面向对象数据库无缝的C^＋＋应用编程界面

关系数据库与程序设计语言之间的松散耦合存在着编程范型及类型系统两方面的失配，是提高数据库应用软件之质量和生产率的极大障碍，面向对象数据库（ＯＯＤＢ）与程序设计语言（ＰＬ）的无缝结合旨在消除这种失配，本文以面向对象数据库管理系统原型ＯＳＣＡＲ为背景，提出ＯＯＤＢ与ＰＬ无缝结合的基本准则，ＯＯＤＢ无缝Ｃ＾＋＋应用编程界面的对象持久性模型，以及实现ＯＯＤＢ无缝Ｃ＾＋＋应用编程界面的关键技术。     

XDOODB：一种支持关系模型和数据库方法的OODBMS

本文所述的研究工作，是在ＯＯＤＢＭＳ中同时支持面向对象数据模型和关系数据模型，实现包括对象操作（即数据库方法）在内的同一体化对象管理，并研制了一个相应的原型系统ＸＤＯＯＤＢ。在ＸＤＯＯＤＢ中，我们设计和实现了一种基于ＳＱＬ的数据库语言ＯＳＱＬ，提出了虚拟方法的概念，实现了一种Ｃ＋＋预编译器，使之可自动产生虚拟方法体，所提供的方法服务器以对用户透明的方式可进行数据库方法的存储、动态加载和运行，并采用     

基于PCI总线的DVB流合成及传输系统实现

该文讨论了利用Ｓ５９２０和ＰＬＤ实现ＴＭ３２０Ｃ３２与ＰＣＩ总线间数据传输,以及用协处理器完成ＤＶＤ流合成的具体方案;结合设计给出了 ＭＡＸ＋ＰＬＵＳⅡ软件中 ＦＩＦＯ模块的使用和操作时序。针对 ＤＶＢ传输流形成,讨论了在复杂时序逻辑设计中,使用同步触发和２倍输入时钟方式消除毛利的产生,结果表明这种方法是很有效的。     

一个基于关系数据库的面向对象关系数据库管理系统OORDBMS

面向对象数据库系统被称为一代数据库系统，已有为软件研制和开发领域中的热点。本文提出了一种在关系数据库的基础上实现面向对象关系数据库管理系统（ＯＯＲＤＢＭＳ）的设计思想，并介绍我们在ＦＯＸＢＡＳＥ＋基础上实现ＯＯＲＤＢＭＳ的研究工作。     

MFOXPLUS＋数据库系统插入记录的链表方法

ＭＦＯＸＰＬＵＳ＋数据库系统插入记录的链表方法中国工商银行洪泽县支行罗升，陈洪森ＭＦＯＸＰＬＵＳ＋１００％地与ｄＢＡＳＥⅢ兼容；以其快捷的速度、全新的功能在微机数据库管理系统（Ｄ３Ｍ８）中，得到广泛的运用。用户在使用ＭＦＯＸＰＬＵＳ＋数据库管理系统，...     

WINDOWS应用程序与FOXPRO间的DDE数据通讯

本文介绍了ＷＩＮＤＯＷＳ中ＤＤＥ通讯的原理，讨论了如何利用这一技术实现ＦＯＸＰＲＯ与ＷＩＮＤＯＷＳ应用程序的实时数据交换，并用ＶＩＳＵＡＬ Ｃ＋＋和ＦＯＸＰＲＯ开发了示例程序。     

用VISUAL FOXPRO设计多媒体播放器

本文介绍了利用ＶＩＳＵＡＬＦＯＸＰＲＯ的应用程序接口ＦＯＸＴＯＯＬＳ调用ＷＩＮＤＯＷＳ的ＤＬＬ库开发多媒体播放器的原理及实现技术，利用该播放器可以对波形文件（．ＷＡＶ），数字音乐，（．ＭＩＤ），视频图象（．ＡＶＩ）动画（．ＦＬＡ）音频，压缩视频（．ＭＰＧ）Ｖ－ＣＤ视频，（．ＤＡＴ）等进行控制和播放。     

用VXD实现WIN95／98下的DMA操作

研究并介绍在ＷＩＮＤＯＷＳ９５／９８环境下,ＶｔｏｏｌｓＤ如何支持直接内存读写（ＤＭＡ）操作以及如何调用相关的Ｃ＋＋类与成员函数实现该操作,给出了虚拟设备驱动程序（ＶＸＤ）实现ＤＭＡ操作的编程实例。     

配电自动化系统实时分布式数据库

本文介绍作者为配电自动化系统研制一个实时分布式数据库管理系统（ＲＤＤＢ），ＲＤＤＢ是在以太网上，中文ＷＩＮＤＯＷＳＮＴ（Ｖ４．０）环境下，以ＭｉｃｒｓｏｆｔＳＱＬＳｅｒｖｅｒ为后台，利用ＭｉｃｒｓｏｆｔＶｉｓｕａｌＣ＋＋（Ｖ４．０）开发的，它采用层次数据模型，重复式数据设置方式；用Ｃｌｉｅｎｔ／Ｓｅｒｖｅｒ工作方式与应用程序交换数据，用ＷＩＮＤＯＷＳＮＴ的多线程，管道和邮件槽技术实现并行工作，充分     

适用于VLSI数据管理和工具控制的面向对象方法

本文提出了一个能有效地支持ＶＬＳＩ设计的面向对象的方法，它主要包括数据的管理和工具的控制。它采用一个数据模型（称为ＤＴＯ模型）刻划设计对象，由四个基本参量（设计对象类，设计方法，历史版本，等价视图）唯一确定，为了进行设计方法的描述，开发了一种描述工具特征的设计方法扩展描述语言（ＤＭＥＬ）。采用设计事件堆栈的方法用于工具的控制，实现了动态的设计流程调度机制（ＤＤＦＳ）。ＤＴＯ模型结合ＤＤＦＳ，成功地     

MIDS／BUAA存储管理子系统的设计

存储管理（特别是辅存管理）是任何一个数据库系统的物理实现层，持久性若不最终落实到辅存上，就是一句空话．本文首先讨论了将程序设计语言和持久对象进行集成的３种途径；然后介绍了ＭＩＤＳ存储管理子系统ＳＭＳ（ＳｔｏｒａｇｅＭａｎａｇｅｍｅｎｔＳｕｂｓｙｓｔｅｍ）的设计：（１）ＳＭＳ的体系结构，（２）ＭＩＤＳ对象的存储结构，（３）对象标识的设计，（４）簇聚与索引，（５）持久性的实现，（６）动态地址转换．     

反射对象的概念、结构和实现

本文较系统地介绍了面向对象数据库语言ＲＯＬ中对象的计算反射的思想和实现方法．反射对象的引入是为了解决对象库中复杂的管理问题，并为设计智能化程度更高的对象提供一个良好的基础．本文还讨论了反射结构带来的问题，即封装性间题和效率问题，以及一种解决方法．     

A practical approach to data modelling in spatial applications

The storage and manipulation of spatial data requires a different style of support from that normally found in commercial database systems. This paper explores the use of the functional data model and the high level language Daplex to provide an integrated tool for the conceptual modelling of spatial data and the manipulation of data values. Importance is attached to allowing dynamic schema definition and to the provision of abstract data types to support spatial objects. The implementation comprises three separate modules and uses an underlying relational DBMS to store all metadata and data values. This modular design has enabled the user interface, Daplex language and storage aspects of the software to be developed independently, creating a system which has already proved to be easily portable. Consideration has also been given to ways of improving system performance.     

Multidimensional array I/O in Panda 1.0

Large multidimensional arrays are a common data type in high-performance scientific applications. Without special techniques for handling input and output, I/O can easily become a large fraction of execution time for applications using these arrays, especially on parallel platforms. Our research seeks to provide scientific programmers with simpler and more abstract interfaces for accessing persistent multidimensional arrays, and to produce advanced I/O libraries supporting more efficient layout alternatives for these arrays on disk and in main memory. We have created the Panda (Persistence AND Arrays) I/O library as a result of developing interfaces and libraries for applications in computational fluid dynamics in the areas of checkpoint, restart, and time-step output data. In the applications we have studied, we find that a simple, abstract interface can be used to insulate programmers from physical storage implementation details, while providing improved I/O performance at the same time.(A preliminary version of this paper was presented at Supercomputing '94.)     

Architecture of the ORION next-generation database system

Various architectural components of ORION-1 and ORION-1SX are described and a review of the current implementation is provided. The message handler receives all messages sent to the ORION system. The object subsystem provides high-level data management functions, including query optimization, schema management, long data management (including text search) and support for versionable objects, composite objects, and multimedia objects. The transaction management subsystem coordinates concurrent object accesses and provides recovery capabilities. The storage subsystem manages persistent storage of objects and controls the flow of objects between the secondary storage device and main memory buffers. In ORION-1, all subsystems reside in one computer. The ORION-1SX architecture is significantly different from ORION-1 in the management of shared data structures and distribution of these subsystems and their components     

Programming persistence in chi

The ways in which a persistent programming language allows the reuse of data and code objects by preserving them as persistent objects is discussed. The programming language chi , which supports persistent programming, is described. The language is innovative in that it elevates capabilities to the programming level and gives the programmer a convenient way to express which objects are persistent independently of the type of object. Thus, it provides orthogonal persistence. A further advantage that follows from such use of capabilities is that chi provides an implementation path for persistence, even upon architectures that do not support capabilities directly.<>     

Development of a physically behaved robot work cell in virtual reality for task teaching

Robot task teaching on a real work cell is expensive and sometimes risky. This cost and risk can be avoided by using virtual reality technology. Using the simulated environment in virtual reality (VR), the operator can practise, explore and preview the operations for possible problems that might occur during implementation. It is therefore of practical importance to build the virtual robot work cell in VR that can facilitate the study of the performance of robotic tasks such as robotic assembly. This paper describes our work in incorporating physical behaviours of virtual objects into VR for robot task teaching. To facilitate the task teaching, we developed visual and audio cues which help visualise the dynamic interactions between virtual objects. Dynamic sensing capability is incorporated in the simulated environment. A simplified force sensor is modelled and simulated. The physical behaviours of the virtual objects are simulated using physics-based approach. A virtual robot work cell is built incorporating the developed features and an example for the task teaching is given. The implementation includes view tracking using virtual camera, visual and audio rendering, and the user interface developed in the VR. The current implementation was carried out on a PC-based VR platform, with the programs developed using Watcom C++.     

抗板级物理攻击的持久存储方法研究

为保护文件系统的安全性,提出一种抗板级物理攻击的持久存储方法。利用ARM TrustZone技术构建持久存储架构,实现内存保护机制和持久存储保护服务,提高文件系统的物理安全性。基于片上内存（OCM）在可信执行环境（TEE）中的内核层建立内存保护机制,保证TEE的可信应用能够抵抗板级物理攻击。基于TEE的内存保护机制实现保护文件系统中敏感数据的持久存储保护服务,确保文件系统的机密性和完整性。在物理开发板上实现持久存储架构的原型系统,使用基准测试工具对原型系统进行性能评估,并分析性能损耗的原因。测试结果表明,内存保护机制在保护TEE系统物理安全性时引入的时间开销会随着OCM的增大而减小,持久存储保护服务在保护数据量较小的敏感数据时产生的时间开销在用户可接受范围内。     

QuickStore: A high performance mapped object store

QuickStore is a memory-mapped storage system for persistent C++, built on top of the EXODUS Storage Manager. QuickStore provides fast access to in-memory objects by allowing application programs to access objects via normal virtual memory pointers. This article presents the results of a detailed performance study using the OO7 benchmark. The study compares the performance of QuickStore with the latest implementation of the E programming language. The QuickStore and E systems exemplify the two basic approaches (hardware and soft-ware) that have been used to implement persistence in object-oriented database systems. In addition, both systems use the same underlying storage manager and compiler, allowing us to make a truly apples-to-apples comparison of the hardware and software techniques.     

Replication techniques for speeding up parallel applications on distributed systems

Most methods for programming loosely coupled systems are based on message-passing. Recently, however, methods have emerged based on ‘virtually’ sharing data. These methods simplify distributed programming, but are hard to implement efficiently, as loosely coupled systems do not contain physical shared memory. We introduce a new model, the shared data-object model, that eases the implementation of parallel applications on loosely coupled systems, but can still be implemented efficiently. In our model, shared data are encapsulated in passive data-objects, which are variables of user-defined abstract data types. To speed up access to shared data, data-objects are replicated. This ability to replicate objects is a significant difference with other object-based models (e.g. Emerald and Amber). Also, by replicating logical objects rather than physical pages, our model has many advantages over shared virtual memory systems. This paper discusses the design choices involved in replicating objects and their effect on performance. Important issues are: how to maintain consistency among different copies of an object; how to implement changes to objects; which strategy for object replication to use. We have implemented several options to determine which ones are the most efficient.