technique on workloads of Filebench, DBT-2 and large file copy running in virtual machines and provide an analysis of the differences between ZFS and UFS filesystems on Solaris. We show that our implementation introduces negligible overheads in CPU, memory and latency and yet is able to capture essential workload characteristics.

This manuscript describes the Sensor Web Adaptive Resource Manager (SWARM) project. The primary focus of the project is on the design and prototyping of middleware for managing computing and network resources in a way that enables the information systems of satellite conste llations to provide realtime performance within dynamic environments. The middleware has been prototyped, and it has been evaluated by employing it to manage a pool of distributed resources for the ITOS (Integrated Test and Operations System) satellite command and control software system. The design of the middleware is discussed and a summary of the evaluation effort is provided.

Software-based global positioning system (GPS) receivers perform all the baseband signal processing and the high level functions on a general purpose processor. The heavy computational loads of the signal correlation in baseband processing make it difficult for software receivers to operate in real time. In order to improve the real-time performance, an enhanced bit-wise parallel algorithm has been developed in this study. The enhanced algorithm has been implemented and tested in a 12 channels real-time GPS software receiver. The system consists of a radio frequency front end, a data acquisition board and software that runs on a laptop with a Pentium-M 1.5 GHz processor running the Window Ò XP operating system. The data acquisition board packs the 2-bit intermediate frequency samples with a 2-bit in/8-bit out shift register and transfers the packed samples to laptop through a USB port. The software running on the laptop performs all the baseband and navigation processing in real time. The test results show that the enhanced algorithm significantly improves the real-time performance of the software receiver by reducing the computational operations for signal correlation by 50% compared with the existing bit-wise parallel algorithm. Furthermore, the enhanced algorithm also reduces the amount of required memory for storing data for signal correlation.

Kerberos has become a mature, reliable, secure network authentication protocol. Kerberos is based on secret key encryption technology. It is the native network authentication protocol in the Microsoft Windows 2000 operating system and may be a candidate for use as a general-purpose authentication protocol for large user communities on the Internet. Several proposals have been developed that add public key

Scheduling of many different kinds of activities takes place in distributed real-time and multimedia systems. It includes scheduling of computations, window services, filesystem management, I/O services and communication protocol processing. In this paper, we investigate the ...

The Bologna Declaration and the implementation of the European Higher Education Area are promoting the use of active learning methodologies such as cooperative learning and project based learning. This study was motivated by the comparison of the results obtained after applying Cooperative Learning (CL) and Project Based Learning (PBL) to a subject of Computer Engineering. The fundamental hypothesis tested was whether the academic success achieved by the students of the first years was higher when CL was applied than in those cases to which PBL was applied.

This work presents several approaches for designing the memory management component of self-stabilizing operating systems. We state the requirements a memory manager should satisfy. One requirement is eventual memory hierarchy consistency among different copies of data residing in different (level of) memory devices e.g., RAM and Disk. Another requirement is stabilization preservation a condition in which the memory manager ensures that every process that is proven to stabilize independently, stabilizes under the (self-stabilizing scheduler and) memory manager operation too. Three memory managers that satisfy the above requirements are presented. The first allocates the entire physical memory to a single process at every given point in time. The second one uses fixed partition of memory between processes, while the last one uses memory leases for dynamic memory allocations. The use of leases in the scope of memory allocation in the operating system level is a new and important aspect of our self-stabilizing memory management.

Network experiments are essential for assessing and validating new networking technologies, architectures and protocols. These assessments have long been performed using network simulators. But it clearly appeared that the results got in simulations cannot be reproduced in real environment. Emulators can hardly integrate accurate models of all networking components, end host operating systems and applications what leads to unrealistic simulations very often. Therefore, some work has been issued for developing real experiment platform and network emulators. This paper addresses the motivations that raised the design and development of such an experimental platform at LAAS -laasnetexp -and describes its constituting feature s and components. It is in particular detailed how experimental conditions can be fully controlled for reproducible and easy to analyze experiments. Last, this paper describes how realistic conditions can be set-up in experiments by using the results of actual Internet and Internet traffic characterization, analysis and modeling. Such information helps to realistically configure emulators as well as define realistic traffic generators. The realism of such experiments is illustrated as a demonstration of the interest of laasnetexp for networking research.