Requirements for a COTS software component: A case study

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.     

基于COTS器件的高费效比商业卫星计算机研究

对国内外基于COTS(Commercial Off-The-Shelf)器件的商业卫星计算机进行了研究。针对商业卫星公司对卫星可靠性、运算性能、成本控制、研发周期等要求和实际空间运行环境,分析了目前国内外商用卫星的设计模式和特点,提出一种基于汽车级COTS器件的商业卫星单板计算机系统。在可靠性设计上采用了EDAC、双核Lock-Step等技术,选用单粒子免疫的器件的MRAM和反熔丝FPGA,在保证计算机系统安全性、可靠性、成本控制和运算性能的同时,避免了多核或多处理器冗余加固方案导致的额外软件开发成本,缩短产品研发周期。研究对基于COTS器件的商业卫星计算机的可靠性设计有一定参考价值。     

空间探测中基于COTS部件的软件容错技术

随着航天活动的发展，空间探测任务对于高性能计算的需求越来越明显，高性能的空间超级计算机成为决定下一代空间探测计划成败的关键之一。专用的防辐射计算部件不仅价格昂贵，而且在性能上远远落后于同时代的商用部件（COTS）。使用软件容错技术在COTS部件上搭建空间超级计算机，在达到和专用防辐射部件同样的容错效果的前提下，能够大幅度降低成本，提高性能和性能／功耗比。美国国家宇航局和斯坦福大学的实验已经验证，使用COTS部件有助于实现低成本高效能的下一代空间科学探测计划。     

Mars microrover navigation: Performance evaluation and enhancement

In 1996, NASA will launch the Mars Pathfinder spacecraft, which will carry an 11 kg rover to explore the immediate vicinity of the lander. To assess the capabilities of the rover, as well as to set priorities for future rover research, it is essential to evaluate the performance of its autonomous navigation system as a function of terrain characteristics. Unfortunately, very little of this kind of evaluation has been done, for either planetary rovers or terrestrial applications. To fill this gap, we have constructed a new microrover testbed consisting of the Rocky 3.2 vehicle and an indoor test arena with overhead cameras for automatic, real-time tracking of the true rover position and heading. We create Mars analog terrains in this arena by randomly distributing rocks according to an exponential model of Mars rock size frequency created from Viking lander imagery. To date, we have recorded detailed logs from over 85 navigation trials in this testbed. In this paper, we outline current plans for Mars exploration over the next decade, summarize the design of the lander and rover for the 1996 Pathfinder mission, and introduce a decomposition of rover navigation into four major functions: goal designation, rover localization, hazard detection, and path selection. We then describe the Pathfinder approach to each function, present results to date of evaluating the performance of each function, and outline our approach to enhancing performance for future missions. The results show key limitations in the quality of rover localization, the speed of hazard detection, and the ability of behavior control algorithms for path selection to negotiate the rock frequencies likely to be encountered on Mars. We believe that the facilities, methodologies, and to some extent the specific performance results presented here will provide valuable examples for efforts to evaluate robotic vehicle performance in other applications.     

Safety-critical systems built with COTS

In the rail transportation industry competitive pressure has led to the increased use of COTS (commercial off-the-shelf equipment in safety critical systems), making it imperative that we extend proven safety techniques to COTS based systems as well. To this end, we have developed the Vital Framework (V-Frame), which is used to develop a safety critical platform from COTS hardware and software. The key technologies in this framework are formal methods, information redundancy, a proprietary data format, and a concurrent checking scheme. Combining these technologies results in a real time, checkable correctness criterion that is a signature of the application's algorithm structure and is independent of both the hardware and the operating system. V-Frame's most significant attribute is that the fail safe properties of applications do not require the firmware to be correct: the application will operate in a fail safe (or vital) manner even if there are design faults in the operating system and/or the hardware fails. This does not mean that the application does not have to be correctly specified and designed. Formal methods are appropriate in the design of safety critical COTS systems because a generic processing environment is analogous to a formal system: it is designed to apply well defined transformation rules to inputs     

Beyond cost: the drivers of COTS application value

In the early days of business computing, most software was written from scratch. Companies created applications to automate key business processes such as American Airlines' legendary Sabre computerized reservation system. Such leading-edge applications were challenging to develop. While companies still build custom applications today, the advent of COTS software over the past 30 years has dramatically changed the way they acquire software. In an extensive study involving 126 organizations, we analyze how management information systems (MIS) managers evaluate key attributes of COTS software. The results provide surprising insights into the COTS software characteristics that buyers value most. The findings have important implications for COTS buyers and suppliers. For buyers, we provide an assessment framework for evaluating COTS software. For companies that develop COTS software, we provide insights into what attributes their prospective customers value most.     

一种高可靠的工业级星载计算机及其引导设计

传统星载计算机通常采用价格昂贵的高质量等级CPU和存储器芯片,用于保证系统的可靠性;因制造成本和研制周期等方面的限制,商业卫星计算机更倾向于采用商业现货器件(COTS),但其可靠性和安全性会随之降低;采用工业级SmartFusion2处理器芯片,提出一种低成本的星载计算机最小系统架构,并通过工业级存储器异构备份的方式,显著提高系统可靠性;在星载计算机软件设计中,应用软件会采用三模冗余的方式提高可靠性,但引导软件往往只有单份;为了避免引导软件的单节点故障效应,针对SmartFusio2星载计算机架构,提出一种基于多TMR副本的片外启动方法,此启动方法可进一步提高工业级星载计算机的可靠性和安全性,并成功用于多个型号商业卫星。     

Low-cost simulated MIG welding for advancement in technical training

The simulated MIG lab (sMIG) is a training simulator for Metal Inert Gas (MIG) welding. It is based on commercial off the shelf (COTS) components and targeted at familiarizing beginning students with the MIG equipment and best practices to follow to become competent and effective MIG welders. To do this, it simulates the welding process as realistically as possible using standard welding hardware components (helmet, gun) for input and by using head-tracking and a 3D-capable low-cost monitor and standard speakers for output. We developed a simulation to generate realistic audio and visuals based on numerical heat transfer methods and verified the accuracy against real welds. sMIG runs in real time producing a realistic, interactive, and immersive welding experience while maintaining a low installation cost. In addition to being realistic, the system provides instant feedback beyond what is possible in a traditional lab. This help students avoid learning (and unlearning) incorrect movement patterns.     

Exploring the effectiveness of commercial and custom-built games for cognitive training

There is increasing interest in quantifying the effectiveness of computer games in non-entertainment domains. We have explored general intelligence improvements for participants using either a commercial-off-the-shelf (COTS) game, a custom do-it-yourself (DIY) training system for a working memory task or an online strategy game to a control group (without training). Forty university level participants were divided into four groups (COTS, DIY, Gaming, Control) and were evaluated three times (pre-intervention, post-intervention, 1-week follow-up) with three weeks of training. In general intelligence tests both cognitive training systems (COTS and DIY groups) failed to produce significant improvements in comparison to a control group or a gaming group. Also neither cognitive training system produced significant improvements over the intervention or follow-up periods.     

Modeling uncertainty in software engineering using rough sets

Uncertainty casts a shadow over all facets of software engineering. This negative meta-property is found in every aspect of software including requirement specifications, design, and code. It can also manifest itself in the tools and engineering practices employed, and in the off-the-shelf software incorporated into the final product. Unfortunately, it is often the case that software engineers ignore these sources of uncertainty or abstract them away. Perhaps this is because there is insufficient understanding of this uncertainty, and no universal techniques for handling its many forms. This paper focuses on the issues of uncertainty in software engineering. It further describes a rough set framework for making decisions in the face of such uncertainty and inconsistency. In particular, we show how to induce rule-based decision making from uncertain information in software engineering applications. Moreover, a freely available tool, Rosetta, is employed to automate the decision-making process. NASA has mandated the use of commercial off-the-shelf (COTS) solutions where possible. But in commercial real-time operating systems certain attributes are uncertain, even where published information is available. Therefore, the selection of a commercial real-time operating system for an embedded system is the software engineering problem with which we explain the rough set decision-making process.     

NASA's Pathfinder data set programme: land surface parameters

The Pathfinder data set concept was initiated by the Earth Observing System (EOS) Program Office at the National Aeronautics and Space Administration (NASA) Headquarters to address how existing satellite-derived data sets could be used for global change research prior to the availability of EOS data. They are denned as long time-series satellite data sets capable of stable calibration which can be reprocessed using a community-consensus set of algorithms

In October 1990 NASA and the National Oceanic and Atmospheric Administration (NOAA) initiated a joint Pathfinder program. Data from three NOAA and one Defense Meteorological Satellite Program (DMSP) instruments have been designated as Pathfinders under this activity. In addition to this joint effort, NASA has also initiated a Pathfinder development effort for data from both Landsat and the Scanning Multichannel Microwave Radiometer (SMMR) flown on NASA's Nimbus-7 satellite

The AVHRR Pathfinder was the first set of projects to be initiated. Because the data have distinct disciplinary user heritages and expertise associated with the atmosphere, ocean, and land, three separate Science Working Groups were formed to recommend and comment on all stages of data set design and development. One of these groups is the AVHRR Land Pathfinder Science Working Group. Additionally, low resolution land surface parameters will be produced by the SSM/1 and SMMR Pathfinder projects. A Global 1 km Data Set Project, in the spirit of Pathfinder and partially funded with NASA Pathfinder funding, was begun in October 1991 and began collecting data continuously on a daily basis on 1 April 1992

One of the goals of Pathfinder data set production, to make available consistent long-time series data sets for global change research, has encouraged substantial interdisciplinary use of the data, and therefore consideration of problems of data fusion or integration. Work in producing the Pathfinder data sets has exposed important technical problems which scientists encounter impeding interuse of data sets. Presently, an experiment involving scientists and systems engineers working with several Pathfinder data sets is exploring possible solutions to some of these technical problems.     

Synthesizing safe control-command systems out of reusable components

This paper presents a safe design method for control-command embedded systems. It investigates the problem of building control-command systems out of Commercial off the shelf (COTS) components. The design method proposed uses in synergy the formal verification (FV) and the Discrete Controller Synthesis (DCS) techniques. COTS are formally specified using temporal logic and/or executable observers. New functions are built by assembling COTS together. As the COTS assembly operation is seldom error-free, behavioral incompatibilities may persist between COTS. For these reasons, COTS assemblies need to be formally verified and if errors are found, an automatic correction is attempted using DCS. The control-command code generated by DCS needs hardware specific post-processing: a structural decomposition, followed by a controllability assessment, followed by a dedicated formal verification step, ensuring that no spurious behavior is added by DCS. The resulting system is ready for hardware (e.g. FPGA) implementation.     

Assessing COTS software in a certifiable safety-critical domain

Abstract.  Commercial off-the-shelf (COTS) software solutions have become commonplace in many domains, including the military, because they can provide standardized functionality with more responsiveness, a shorter time-to-market and at lower costs than custom-made solutions. In one domain, however, that of certifiable safety-critical applications, COTS software has not been adopted. One particular type of certifiable safety-critical domain, the civil air transport industry, is under pressure to reduce cost and time-to-market while simultaneously increasing safety. Therefore, the use of COTS software, rather than exclusive reliance on custom-made software, would appear to be a solution worthy of investigation. This study examines the certifiability of COTS software, its technical feasibility in this environment, and the ability to achieve the expected responsiveness, time-to-market and cost benefits. A detailed evaluation of COTS software and domain-specific certification requirements is used to demonstrate that the certification of COTS-based systems is possible. A prototype COTS-based system (built upon a number of COTS components) is created to illustrate the technical feasibility of such a system in the civil air transport domain. Expected benefits from COTS solutions are evaluated both by examining process artefacts from the development of the COTS-based system and by comparing this development process with the domain's traditional custom-development process.     

COTS software: the economical choice?

A new trend in software commerce is emerging: generic software components, also called commercial off the shelf components, that contain fixed functionality. COTS components can be incorporated into other systems still under development so that the developing system and the generic components form a single functional entity. The role of COTS components is to help new software systems reach consumers more quickly and cheaply. Because arriving last to market spells sudden death in the software industry, any approach that carves days or weeks from a development schedule is worth considering. The article gives advice on taking the COTS option and the management decisions that have to be made     

基于COTS的宇航计算单元冗余架构可靠性研究

随着商业航天的发展,为了能以更低成本使宇航计算单元得到应用,需要结合设计成本、预期寿命、实时性和系统复杂度等因素,对不同计算单元冗余架构的可靠性进行评估;目前在基于高性能商用货架(COTS,commercial off-the-shelf)器件的宇航计算单元研究多满足于工程应用,缺乏关于对不同架构可靠性的对比;首先,针对几种不同冗余计算单元冗余架构,简单介绍具体的拓扑结构和工作方式;其次,根据工作方式给出了他们的故障状态转移图;最后,根据上述几种架构,运用马尔可夫模型理论,对这些计算单元结构进行可靠性建模,在考虑失效率和维修率两个参数对系统可靠性影响的情况下,并以一个虚拟的长时期任务为背景对各结构的可靠性指标进行了评价;仿真结果为更低成本基于COTS器件制造宇航计算单元提供了设计支撑。     

COTS-based systems top 10 list

Presents a COTS-based system (CBS) software defect-reduction list as hypotheses, rather than results, that also serve as software challenges for enhancing our empirical understanding of CBSs. The hypotheses are: (1) more than 99% of all executing computer instructions come from COTS products (each instruction passed a market test for value); (2) more than half the features in large COTS software products go unused; (3) the average COTS software product undergoes a new release every 8-9 months, with active vendor support for only its latest three releases; (4) CBS development and post-deployment efforts can scale as high as the square of the number of independently developed COTS products targeted for integration; (5) CBS post-deployment costs exceed CBS development costs; (6) although glue-code development usually accounts for less than half the total CBS software development effort, the effort per line of glue code averages about three times the effort per line of developed applications code; (7) non-development costs, such as licensing fees, are significant, and projects must plan for and optimize them; (8) CBS assessment and tailoring efforts vary significantly by COTS product class (operating system, database management system, user interface, device driver, etc.); (9) personnel capability and experience remain the dominant factors influencing CBS development productivity; and (10) CBS is currently a high-risk activity, with effort and schedule overruns exceeding non-CBS software overruns, yet many systems have used COTS successfully for cost reduction and early delivery     

基于Globus Toolkit网格信息服务的研究及应用

为了提高校园中资源的利用率,方便管理校园中的网络设备和资源,进行信息整合,实现资源共享,基于GlobusToolkit搭建了校园网格。在充分对比基于Web Service监控发现系统和监控发现系统的基础上,重点研究了基于WebService监控发现系统的工作机制和工作原理。利用网格中间件Globus Toolkit4.2.1中的基于Web Service监控和发现系统搭建了校园网格信息服务,实现了对三个校区集群资源信息和调度信息的监控,实现了对数据传输的监控,管理员可以通过网页的形式方便查看网络设备运行状态,掌握整个网络的运行状态。     

Clock synchronization for distributed media applications

Current video wall technology relies on custom processing hardware to drive the individual display channels. This hardware is both expensive to design and to maintain. Given that modern off‐the‐shelf computers have a significant amount of computing power, future video displays can be driven with this hardware at a lower cost. By using mass‐produced computers and a standard commercial operating system, the benefits of economies of scale can be brought to the custom video wall market. This paper describes a Windows library that provides the synchronized timing support necessary to drive a video wall with consumer hardware. The goal is to provide a key building block for the media software that will process the incoming video stream. This library exports several interfaces to the host software and provides support for synchronized timers, a synchronized clock, and reliable multicast messaging. The library uses common Windows APIs and protocols for maximum interoperability and portability. Through empirical testing, we are able to show that synchronization between any two machines in the system can be maintained to within 12 ms when run on Windows XP SP2. This synchronization is also shown to be consistent even when there is a heavy load on the processor. As a result, this library will successfully allow a commercial video wall to be driven from media software running on consumer hardware and software. Copyright © 2007 John Wiley & Sons, Ltd.     

Performance techniques for COTS systems

COTS components can provide much of the functionality of distributed information systems. These components range from stand-alone elements, such as a Web server or database system, to platform software or an operating system, to embedded functional components, such as a calendar manager or an inventory-management JavaBean. COTS-based software performance demands more powerful investigative methods than custom software. This performance is particularly important when components include internal concurrency, as is the case in J2EE application servers. We need component-based performance modeling to drive system planning, using layered modeling when considering concurrency, and we need high-level traces to capture measurements related to these structures and diagnose performance issues.     

The potential of the NASA GAC Pathfinder product for the creation of global thematic data sets: the case of biomass burning patterns

NASA's Advanced Very High Resolution Radiometer Global Area Coverage (GAC) Pathfinder data are compared with the European Commission's GAC data set, as a step towards validation of this new NASA product. Results show that the NASA data have considerable potential for describing global land surface processes, such as biomass burning patterns.