Comparison of Memory Management Systems of BSD,Windows, and Linux

AllenĆBradleyMain Processor Module(Cat. No. 1775-L1, -L2)Product DataDescriptionThe main processor module is used in PLC-3 programmable controllersystems to provide:program executionmemory managementThe module occupies two slots in the processor chassis. We recommendthat you install the module in the two, left-most slots. The module receivesits power and communicates with other modules through the PLC-3 chassisbackplane.Two main processor modules are available for your PLC-3 system:cat. no. 1775-L1cat. no. 1775-L212Both main processor modules contain many of the same features (table A). One of the major differences between the two modules is the level of program instructions they are able to execute. The cat. no. 1775-L1 processor module uses the “level 1” instruction set; the 1775-L2 uses the “level 2” instruction set. Refer to table B for a listing of the level 1 and 2 instructions sets.Table ABenefits, Features, and Functions3Table BPLCĆ3 Level 1 and 2 Instruction Sets4Program ExecutionTo provide effective program execution, the main processor module: uses AMD 2903 bit-slice microprocessorsmaintains an on-board I/O image table for high-speed processing of I/O pointsquickly determines if the outputs are true or false using a high-speed program scanning techniqueMemory ManagementThe memory in the main processor module is divided into dedicated, expandable areas:system statussystem pointersmodule statusdata tableuser programmessagessystem symbolsforce tableThis type of memory configuration allows you to:effectively handle a wide variety of applicationseasily increase the size of memory as your application needs changeFlexible Data TableThe data table is one of the most important areas of memory. It is completely expandable provided the memory space is available. The data table consists of the following sections:output imageinput imagetimercounterinteger5floating point (available on the cat. 1775-L2 module only)decimal binary ASCIIhigh order integer (available on the cat. no. 1775-L2 module only)pointer statusLocation Environmental ConditionsG Two, leftĆmost slots(recommended location)MicroprocessorsG 4 AMD 2903's (bit slice)Current Requirements G 9.4A at +5V DC G 40ma at +15V DCG Operating Temperature:0 to 60°C (32 to 140°F)G Storage Temperature:Ć40 to 85° C (Ć40 to 185° F)G Relative Humidity:5 to 95% (without condensation)© 1986 Allen-Bradley CompanyPLC is a registered trademark of Allen-Bradley CompanySpecifications6With offices in major cities worldwideWORLDHEADQUARTERS Allen-Bradley1201 South Second Street Milwaukee, WI 53204 USA Tel: (1) 414 382-2000Telex: 43 11 016FAX: (1) 414 382-4444EUROPE/MIDDLE EAST/AFRICA HEADQUARTERSAllen-Bradley Europe B.V .Amsterdamseweg 151422 AC Uithoorn The Netherlands Tel: (31) 2975/43500Telex: (844) 18042FAX: (31) 2975/60222ASIA/PACIFIC HEADQUARTERSAllen-Bradley (Hong Kong)LimitedRoom 1006, Block B, Sea View Estate 28 Watson Road Hong KongTel: (852) 887-4788Telex: (780) 64347FAX: (852) 510-9436CANADAHEADQUARTERS Allen-Bradley Canada Limited135 Dundas StreetCambridge, Ontario N1R 5X1CanadaTel: (1) 519 623-1810FAX: (1) 519 623-8930LATIN AMERICA HEADQUARTERS Allen-Bradley1201 South Second Street Milwaukee, WI 53204 USA Tel: (1) 414 382-2000Telex: 43 11 016FAX: (1) 414 382-2400As a subsidiary of Rockwell International, one of the world’s largest technologycompanies — Allen-Bradley meets today’s challenges of industrial automation with over 85 years of practical plant-floor experience. More than 11,000 employees throughout the world design, manufacture and apply a wide range of control and automation products and supporting services to help our customers continuously improve quality, productivity and time to market. These products and services not only control individual machines but integrate the manufacturing process, while providing access to vital plant floor data that can be used to support decision-making throughout the enterprise.Publication 1775-2.2 — December, 1984Supersedes Publication 1775-901 — February, 1982PN955096-55。

内存管理说明和类型Memory ManagementExplanation and Types INTRODUCTION TO MEMORY MANAGEMENTMemory management is being regarded as the type of resource management which applies to computer memory. In accordance with the given context, it can be depicted that Memory management is the systematic process in which computer memories are controlled as well as coordinated. Here, different portions are called blocks that are being used for the purpose to run the various programs in order to optimize the overall performance of the system in an effectual way. In the operating system, Memorymanagement plays a vital role. This is because; it assures that the memory of the computer should not be filled with the data. Thus, here we will carry out major discussion on the given aspect only and learn more about the major concepts that are being related to Memory management in an efficient way.KEY AREAS OF MEMORY MANAGEMENTMemory management is being recognized as one of the most complex fields of computer science. Hence, there is a number of techniques have been developed with an aim to make the respective function more efficient in nature. There are three major areas in which the wholeMemory management is divided. The details about the same are depicted below:Hardware memory managementThe very first area related toMemory management is hardware memory management. Herein, it can be depicted that hardware memory management is concerned with the hardware devices. In other words, it can also be said that it is basically related to the electronic devices that store the data of the computer. This includes devices like RAM (Random Access Memory) and caches memory.Operating system memory managementIt is being regarded as another form of Memory management. In this regard, in the operating system, the memory of the computer should be allocated to the user program. However, it isbeing reused by another program when it will be seen that the memory is no longer will be required. Herein, the computer can also pretend that it has more memory to store than the actual capacity. On the other hand, each program that is involved in it has the machine memory. Thus, these are being regarded as the main feature of the virtual memory that is also one of the most important concepts in the computer program.Application memory managementAnother key area of Memory management is application memory management. It basically involves the process of supplying the memory that is being needed for the data structure and program objects. Here, the memory is recycled when it is of no use or when it is no longer required. The application memory does not possess the capability to predict how much memory it willrequire. It basically possesses two types of tasks such as allocations and recycling.Allocation: This happens when the program requests the block of the memory, thus in the respective situation the memory manager has to allocate the blocks out of the larger blocks that have been received by it from the operating system. The respective function which is being performed by the individual is called by the name of allocators.Recycling: It is another task of application memory. In this, the blocks are recycled for the reuse purpose when the memory blocks are allocated and the data which they possess is no longer required. This includes two basic approaches of the recycling memory and theseare manual memory management and automatic memory management.PROBLEMS RELATED TO MEMORY MANAGEMENTHowever, before getting details about the manual and automatic memory management, it is very much important for the individual that they should get the idea about the main problems that are related to the concepts such as Memory management in an effectual way. By getting an idea about the same, some more main details about the Memory management can be gathered. The detail explanations of the same are given below:Premature fees and the dangling pointers: There are many programs that tend to give up thememory, however, they still make an attempt to access it later and behave randomly. The given type of situation is called by the name of premature fees. But, the surviving reference to the memory is called as the dangling pointers in an effectual way.Memory leak: It is another issue that is related to memory management. In accordance with the given context, there are some programs that continually allocate the memory without giving up on the same and as a result of this, they will run out of the memory. The respective type of condition is called as the memory leak.The poor locality of the references: It is another problem that comes from the layout of the allocated blocks. Here, modern hardware and the manager of the operating system handle thememory. The access to the successive memory is faster when it is very much near to the memory locations.Inflexible design: The manager of memory can also cause the server performance problem. This happens when they are being designed with the one use in mind but actually, they are being in different ways. The given problem will occur because here the solutions of memory management tend to make the varied type of assumptions in relation to the manner in which program is being used. Therefore, it is very correct to say that these are some main problems that are related to Memory management.ABOUT MANUAL MEMORY MANAGEMENTAs discussed above also that the recycling can be done in two way and thus in this section discussion is being carried out in relation to the manual memory management. In the given type of memory management, the programmer will tend to have direct control over the memory, thus it has to make a decision that when memory should be recycled. The given thing is usually done by explicit calls with an aim to heap the management functions or it is done through the language construct that will have influence over the control stack. In this regard, it can be depicted that the main feature of the manual memory manager is to state the program to say different things such as “Have the memory has a back” or “am I finished with it”. The advanta ges and disadvantages that are associated with the same are depicted below:Advantages of manual memory management programFor the programmer, it is very much easier to get the idea that what is exactly going onThere is some manual memory manager that tends to perform better when they are short of the memory.Disadvantages of manual memory management programThe programmer here has to write so many codes with an aim to perform the repetitive bookkeeping of the memory in an effectual way.It should form a significant part of any type of module interface.It also requires more memory per the overhead object instead of others.The bugs that are being identified in the manual memory management are very much common. Thus, it can be said that these are some main advantages and disadvantages of manual memory management.ABOUT AUTOMATIC MEMORY MANAGEMENTIt is another type of management. The automatic memory management is basically the type of service or it is the part of the language that automatically recycles that specific memory that the computer program will not use again. The managers of the automatic memory usually perform their job of doing recycling the blocksthat are not reachable from the program variables. However, there are some advantages as well as disadvantages are also being assessed in relation to automatic memory management. The details of the same are given below:Advantages of automatic memory managementThe programmer of the given memory is freed to work on the actual problem in an effectual way.There is very much clear modular interface.The bugs that are being involved in it are not that much.It is more efficient in comparison to the other type of memory management.Disadvantages of automatic memory managementThe memory here is retained, but it is of no use for the users.At present, there is very much limited availability is being seen in relation to the memory manager.BASIC CONCEPTS RELATED TO MEMORY MANAGEMENTIn order to know more about management, it is very much important for the individual that it should have an idea about the main concepts that are related to management. This is because it is by complying with a given type of activity only more details about thememory management can be gathered. The details about the major concepts are depicted below:SwappingThe very first concept of management is swapping. It is the type of process which is being required in memory for the execution purpose. But, many times this happens that there is not enough main memory left with an aim to hold all the active processes in the timesharing type of system. Thus, it is due to the presence of respective aspect only the access processes are being kept on the desk and afterwards, they are brought in for the purpose to run it dynamically. In simple words, it is very right to say that swapping is the systematic process to bring each and every process in themain memory, they are being run for the while and afterwards, they are again being put up in the disk.Contiguous memory allocationIn the contiguous memory allocation, each process is being contained in the single contiguous block of the memory. Herein, it can be said that in the respective approach the memory of the computer is being divided into several fixed partitions. On the other hand, each partition that is being involved in it tends to possess one process. Thus, when the partition is free then in this situation from the process queue, an input is selected and the same thing is loaded in it. The free blocks in the memory are being called by the name of holes. Further,different sets of holes are searched in order to examine which specific hole is good.Memory protectionIt is also considered as another most important aspect. It is basically the type of phenomenon which enables an individual to carry out control over memory access rights on the computers. The main aim of the given protection is to prevent the processing of that specific memory that has not been allocated to it in an effectual way. Thus, it is through this way only it prevents the bugs within the process that is being affected by another process. Further, the results of segmentation faults are being used in order to disrupt the whole process.Memory allocationIt is the systematic process with the help of which computer program are being assigned with the memory or space. It is of three types such as first fit, best fit, and the worst fit. The first fit is the first hole that is very much big enough to allocate to the program. Moreover, the best fit is the smallest hole that is very much big enough to allocate to the program. Apart from this, the last fit is the worst fit that will have the largest hole that is very much big enough to allocate to the program.Memory ManagementCONCLUSIONFrom the whole analysis, it can be concluded that in the operating system of the computer Memory management has a vital role. This is due to the reason that it assures that all the memory of the computers should be stored in an effectual manner. Further, by having the idea about the main areas of Memory management, the programmer can make an effective decision in relation to the allocation as well as recycling of the memory in an efficient way. Further, by having good knowledge about the concepts of management,the programmer can assess a quick solution to the problem. Further, with the help of mentioned concepts, detailed knowledge about it can be gained.。

FAMAS Financial And Management Accounting System 金融管理会计系统FAMOS Fast Multi –Tasking Operating System 快速多任务操作系统FAMOS Floating –gate Avalanche injection MOS 浮动栅雪崩注入型金属氧化物半导体FAMS Forecasting and Modeling System 预测与建模系统FAMT Fully Automatic Machine Translation 全自动机器翻译FANET Federal Acquisition NETwork 联邦信息采集网FAP Facial Animation Parameters 面部表情参数〖MPEG〗FAP Failure Analysis Program 故障分析程序FAP File Allocation Problem 文件分配问题FAP Financial Analysis Program 财政分析程序FAP Floating –point Arithmetic Package 浮点运算软件包FAP Format And Protocol 格式与协议FAP FORTRAN Assembly Program Fortran语言的汇编程序FAPRS Federal Assistance Program Retrieval System 联邦辅助程序检索系统FAPS Financial Analysis and Planning System 金融分析与计划系统FaPS File and Print Service 文件和打印服务FAPUSMCEB Frequency Allocation Panel United States Military Communication Electronics Board 美国军事通信电子委员会频率分配小组FAQ Frequently Asked Questions 经常被问及的问题，常见问题解答〖因特网〗.faq 常问问题的文本文件格式〖后缀〗FAQS Fast Queuing System 快速排队系统FAR Facility Request 设备请求FAR Failure Analysis Report 故障分析报告FAR Fault Address Register 故障地址寄存器FAR File Address Register 文件地址寄存器FAR Function Analysis Report 功能分析报告.far 音乐文件格式〖后缀〗FARA Federal Acquisition Reform Act 联邦信息采集改革法案FARNET Federal Academic Research Network 联邦学术研究网FARNET Federation of American Research Networks 美国科研网络联盟FAS Federation of American Scientists 美国科学家联合会FAS Fiber Access System 光纤接入系统FAS Floating –point Arithmetic System 浮点运算系统FAS Frame Alignment Signal 帧对齐信号FASA Federal Acquisition Streamlining Act 联邦信息采集合理化法案FAST Facility for Automatic Sorting and Testing 自动分类测试设备FAST Fast Access Storage Technology 快速访问存储技术FAST Fingerprint Access and Searching Technique 指纹存取与搜索技术FAST Formula And Statement Translator 公式和语句翻译程序FAST Future Automatic Search Traveler 未来自动搜索旅行者技术〖数字护照〗FASTI Fast Access to System Technical Information 快速存取系统技术信息FASTNet Full Automated Switched Telecommunication Network 全自动切换式远程通信网FAT Fast Automatic Transfer 快速自动传送FAT File Allocation Table 文件分配表FAT Formula Assembler Translator 公式汇编程序翻译器FAT32 32 –bit File Allocation Table 32位文件分配表FATAL Fully Automatic Test Algebraic Language 全自动测试代数语言FATDL Frequency And Time Division Data Link 频率和时间分开的数据链路FAW Frame Alignment Word 帧对齐字FAX (Facsimile) 传真（设备，系统，传输）.fax 传真文件格式〖后缀〗FB Feedback 反馈FB File Block 文件块FB Fixed Block 固定块FB Flow Block 流程图FB Frame buffer 帧缓冲（器）FBA Facial and Body Animation 面部和身体动作译码器〖MPEG〗FBA Fanned Beam Antenna 扇形束天线FBA Fixed Block Architecture 固定块体系结构FBA Frame Bandwidth Allocation 帧带宽分配FBC File Buffer Count 文件缓冲区计数FBC File Buffered Channel 全缓冲通道FBD Flow Block Diagram 流程块图表FBD Function Block Diagram 功能块图表FBF FeedBack Filter 反馈滤波器FBFM FeedBack Frequency Modulation 反馈调频FBI Federal Bureau of Investigation 联邦调查局FBI Federation of British Industries 英国工业联合会FBI File Bus In 文件输入总线FBM Foreground and Background Monitor 前后台监控程序FBN FeedBack Network 反馈网络FBO File Bus Out 文件总线输出FBOE Frequency Band Of Emission 发射的频带FBRAM Frame Buffer RAM 帧缓冲器随机存取存储器FBT Facility Block Table 设备组表格FBTF Fiber Bundle Transfer Function 光纤束传送功能FC DOS的外部命令：比较两个文件的内容FC Failure Count 故障计数FC Failure Control 故障控制FC False Code 伪码FC Family Computer 任天堂家用机〖模拟器〗FC Feed Count 送纸计数FC Fiber Channel 光纤通道FC Fiber Connector 光纤连接器FC fingers crossed 十指交合〖网语〗FC Firefox Communications “火狐”通信设备公司（美国，出品网关设备）FC Flow Control 流程控制FC Folio Corp. “开卷”公司（美国，出品网络数据库出版工具）FC Font Change 字体改变FC Font Color 字体颜色FC Format Counter 格式计数器FC Frame Control 帧控制FC Frequency Changer 变频器FC Frequency Channel 频道FC Frequency Converter 变频器FC Fresh Copy 最新副本FC Full Client 全功能客户端〖服务器〗FC Functional Code 功能码.fc Harvard Graphics 2.0的拼写检查字典文件格式〖后缀〗FCA Fault Correction Array 故障纠正数组（惠普公司的）FCA File Cylinder Address 文件查找柱形区地址，文件同位标磁道组地址FCA Fixed Channel Allocation 固定通道分配FCA Frequency Conversion Accessory 频率变换辅助设备FCA Functional Configuration Audit 功能配置审查FC-AL Fiber Channel –Arbitrated Loop 光纤通道仲裁环FCB File Control Block 文件控制块FCB Forms Control Block 表单控制块FCB Forms Control Buffer 窗体控制缓冲器（区）FCB Function Control Block 功能控制块FCC Federal Communication Commission 联邦通信委员会（美国）FCC File Carbon Copy 文件复写副本FCC Flight Control Computer 飞行控制计算机FCC Forward Control Channel 前方控制通道FCCH Frequency Correction Channel 频率修正通道FCCN Federal Communication Commission Network 联邦通信委员会网络FCD Facsimile Coded Data 传真编码数据FCD Frequency Compression Demodulator 频率压缩解调器FCDR Failure Cause Data Report 故障原因数据报告FC-EL Fiber Channel Enhanced Loop 光纤通道增强环FCF Facilities Control Form 设备控制形式FCF Facsimile Control Field 传真控制字段FCF File CCW Flags 文件通道命令字标志FCF Frequency Compressive Feedback 频率压缩反馈FCFC First –Character Forms Control 首字符形体控制FCFS First Come First Served 先来先服务FCH File Count High 文件计数高位FCHM Fully Continuous Hidden Markov 完全不间断隐蔽型马尔可夫模型（用于嵌入软件的声音部件）FCI Frame Copied Indicator 帧拷贝指示器FCIF Full Common Intermediate Format 全通用中介格式FCIN Fast Carry Iterative Network 快速进位迭代网络FCL Feedback Control Loop 反馈控制环FCL Feeder Control Logic 馈线控制逻辑FCL File Count Low 文件计数低位FCL Format Control Language 格式控制语言FCLOSE File CLOSE 关闭文件FCM Fast Component Mounter 快速组件安装机FCM Fault Control Module 故障控制模块FCM File Compare Mask 文件比较掩码FCM Firmware Control Memory 固件控制存储器.fcm jlpak10的向前压缩二进制文件批处理文件格式〖后缀〗FCO Fault Control Office 故障控制室FCO Functional Check –Out 功能检查FCodes （Forth bytecodes）向前字节码FCP Federal Cataloging Program 联邦编目程序（美国）FCP File Control Panel 文件控制面板FCP File Control Procedure 文件控制过程FCP File Control Processor 文件控制处理器FCP File Control Program 文件控制程序FCP Firewall Control Protocol 防火墙控制协议FCP Four –Color Printing 四色打印FCP Frequency Comparison Pilot 频率对比向导FCP Fujitsu Computer Products Inc. 富士通计算机产品有限公司（日本，1935年从富士公司分出，出品硬盘、打印机、扫描仪、便携机等）FCP Function Control Package 操作程序包FCPGA Flip –Chip PGA 反转芯片针栅阵列，倒装塑针矩阵〖封装〗ECPU Flexible Central Processing Unit 软性中央处理单元FCS Facsimile Communications System 传真通信系统FCS Facsimile Control System 传真控制系统FCS Fast Circuit Switching 快速线路切换FCS Fiber Channel Standard 光纤通道标准FCS File Control Services 文件控制服务FCS File Control System 文件控制系统FCS First Customer Ship 第一艘顾客船（Sun公司的）FCS Frame Check Sequence 帧检查顺序FCS Frame Check Sum 帧检查概要FCS Frye Computer Systems Inc. 弗赖尔计算机系统公司（美国，出品网络管理设备）FCS Functional Check –Out Set 功能检验设置FCST Federal Council for Science and Technology 联邦科学技术委员会（美国）FCU File Control Unit 文件控制单元FCU Function Conversion Unit 功能转换单元FCW Format Control Word 格式控制字FD Feedback Decoding 反馈译码FD Fiber Duct 光纤管道FD File Definition 文件定义FD File Description 文件描述FD File Directory 文件目录FD Flexible Disk 软盘FD Floppy Disk 软盘FD Floppy Drive 软驱FD Frames Dropped 帧丢失数FD Frequency Diversity 频率差异FD Frequency Divider 分频器FD Frequency Doubler 倍频器FD Full Duplex 全双工FD Function Description 功能描述FD Function Device 功能设备.fd MS Fortran的说明文件格式〖后缀〗.fd DataFlex用于编译程序的域偏移量文件格式〖后缀〗FDA File Data Address 文件数据地址FDACS Floating Decimal Abstract Coding System 浮点十进制抽象编码系统FDB Field Descriptor Block 域描述符数据块FDB File Data Block 文件数据块FDB File Data Buffer 文件数据缓冲器（区）FDB Full Debug Build 完全调试生成〖测试〗FDB Functional Data Base 功能数据库FDBMS Federated Data Base Management System 联合数据库管理系统FDBS Federated distributed Data Base System 联合分布式数据库系统FDC Facsimile Data Converter 传真数据转换器FDC Field Data computer 野外数据计算机FDC Flexible Disk Controller 软盘控制器FDC Flight Director Computer 飞行定向器计算机FDC Floppy Disc Controller 软盘控制器FDC Fluid Digital Computer 射流数字计算机FDC Fractal Design Corp. 分形设计公司（美国，出品绘图软件）FDCS Functionally Distributed Computing System 功能分布式计算系统FDCT Factory Data Collection Terminal 工厂数据收集终端FDCT Forward Discrete Cosine Transform 前方离散余弦变换FDD Flexible Disc Drive 软式磁碟机，软盘驱动器FDD Floppy Disk Drive 软盘驱动器FDD Frequency Division Duplex 频率分开的双工操作，频分双工FDDI Fiber Distributed Data Interface 光纤分布式数据接口（局域网标准，100Mbps）FDDL Field Data Description Language 域数据描述语言FDDL File Data Description Language 文件数据描述语言FDDL Frequency Division Data Link 频率分开的数据链路，频分数据链路FDDQ Fair Dual Distributed Queuing 公平双分布式排队FDF Fiber Distribution Frame 光纤配线架FDFS File Descriptor File System 文件描述符文件系统（Sun公司的）FDHP Full Duplex Handshaking Protocol 全双工信号交换协议FDI Failure Detection and Identification 故障检测与识别FDI Feeder / Distribution Interface 馈线/ 配电接口FDIC Facsimile Data Interchange Continuance 传真数据交换接续设备FDISK Fixed DISK 固定磁盘FDL Facilities Data Link 设备数据链路FDL Feature Definition Language 特性定义语言FDL Figure Description Language 图形描述语言FDL File Definition Language 文件定义语言FDL Formatter Define Language 格式标识符定义语言FDL Forms Description Language 窗体描述语言FDM Frequency –Division Modulation 频率分开的调制，频分调制FDM Frequency –Division Multiplexing 频率分开多路复用，频分多工法FDMA Frequency Division Multiple Address 频率分开多路多址，频分多址FDME Frequency Division Multiplex Equipment 频率分开多路复用设备，频分多路复用设备FDMVC Frequency Division Multiplex V oice Communication 频率分开多路复用语音通信，频分多路语音通信FDP Fast Digital Processor 快速数字处理器FDP Facial Definition Parameters 面部定义参数〖MPEG〗FDP Fiber Distribution Point 光纤分布点FDP Field Developed Program 现场开发程序（IBM公司的）FDP File Definition Processor 文件定义处理器FDP Flight Data Processing 飞行数据处理FDP Form Description Program 表格描述程序FDP Fortran Debug Package Fortran调试程序包（施乐公司的）FDPC Federal Data Processing Center 联邦数据处理中心（美国）FDS Fast –Access Disc Subsystem 快速存取磁盘子系统FDS Fiber Distribution System 光纤分布系统FDS FielD Separator 字段分隔符FDS File Description Subsystem 文件描述子系统FDS File Description System 文件描述系统FDS Fixed Disk Storage 固定磁盘存储FDS Flexible Disk Storage 不定磁盘存储FDSL File Structure Definition Language 文件结构定义语言FDSP Full Duplex Service Phone 全双工免提电话FDT File Description Table 文件描述表FDT Formal Description Techniques 形式描述技术FDT Format Description Techniques 格式描述技术FDT Full Duplex Teletype 全双工电传打字机FDT Function Decision Table 功能决策表FDT Function Description Table 功能描述表FDTC Forward Data Traffic Channel 前方数据通信交往信道FDU Flexible Disc Drive Unit 软盘驱动器FDV Fault Defect Verification 故障缺陷验证FDVDI Fiber Distributed Video / V oice Data Interface 光纤分布式视频/ 语音数据接口.fdw F3设计与映射的格式文件格式〖后缀〗FDX Full DupleX 全双工FE Fast Ethernet 快速以太网FE Focus Error 聚焦误差〖光驱〗FE Format Effectors 格式控制字符FE Framing Error 成帧错误，图像定位错误FE Front End 前端（软件，装置等）FE Functional Entity 功能实体FEA Federal Energy Administration 联邦能源署（美国）FEA Field Effect Amplifier 场效应放大器FEAL Fast Encryption ALgorithm 快速加密算法.feb WordPerfect for Win用于Figure Editor的按钮棒形图文件格式〖后缀〗FEBE Far –End Bit Error 远端位错误FEBE Far –End –Block –Error 远端块错误FEC Feedforward Error Correction 前馈纠错FEC Floating Error Code 浮动错误码FEC Forward Error Coding 前方错误编码FEC Forward Error Control 前方错误控制FEC Forward Error Correction 正向纠错，向前纠错FEC Forward Error –Correcting Coding 正向纠错编码FEC Front –End Computer 前端计算机FECN Forward Explicit Congestion Notification 前方明显拥塞通知FECP Front End Communication Processor 前端通信处理机FECT Forward Error –Correction Technique 向前纠错技术FED Field Emission Display 场射显示器FED Forward Error Detection 前方错误检测FEDAC Forward Error Detection And Correction 正向检错和纠错FedCIRC Federal Computer Incident Response Capability 联邦计算机事件反应能力FEDI Financial Electronic Data Interchange 金融电子数据交换FEDINET FEDeral Information NETwork 联邦信息网FEDLINK FEDeral Library and Information NetworK 联邦图书情报网FED-STD FEDeral STanDard 联邦标准FEDWIRE FEDeral reserve WIRE 联邦备用线路FEE Failure Effects Evaluation 故障影响评估FEE Far –End Error 远端错误FEEL Fox Editor Enhancement Library 编辑器增强库（Visual FoxPro的）FEF File Error Flags register 文件错误标志（寄存器）FEFO First –End First –Out 先完先出，先结束先退出FEHM Fault / Error Handling Model 故障/ 错误处理模型FEI Fargo Electronics Inc. 法戈电子公司（美国，出品打印机）FEIS Financial Executive Information System 金融主管信息系统FEL Feedback Error Learning 反馈错误学习FEP Financial Evaluation Program 财务评估程序FEP Front End Processor 前端处理器FEP Flow Enforcement Parameter 流量执行参量FEP Flow Enhancing Protocol 流量增强协议FEP Front –End Processor 前端处理器FERF Far End Receive Failure 远端接收故障FERS Facility Error Recognition System 设备错误识别系统FES Field Effect Transistor 场效应晶体管FES Frequency Encoding Signal 频率编码信号FES Front –End Scanner 前端扫描器FESH Fast Ethernet Switching Hub 快速以太网交换式集线器（英特尔公司1996年推出）FET Field Effect Transistor 场效应晶体管FETS Field Effect Transistor Storage 场效应晶体管存储体FEXT Far –End Cross Talk 远端串音〖电话〗FF File Find 查找文件FF Final Fantasy 《最终幻想》，《太空战士》〖游戏名〗FF Fixed Frequency 固定频率FF Flip –Flop 触发器FF Form Feed 换页，送纸FF Full Figure 全图，全像.ff Agfa Compugraphics的字体轮廓描述文件格式〖后缀〗FFC Fixed –Form Coding 固定格式编码FFD Functional Flow Diagram 功能流程图FFF FeedForward Filter 前馈滤波器.fff defFax的传真文件格式〖后缀〗FFG Flip –Flop Group 触发器组FFG ForeFront Group “前沿”集团公司（美国，出品浏览器附件）FFGS Faust: the Seven Game of Soul 《浮士德：七个灵魂的游戏》〖游戏名〗FFH Fast Frequency Hopping 快速跳频FFM Fixed Format Message 固定格式报文FFN Full Function Node 全功能节点FFO Failure –Free Operation 无故障运行FFO Fixed Frequency Oscillator 固定频率振荡器FFR Freeze Frame Request 冻结帧请求FFS Formatted File System 格式化文件系统FFSK Fast Frequency –Shift Keying 快速移频键控FFSR FeedForward Signal Regeneration 前馈信号再生FFST First Failure Support Technology 首次故障支持技术FFT Fast Fourier Transform 快速傅里叶变换.fft DisplayWrite的Dca/FFT定型文本文本文件格式〖后缀〗FFTDCA Final Form Text Document Content Architecture 最终形式的文本文件内容体系结构FFTI Fast Fourier Transform Inverse 快速傅里叶反变换FFTS Fiber Feeder Transport System 光纤馈线传送系统FG Forward Gate 正向门（电路）FG Function Generator 功能发生器FGBM ForeGround and Background Monitor 前台与后台监视器FGC Fixed Gain Control 固定增益控制FGC Focusing Grating Coupler 聚焦光栅耦合器FGCS Fifth Generation Computing System 第五代计算系统FGIPC Federation of GovernmeGG Gate 栅极，门（电路），选通G Giga 千兆，吉G Graph 图形G Grid 网格，格栅G Grounding 接地.g APPLAUSE的数据图表文件格式〖后缀〗.g8 PicLab的半成品图形平面3文件格式〖后缀〗G.E.C. General Electric Company 通用电气公司（美国）G.TLD Generic Top –Level Domain 普通顶层域GA a Gigantic Adventure 《开心冒险家》〖游戏名〗ga Gabon 加蓬（域名）GA Gene Amdahl 吉恩·阿姆达尔（1922－1996 大型机之父）GA General Arrangement 常规排列GA Generic Algorithm 普通算法GA Global Address 共用地址，全局地址GaAs FETs Gallium Arsenide Field Effect Transistors 砷化镓场效应晶体管GA&CS Ground Acquisition and Command Station 地面接收和指令站〖航空〗GAC General Access Copy 通用存取副本GACT Graphic Analysis and Correlation Terminal 图像分析与校正终端GAHA Global Information Industry Association 全球信息产业协会联盟GAI Graphics Adapter Interface 图形适配器接口gais 盖世〖中文搜索引擎〗GAL Generalized Assembly Language 通用汇编语言GAL Generic Array Logic 通用阵列逻辑（电路）Galaxy “银河”系列显卡（生产商：AGI）GAM Graphics Access Method 图形存取法.gam GammaFax的传真文件格式〖后缀〗GAMA Graphics Assisted Management Application 图形辅助管理应用软件Game Blaster “游戏冲击波”系列显卡（生产商：Creative）GAN Generalized Activity Network 广义活动网络GAN Generating and Analyzing Network 生成与分析网络GANDALF General Alpha Numeric Direct Access Library Facility 通用甲级数字直接存取库设施GAP Gateway Access Protocol 网关存取协议GAP General Accounting Package 通用会计程序包GAP General Assembly Program 通用汇编程序GAP Graphics Application Program 图形应用程序GAPSS Graphical Analysis Procedures for System Simulation 用于系统仿真的图形分析规程GAPI Gateway Application Programming Interface 网关应用软件编程接口GAPT Graphical Automatically Programmed Tools 自动程控绘图工具GARP Group Address Registration Protocol 组地址注册协议GART Graphics Address Remapping Table 图形地址再映射表〖芯片组〗GAS Gateway Access Service 网关接入服务GAS Global Address Space 全局地址空间GAT General Application Template 通用程序模板GAT Generalized Algebraic Translator 通用代数翻译程序，广义代数翻译程序GAT Georgetown Automatic Translation 乔治敦自动翻译程序（美国乔治敦大学研制）GAT Global Atom Table 全局原子表〖编程〗GAT Graphic Arts Terminal 图形刻印艺术终端〖照排〗GAT Group Audio Terminal 群音频终端GA TD Graphic Analysis of Three –Dimensional Data 三维数据的图形分析GA TE General Purpose Automatic Test Equipment 通用自动测试设备Gateway 2000 网关两千〖厂标〗见：GIGA TT General Agreement on Tariffs and Trade 关税及贸易总协定，关贸总协GB Gain Bandwidth 增益带宽GB Game Boy 任天堂游戏小子〖模拟器〗GB GigaBit 千兆位，千兆比特GB GigaByte 吉字节，十亿（千兆）字节（1GB＝1，073，741，824 bytes =1,024MB）GB Gordon Bell 戈登·贝尔（1934－小型机之父）GB Graphic Background 图形背景gb Great Britain 大不列颠联合王国（域名）GB Group Box 组框〖编程〗GB (guo jia biao zhun) 国标（中国）GBEMS Golden Bridge Electronic Mail System 金桥电子邮件系统GBH Graphics Based Hypermedia 基于图形的超媒体GBL GarBLe 错乱，失真.gbl V AXTPU editor的通用定义文件格式〖后缀〗GBM Generalization –Based Memory 基于通用化的存储器GBMP General Bench Mark Program 通用基准程序GBOF General Bill –of –Forms 通用帐表GBNET Gold Bridge interNET 金桥网（即中国国家公用经济信息网）GBP Gain Bandwidth Product 增益带宽乘积Gbps Gigabits / Second 每秒千兆位GBR Global Base Register 共用基准寄存器GBS General Business System 通用商业系统GBT Group on Basic Telecommunications 基础电信分组GBTS General Banking Terminal System 通用银行终端系统GC Genicom Corp. 基因通信公司（美国，出品打印机，德州仪器公司属下）GC Global Control 全球网控制GC Graph Control 统计图控件〖编程〗GC Graphics Context 图形环境（Sun公司的）GC Group Command 组命令.gc1 V AXTPU editor的源码文件格式〖后缀〗.gc3 Golden Common Lisp 3.1的源码文件格式〖后缀〗GC Guidance Computer 导航计算机GCA Gain Control Amplifier 增益控制放大器GCA Ground –Controller Approach 地面控制进场着陆系统GCAP Generalized Circuit Analysis Program 通用电路分析程序GCC General Conference Control 通用会议控制技术GCC Graphic Character Composition 图形字符合成GCC Guidance Checkout Computer 制导校验计算机GCCA Graphic Communications Computer Association 图形通信计算机协会GCCS Global Command Control System 共用指挥控制系统GCD Global Common Directory 综合公用目录.gcd 图形文件格式〖后缀〗GCE Graphics Control Extension 图形控制扩展GCE Ground Checkout Equipment 地面检验设备GCE Ground Common Equipment 地面公用设备GCE Ground Communication Equipment 地面通信设备GCE Ground Communication Facility 地面通信设施GCE Ground Control Equipment 地面控制设备GCH Giga Characters 吉字符，千兆字符GCHQ Government Communications HeadQuarters 政府通信总部（英国）GCI Garbage Collection Interval 垃圾收集间隔GCI General Command Interface 通用命令接口GCI General Communications Interface 通用通信接口GCI Ground – Controlled Interception 地面控制拦截GCM General Circulation Model 常规循环模型GCM Generic Call Monitor 一般呼叫监视器GCN Generalized Connection Network 通用连接网络GCOE Ground Controlled Operational Equipment 地面控制的操作设备〖飞行〗GCP Grand challenge Problems 重大挑战性问题GCPS GigaCycles Per Second 每秒千兆赫GCP Ground Control Point 地面控制点GCR Ghost Cancellation Reference Signal 虚像取消参照信号GCR Ground Controlled Radar 地面控制雷达GCR Group Coded Recording 成组编码记录GCRA Generic Cell Rate Algorithm 普通单元速率算法GCS Gate Controlled Switch 栅控开关GCS General Computer System, Inc. 通用计算机系统公司GCS Global Control System 共用控制系统GCS Graphics Compatibility System 图形兼容性系统GCS Ground Communication System 地面通信系统GCS Group Control Subsystem 群控子系统GCSS (Global Command and Control System and the Global Combat Support System) 全球指挥控制系统与全球战斗支援系统GCSS Global Communication Satellite System 全球通信卫星系统GCSS-AF Global Combat Support System – Air Force 空军全球战斗支援系统GCT Graphics Communications Terminal 图形通信终端GCT Greenwich Civil Time 格林威治民用时GCT Guidance Computer Test 指导计算机测试GCTS Ground Communication Tracking System 地面通信跟踪系统GCTTech 汶鸿主板〖品牌〗GD Gate Driver 门驱动器GD Global Data 全局数据GD good day 白天好〖网语〗GD GrounD 接地，地线GD Group Delay 组延时gd Grenada 格林纳达（域名）GDA Global Data Administrator 共用数据管理程序GDA Global Data Area 共用数据区域GDAS General Data Analysis and Simulation 一般数据分析和模拟GDAS Ground Data Acquisition System 地面数据采集系统GDB Global Data Base 共用数据库GDBMS Generalized Data Base Management System 综合数据库管理系统GDBMS Global Data Base Management System 共用数据库管理系统GDBS Global Data Base System 共用数据库系统，全球数据库系统GDC General – purpose Digital Computer 通用数字计算机GDC Graphics Display Controller 图形显示控制器GDCI General Data Communications Interface 一般数据通信接口GDD Group Delay Dispersion 组延时色散GDDL Graphical Data Definition Language 图形数据定义语言GDF General Data File 一般数据文件GDF Graphics Data File 图形数据文件GDF Group Distribution Frame 用户组配线架.GDF GEOS的字典文件格式〖后缀〗GDHP Globalized Dual Heuristic Programming 全局化双启发式编程GDHS Ground Data Handling System 地面数据处理系统GDI General Database Interface 通用数据库接口GDI Graphic Device Interface 图形设备接口GDI Graphical Direct Interface 图形直接接口GDI Graphical Driver Interface 图形驱动程序接口GDIP GDI Printer 基于主机的打印机GDL Global Data Link 全球数据链接，环球数据线路GDL Graphic Display Library 图形显示库GDM Generalized Directive Model 广义指令模型GDM Global Data Manager 共用数据管理器，全局数据管理程序GDM Graphical Desktop Management 图形桌面管理GDMI Generic Definition of Management Information 管理信息的一般定义GDMO Guidelines for the Definition of Managed Objects 管理对象定义准则GDMS Generalized Data (base) Management System 广义数据（库）管理系统GDN Global Directory Navigator 共用目录引导器GDN Government Data Network 政府数据网（英国）GDNS Global Domain Name Server 共用域名服务器GDO Grid – Dip – Oscillator 栅陷振荡器GDOS Generalized Disk Operating System 通用磁盘操作系统GDOS Graphic Disk Operating System 图形磁盘操作系统GDP Generalized Data Base Processor 通用数据库处理器GDP Goal Directed Programming 目标引导的程序设计GDPS Generalized Disk Programming System 通用磁盘编程系统GDPS Global Data Processing System 共用数据处理系统GDRAM Synchronous Graphic Dynamic Random Access Memory 同步图形动态随机存取存储器GDS Generalized Data base (Sub)System 通用数据库（子）系统GDS Generalized Data Structure 通用数据结构GDS Global Data Schema 共用数据模式GDS Global Data – processing System 共用数据处理系统GDS Global Digital high Speed road 全球数字高速公路GDS Global Directory Service 共用目录服务GDS Global Directory System 共用数据系统GDS Graphic Data System 图形数据系统GDS Graphic Design System 图形设计系统GDS Graphic Display System 图形显示系统GDS / HA Graphical Design Specification for Hospital Administration 医院管理图形设计规范，GDS / HA语言GDSDF Generalized Data Structure Definition Facility 广义数据结构定义设备GDSS Global Decision Support System 共用决策支持系统GDSS Group Decision Support System 群体决策支持系统GDT Gate Delay Time 门延迟时间GDT Global Descriptor Table 共用描述符表GDU Graphic Display Unit 图形显示器GE General – graphic Editor 通用图形编辑程序GE General Electric Co. 通用电气公司（美国）ge Georgia 格鲁吉亚（域名）GE Gigabits Ethernet 十亿比特以太网，千兆位以太网GE Graphic Escape 图形换码，图形转义符GE Greater than or Equal to 大于或等于（Fortran 用语）GE Ground Equipment 地面设备GEA Gigabit Ethernet Alliance 千兆位以太网联盟GEA Graph Extended Algol 图形扩展Algol语言GEAM Generic Engineering Analysis Model 普通工程分析模型GEC General Electric Corporation 通用电气公司GECOM GEneral COMpiler 通用编译程序GECOS GEneral Comprehensive Operating System 通用综合操作系统.ged Arts & Letters的编辑器本地文件格式〖后缀〗GEDAN GEneral Data ANalyzer 通用数据分析程序GEEC Gigabit Ethernet Educational Council 千兆位以太网教育委员会GEIS GE Information Service 通用电气公司信息服务GEIS General Electronic Information Service 一般电子信息服务GEL General Emulation Language 同意仿真语言GEM Global Enterprise Manager 企业网全局管理器.gem GEM和V entura Publisher的矢量图形文件格式〖后缀〗GEMMS Global Enterprise Manufacturing Management System 企业制造全局管理系统GEMS General Epitaxial Monolithic Silicon 普通单晶硅片GEMS Global Enterprise Management of Storage 全局性企业存储管理GEN Gigabit Ethernet Networking 千兆位以太网联网GEN Global Education Network 全球教育网（中国分部：启迪咨询培训有限公司）GEN Global Enterprise Network 全球企业网GEN Global European Network 欧洲共用网，全欧网.gen dBase Application Generator的编译模板文件格式〖后缀〗.gen Ventura Publisher生成的文本文件格式〖后缀〗Genesis “创世纪”系列显卡（生产商：耕宇）GENIE General Electric Network for Information Exchange 通用电器公司的信息交换网GENTEC General Telephone & Electronic Co. 通用电话与电子公司（美国）GENUSC Global Enterprise Network User Super Conference 全球企业网用户高峰会议GEO GEOstationary 与地球同步的GeoCities “地球村”（网站名，1999.1被雅虎并购）GEOS Geodetic Earth Orbiting Satellite 大地测量地球轨道卫星GEOS Geosynchronous Earth Orbit Satellite 地球轨道同步卫星GEOS Graphical Environment Operating System 图形环境操作系统GEP Grolier Electronic Publishing 格罗利尔电子出版公司（法国，专出综合知识类光盘）GEROS GEneral Routine Optimization System 通用例程最佳化系统GERT Graphical Evaluation and Review Technique 图形鉴定与检测技术GERTS GEneral Remote Terminal Supervisor 通用远程终端管理程序GERTS GEneral Remote Terminal System 通用远程终端系统GERTS GEneral Remote Transmission Supervisor 通用远程传输管理程序GES Gateway Exchange Switches 网关交换机开关GES General(ized) Edit System 通用编辑系统GES Global Event Services 全局事件服务GES Ground Earth Station 地面地球站GES Ground Electronic System 地面电子系统GESAL General Electric Symbolic Assembly Language 通用电器符号汇编语言GESAL GEneral Symbolic Assembly Language 通用符号汇编语言GESC (Government Electronic Data Processing Standards Committee) 政府电子数据处理标准委员会（加拿大）GESPL Generalized Edit System Programming Language 通用编辑系统编程语言GEYP Global Electronic Yellow Page 全球电子黄页〖电话号码簿〗gf French Guiana 法属圭亚那（域名）GF Glossy Film 光面胶片〖打印机介质〗GF Gradient Fill 渐变色填充〖打印机〗GFA General Frame Allocation 通用帧分配.gfb 由GIFBLAST生成的压缩GIF图像文件格式〖后缀〗GFC General Flow Chart 总流程图GFC General Flow Control 总流量控制GFF Graphics File Formats 图形文件格式GFI General Format Identifier 通用格式标识符GFLOPS Giga FLoating –point Operations Per Second 每秒千兆浮点运算次数GFP Global Functional Plane 共用作用面GFS Grandfather – Father – Son 祖辈－父辈－子辈调度法GFSK Gauss Frequency Shift Key 高斯频移键GFT Generalized Fault Table 广义故障表.gft NeoPaint的字体文件格式〖后缀〗GG Global Group 全局组〖网络〗GG Go ahead Got it “勇往直前，夺取目标”（“勇往直前”软件公司1998年出品的网页浏览加速器）〖软件名〗GG good game 上等游戏〖网语〗GGC Ground Guidance Computer 地面制导计算机GGID Global Graphic Character Identifier 共用图形字符标识符GGP Gateway – to – Gateway Protocol 网关至网关协议gh Ghana 加纳（域名）GHz Gig Hertz 千兆赫GI Gateway 2000 Inc. 网关2000公司（美国，出品笔记本电脑等）GI General Information 通用信息gi Gibraltar 直布罗陀（域名）GI Group Identification 群组识别GI Group Identifier 群组识别符GI Group Interface 组接口.gib Graph-in-the-Box的图表文件格式〖后缀〗GIBN Global Interoperability for Broadband Network 宽带网全球互用性GIC General Input / Output Channel 通用输入/ 输出通道GIC General Instrument Corporation 通用仪器公司（美国）GID Gateway ID 网关标识符GID General IDentifier 通用标识符GID Group ID (Identifier) 组标识符GID Group IDentification number 组识别号码GIDEP Government Industry Data Exchange Program 政府工业数据交换程序GIF Graphics Interchange Format 图形交换格式（美国计算机服务公司1987年开发）.gif 可以存储动画的图像格式，美国计算机服务公司的图像文件图形交换格式〖后缀〗GIG Giga Information Group 千兆信息组GigaByte 技嘉科技股份有限公司（台湾，出品主板）GIGO Garbage In, Garbage Out 垃圾进来，垃圾出去（输入的是错误数据，输出的也是错误数据），无用输入，无用输出GII Geospatial Information Infrastructure 地球空间信息基础设施GII Global Information Infrastructure 全球信息基础设施（1994年美国提出）GIIC Global Information Infrastructure Committee 全球信息基础设施委员会GII-IS Global Information Infrastructure and the Information Society 全球信息基础设施和信息社会GIIPT Geospatial Information Integrated Product Team 地球空间信息综合产品组GIL General purpose Interactive programming Language 通用交互式编程语言GILC Graphical Input Language Computer 图形输入语言计算机GILC Graphical Input Logic Computer 图形输入逻辑计算机GILS。

lie 说谎lie confession 谎供lie detector 测谎器lie scale 测谎量表liepmann s apraxia 利普曼氏运用不能liepmann s effect 利普曼效应life 生命life age 生命年龄life change units 生活变化单位life curve 生命曲线life cycle 生命周期life cycle analysis 生命周期分析life cycle of commodities 商品生命周期life cycle theory of leadership 领导的生命周期理论life event scale 生活事件量表life expectancy 预期寿命life experience 生活经验life force 生命力life goal 生活目标life instinct 生存本能life jacket 救生衣life line 生命线life position 生命地位life record 生活史life rehearsal 生活演练life sciences 生命科学life skill counseling 生活技能咨询life space 生活空间life space continuity 生活空间连续性life space interview 生活场面面谈life span 寿命life stress 生活应激life style disease 生活方式疾病life table 生命表lifetime education 生涯教育lifetime employment system 终身雇用制lifetime personality 终身性格life span development 毕生发展life span developmental psychology 生涯发展心理学life span perspective 毕生发展观life support system 生命维持系统life threatening 危害生命life world 生活世界light 光light activated 光敏感的light adaptation 光适应light comparison technique 光比较法light compass movement 光罗盘运动light constancy 光恒常性light difference 光差light distribution of illuminator 照明器光线分布light dread 恐光症light exposure 曝光light filter 滤光器light halo 光晕light induction 光诱导light intensity 光强度light minimum 最低度光觉light pen 光笔light proof 不透光的light reaction 光反应light reflex 光反射light sensation 光觉light sense 光觉light sensitive 感光的light sensitive 光敏的light sensitivity 感光性light sensitivity 光敏度light signal display 信号灯显示light source 光源light vision 明视觉lighting 照明lighting effectiveness factor 照明有效系数lightmeter 光度计lightness 光度lightness contrast 明度对比light dark adaptation 明暗适应light dark ratio 明暗比light induction 光诱导likable 可爱的likableness 可爱like 爱好like 相似likelihood 似然性likelihood analysis 似然分析likelihood ratio 似然比likelihood ratio criterion 似然性比率评准likeness 类似likert management system 利开特管理系统likert method 利开特法likert procedure 利开特程序likert scale 利开特式量表likert scaling 利氏量表法likert technique 利开特法likert type attitude scale 利式态度量表like dislike 爱好厌恶like indifferent dislike 喜欢无所谓厌恶liking 爱好lilliputian hallucination 渺小幻觉limbic lobe 边缘叶limbic system 边缘系统limbus 缘limbus boundary method 角膜缘部测定法limbus of corneae 角膜缘limb kinetic apraxia 肢体运动性运用不能limen 阈限limen of twoness 两点阈limes 限量limes reacting dose 反应限量liminal 阈限的liminal stimulus 阈限刺激limit 极限limit 限度limit analysis 极限分析limit checks 极限检验limit distribution 极限分布limit method 极限法limit of error 误差界限limit of interval 区间限limit of perception 感觉限度limit of the error of sampling 抽样误差限limit point 极限点limit process 极限法limit sample 极限样本limit superior 上极限limit value 极限值limitation 限制limited capacity 有限容量limited information 有限资料limited prediction 有限推测limiting 极限limiting character 极限特性limiting chi square distribution 极限x2分布limiting distribution 极限分布limiting form 极限形式limiting point 极限点limiting surface 界面limiting value 极限值limits 极限limits of trustworthiness 可靠性限度limosis 善饥症limotherapy 饥饿疗法lincoln oseretsky motor development scale 林奥二氏肌动发展量表line 线line chart 线形图line diagram 线形图line graph 线图line in education 教育路线line length coding 线长编码line of business 行业line of direction 方向线line of regard 注视线line organization 直系组织line plotting 画线line production 流水作业line relationship 直线关系line segment 线段lineage 世系linear 线性linear additive model 线性递加模式linear analysis 线性分析linear approximation 线性近似linear causal model 线性因果模型linear correlation 线性相关linear discrimination function 线性辨别函数linear equating 直线等化linear equation 线性方程linear function 线性函数linear inference 线性推演linear interpolation 线性内推法linear maze 直线迷津linear model 线性模式linear operator model 线性演算器模式linear order 直线序列linear order of genes 基因直线排列linear perspective 直线透视linear program 直线式程序linear regression 线性回归linear regression analysis 线性回归分析性归分析linear regression equation 直线回归方程式linear regression in z ×c table线性回归z×c 表linear regression method 线性回归法linear relation 线性关系linear relationship 线性关系linear syllogism 线性三段论linear transformation 直线转换linear trend 直线趋向linear type 直线型linearity 直线性linearity condition 线性条件linearity error 线性误差linearly independent vector 线性独立向量lingual nerve 舌咽神经linguistic ability 语言能力linguistic analysis 语言分析linguistic approach 语言教读法linguistic behavior 语言行为linguistic capacity 语言能力linguistic code 语言编码linguistic competence 语言能力linguistic context 语言的前后关系linguistic expression 语言表达式linguistic form 语言形式linguistic information 语言信息linguistic kinesic method 语言运动法linguistic organization 语言结构linguistic performance 语言行为linguistic psychology 语言心理学linguistic relativism 语言相对论linguistic relativity 语言相关性linguistic relativity hypothesis 语言相对假说linguistic relativity principle 语言相对原则linguistic skill 语言技能linguistic structure 语言结构linguistic symbol 语言符号linguistic unit 语言单元linguistic universal 语言共通性linguistics 语言学link 环link 联结link analysis 链分析link trainer 环状训练舱link up 连接linkage 联系linked character 关联特征linking rule 连接规则linophobia 绳索恐怖症lip erotism 唇欲lip key 唇键lip language 唇话liparodyspnea 肥胖性呼吸困难lipase 酯酶lipid 脂类lipomatosis 脂肪过多症lipophrenia 失神lipostatic theory 恒脂论lipothymia 昏厥lipps figure 利普斯图形lipreading 读唇法lips 唇lip reading 唇读liquid 液体liquid conservation 液体守恒liquid crystal 液晶liquid crystal display 液晶显示liquidation of memory 记忆同化liquidity 流动性lisp 口齿不清lissauer s paralysis 卒中型麻痹性痴呆list 清单listen 听listening 听力listening comprehension 听懂listening gear 听音器listening with the third ear 第三只耳朵listing technique 列举法listing s law 利斯廷定律literacy 识字literacy test 识字测验literal 文字的literal alexia 字性失读literal notation 文字记号literal paraphasia 字性错语literal perception 精密知觉literary and artistic appreciation 文艺欣赏literary and artistic creation 文艺创作literary language 文学语言literary psychology 文艺心理学literary artistic imagination 文艺想象literature 文献literature 文学literature review 文献评论lithium 锂盐lithium carbonate 碳酸锂盐lithium therapy 锂疗litigation psychology 诉讼心理学litigious delusion 诉讼妄想little s disease 痉挛性两侧瘫little s disease 李特耳氏病lived experience 生活体验livelihood 生活lively type 活泼型livierato s sign 利韦拉托症living clock 生物钟living condition 生活条件living environment 生活环境living form 生活型living goods 生活用品living level 生活水平living space 生活空间living standard 生活标准living substance 生活物质lloyd morgan s canon 摩根法则lmx theory 领导者成员交换理论lness 性善恶混论load 负荷load stress 负荷应激loading 负荷量loading routine 输入程序lobes of cerebrum 大脑叶lobotomized personality 额叶切除人格lobotomy 额叶切除术lobstein s disease ganglion 洛布斯坦神经节lobus centralis 小脑中叶lobus occipitalis 枕叶lobus olfactorius 嗅叶lobus opticus 视叶lobus parietalis 顶叶local 局部local anaphylaxis 局部过敏local circuit 局部路local control 局部控制local convergence 局部收敛local disturbance 局部障碍local effect 局部效应local epilepsy 局部性癫痫local excitatory 局部兴奋态local fatigue 局部疲劳local habitats 本土生境local independence 局地独立local lighting 局部照明local maximum 局部极大local minimum 局部极小local norm 地区常模local optimum 局部最优local pattern 局部模式local phenomenon 局部现象local population 地域人口local reaction 局部反应local reflex 局部反射local response 局部反应local restriction 局部制约local sign 部位记号local stability 局部稳定性local terminal 本机终端local vibration 局部振动locality of animal behavior 动物地域性行为localization 定位localization of function 机能定位localization of function in cortex 大脑机能定位localization of genes 基因定位localization of psychological function 心理机能定位localization theory 机能定位论localized amnesia 局部失忆症localized disturbance 局部失调localized general lighting 分区一般照明localized learning 局部性学习localized transduction 局部性传导location 位置location chart 位置图表location constancy 位置常性location of controls 控制器位置location of displays 显示器位置locational space 位置空间lock and key theory 锁与匙论locomotion 位置移动locomotor 运动器官的locomotor ataxia 运动共济失调locomotor genital stage 运动性欲期locus 地点locus 轨迹locus of control 控制点log 对数log normal distribution 对数常态分布logagnosia 失语症logagraphia 失写症logamnesia 记言不能logaphasia 表达性失语症logaphasia 运动性言语不能logarithmic characteristic 对数特性logarithmic computation 对数计算logarithmic coordinates 对数坐标logarithmic mean 对数平均数logarithmic property 对数性质logarithmic table 对数表logasthenia 言语理解困难logic 逻辑logic behavior 逻辑行为logic decision making 逻辑决策logic equation 逻辑方程logic judgment 逻辑判断logic learning 推理式学习logic memory 逻辑记忆logic model 逻辑模式logic network 逻辑网络logic of faith 信念逻辑logic of language 语言逻辑logic of modality 模态逻辑logic of natural language 自然语言逻辑logic of proposition 命题逻辑logic of question 问句逻辑logic of relation 关系逻辑logic of science 科学逻辑logic rule 逻辑规则logic theorist 逻辑理论家logic theory 逻辑论logical abstraction 逻辑抽象logical algebra 逻辑代数logical analysis 逻辑分析logical argumentation 逻辑论证logical axiom 逻辑公理logical calculus 逻辑演算logical category 逻辑范畴logical checking 逻辑检验logical combination 逻辑组合logical comparison 逻辑比较logical condition 逻辑条件logical deduction 逻辑演绎logical deduction by reasoning 逻辑推理logical derivation 逻辑推导logical empiricism 逻辑经验主义logical entailment 逻辑蕴涵logical equation 逻辑方程logical error 逻辑错误logical expression 逻辑表达logical formula 逻辑式logical grammar 逻辑语法logical ground 逻辑的根据logical idealism 逻辑唯心论logical identity 逻辑的同一logical inclusion 逻辑的包含logical interdependence 逻辑的相互依赖logical judgment 逻辑判断logical knowledge 逻辑认识logical language 逻辑语言logical law 逻辑定律logical memory 逻辑记忆logical method 逻辑方法logical multiplication 逻辑的繁衍logical necessity 逻辑的必然性logical nets 逻辑网格logical neuron 逻辑神经元logical operations 逻辑运算logical order 逻辑程序logical positivism 逻辑实证论logical possibility 逻辑可能性logical priority 逻辑的先在性logical proof 逻辑证明logical proposition 逻辑命题logical reasoning 逻辑推理logical record 逻辑记号logical rigor 逻辑的严密性logical simulation 逻辑模拟logical structure 逻辑结构logical sum 逻辑和logical symbol 逻辑符号logical syntax 逻辑句法logical system 逻辑系统logical term 逻辑术语logical theory 逻辑理论logical thinking 逻辑思维logical type 逻辑型logical validity 逻辑效度logical variable 逻辑变量logicality 逻辑性logically compatible 逻辑相容的logically proper name 逻辑专名logicosemantic analysis 逻辑语义分析logic in use 应用逻辑logistic discrimination 逻辑辨别logistic method 逻辑函数法logistic transformation 逻辑变换logistics system 符号逻辑体系logoclonia 言语痉挛logocophosia 听性失语logodiarrhea 多言症logogriph 字谜logoklony 痉语症logokophosia 听性失语logokophosis 词聋logomachy 字谜游戏logomania 多语症logoneurosis 言语神经机能症logopathy 言语障碍logopedia 言语矫正法logopedics 言语矫正法logophasia 口吃logophobia 谈话恐怖症logoplegia 发音器官麻痹logorrhea 多语癖logos 理性logospasm 痉语症logotherapy 言语疗法log linear models 对数线性模型log linear smoothing model 对数线性平滑模型loneliness 孤独lonely crowd 孤独人群loner 孤独的人long 长的long distance hearing 远距离听觉long distance vision 远距离视觉longevity 长寿longevous 长命的longing 渴望longish 稍长的longitudinal 纵向的longitudinal design 纵向设计longitudinal fissure 大脑纵裂longitudinal method 纵向法longitudinal research 纵向研究longitudinal study 纵向研究longitudinal survey 纵向调查longitudinal wave 纵波longwall method 长壁法long circuit appeal 长期招徕long hot summer effect 长夏效应long range planning 长期经营计划long sightedness 远视long term effect 长期效应long term memory 长时记忆long term store 长期贮存lonizing radiation 放射线looking glass self 镜映自我look and say 看和说look glass self 镜映自我looming 庞视loop 环loose construct 松散性结构loosening 放松loosening of associations 联想散漫loquacity 多语争辩癖lordosis 脊柱前曲lorge thorndike intelligence test 洛桑二氏智力测验loss 失落loss boundaries of ego 自我界限消失loss of consciousness 意识丧失lost generation 迷惘的一代lost letter technique 丢信方法lost time injury 失时伤害loud reading 朗读loud speaker 扬声器loudness 响度loudness compensation 响度补偿loudness contour 等响曲线loudness discrimination 响度辨别loudness level 响度级loudness perception 响度知觉love child 私生子love needs 爱的需要lovelace 色鬼love object 恋爱对象low altitude flight 低空飞行low birth weight infant 出生低体重儿low pressure 低压low temperature 低温lowenfeld mosaic test 洛温菲尔德拼镶测验lower absolute threshold 下绝对阈限lower difference threshold 下差别阈lower limit 下限lower limit value 下限值lower management 现场管理lower mental process 低级心理过程lower nervous activity 低级神经活动lower orders 下层社会lower pressure environment 低压环境lower pressure environment tank 低压舱lower quartile 下四分位数lower sensation 低级感觉lower threshold 下辨别阈lower value 下限值lowering trend of criminal age 犯罪低龄化lowerleg foot length 足小腿高lower order needs 较低层次需要lowest audible tone 最低可听音lowlife 下层社会的人low grade defective 轻度身心缺陷loxophthalmus 斜视loyalty 忠诚lpc 最差同事lpc questionnaire 最难共事者问卷lps 利侧表lq 下四分位值lr 反应限量lrcs 语言认知结构lsd 麦角酸二乙基酰胺lt 逻辑理论家lth 促黄体分泌激素ltm 长时记忆长期记忆ltt 潜在特质理论lucifugal 避光的lucotherapy 光线疗法ludd franklin theory 鲁德弗兰克林说lullaby 催眠曲lumbar spinal cord 腰背lumen 流明lumen per square meter 流明平方米lumenmeter 流明计lumen second 流明·秒luminance 亮度luminance balance 亮度平衡luminance coding 亮度编码luminance contrast 亮度对比luminance difference 亮度差异luminance factor 亮度因素luminance meter 亮度计luminance non uniformity 亮度非均匀性luminance non uniformity 亮度非均匀性亮度非均匀性luminance ratio 亮度比率luminance threshold 亮度阈限luminescence 发光luminophor 发光体luminosity 亮度luminosity body 发光体luminosity coefficient 照度系数luminosity function 亮度函数luminous 发光的luminous body 发光体luminous efficiency 光效率luminous efficiency curve 光效率曲线luminous emittance 光发散度luminous environment 发光环境luminous flux 光通量luminous intensity 光强luminous reflectance 光反射率lump sum separation allowance system 退职金制度lumsden s center 呼吸调节中枢lunar periodicity 月周期性lunatic 精神病患者lung 肺lung volume and capacity 肺活量luria nebraska neuropsychological battery 鲁内神经心理成套测验luridine 胆碱lust 色欲lust of pain 疼痛色情luster 光泽lustrous 有光泽的lutein 黄体素luteinizing hormone 黄体生长激素luteinizing hormone releasing factor 促黄体生成素释放因子luteinizing hormone releasing hormone 黄体生成素释放激素luteotrophic 促黄体的luteotrophic hormone 促黄体分泌激素lux 勒克斯luxury 奢侈lycanthropy 变狼狂lygophilia 暗室癖lygophilia 嗜室症lying 说谎lying posture 躺姿lying with face downward 面向下躺lying with face upward 面向上躺lympha 淋巴lymphatic temperament 粘液质lynching 私刑lypemania 悲伤狂lypemania 沮丧癖lypothymia 忧郁症lysergic acid 麦角酸lysergic acid diethylamine 麦角酸二乙基酰胺lysine 赖氨酸lysine decarboxylase 赖氨酸脱羧酶lysine racemase 赖氨酸消旋酶lyssophobia 狂犬病恐怖症lm最低度光觉lva左视敏度ldopa 左旋多巴lid 喜欢无所谓厌恶。

The thesis is a review paper that gives an introduction to the new mobile platform. Android as well as a comparative evaluation with regard to other mobile operating systems.The key topic of this thesis is the categorization of Android.Therefore it first gives a historical introduction to cell phones and mobile operating systems.Then it describes the main features of Android for a better understanding of this platform.In the following theoretical part Android will be compared to the mobile operating systems Symbian OS and Windows Mobile. Features and criteria defined in this part will be considered and included in the comparison of these systems.The practical part contains a comparison of the Software Development Kits (SDK) from Android and Symbian OS. In this context a simple application implementation on both systems is realized tosupport this comparison.Finally an outlook and a conclusion complete this elaboration.这是一篇介绍新的手机系统的论文，也将Android和其他手机操作系统进行了比较评价。

•Introduction to Computer Systems•TA: He Lin•12.28.2010•UNIT 1 Computer SystemsMultiple-Choice Quiz 11.Which of the following is (are) true aboutcomputers?I. They accept input.II. They store data.III. They produce output.(a)II and III only(b)II only(c)I and III only(d)I, II, and III2.Which of the following can supply input toa computer?以下哪一个可以向计算机提供输入？I. A person 人II. The environment环境III. Another computer 另一台计算机(a) I and II only(b) I, II, and III(c) III only(d) I only3.A computer processes data in a device called the一台计算机在一个设备上处理数据，那么这个设备被称为：(a) Server服务器(b) URL (Uniform Resource Locator）统一资源定址器(c) CPU（central processing unit）中央处理器(d) device driver(设备驱动器)4. A computer file is a named collection of data that exists on which of the following?数据集文件存在于以下哪个地方？I. Optical disk (CD or DVD) 光盘II. Floppy disk 软盘III. Hard disk 硬盘(a)I, II, and III(b)II and III only(c)III only(d)I onlyputers that operate in essentially the same way are said to be计算机操作在本质上同样又被称作(a)Integrated一体的(b)Compatible兼容的(c)Compound混合的(d)user-friendly 友好的Multiple-Choice Quiz 21.Which of the following is (are) true regarding theuse of punched cards in computers?关于计算机上穿孔卡片的用途，以下那一项是正确的？I. Punched cards use a technique that was originallyused in Jacquard looms.穿孔卡片使用的一种技术最初用于提花纺织机上II. Punched cards can be used to store programinstructions, but not data.穿孔卡片能够被用于存储程序指令，而不能是数据(a)I and II(b)None(c)II only(d)I only2.Which of the following is (are) true regarding the application of computers in the business field?对于计算机在商业领域的应用，以下哪个是正确的？I. Computers can be used in supply chain management both for tracking the supply of raw materials as well as the supply of finished products.计算机可用于跟踪原材料的供应和成品的供应的供应链管理。

10-bit character frame10位字符帧20mA interface20mA接口3964®driver3964®驱动程序4-wire transducer4线制传感器absolute address绝对地址absolute addressing绝对寻址absolute coding绝对编码absolute encoder adjustment绝对编码器调整absolute incremental mode绝对增量模式absolute value sensor绝对编码器absolute zero shift绝对零漂移Accept button“接受”按钮access protection存取保护accumulator累加器accumulator instruction累加器指令acknowledged已确认acknowledgement确认acknowledgement area of a dialog box对话框确认区acknowledgement group确认组acknowledgement key确认键acknowledgement tag确认变量acknowledgement theory确认理论acknowledgement time确认时间ackowledgement bit确认位acquisition cycle采集周期action block动作块action monitoring动作监视action time动作时间activate激活activate machine data激活机器数据activate time-of-day interrupt激活时钟中断active...活动...active receiver主动接收器active redundancy活动冗余active star coupler活动星型耦合器actual parameter实际参数actual position实际位置actual value实际值actual value display实际值显示actual value monitoring实际值监视actuating signal起动信号actuator sensor interface AS接口acyclic非循环adapter cable适配器电缆adapter card适配卡additional document其它文档add-on terminal附加端子-----------------------Page2-----------------------address assignment list地址分配列表address ID地址IDaddress identifier地址标识符address monitoring地址监视address type地址类型addressing寻址addressing error寻址错误Advanced Manufacturing Research高级制造研究Advanced Planning&Scheduling高级计划与排程Advisory Research Group顾问研究集团AGAG connection AGAG连接aggregate current总电流agile manufacturing灵活制造alarm报警alarm event报警事件Alarm groups editor报警组编辑器Alarm Logs editor报警日志编辑器alarm view报警视图alarm window报警窗口allocation分配alternating current交流alternative branch替代分支alternative path备择路径Analog alarms editor模拟量报警编辑器analog input module模拟量输入模块analog output module模拟量输出模块analog signal模拟量信号AND operation AND操作AND truth table AND真值表angular circular connector有角圆形连接器angular power connector housing角形电源接头外壳ANY pointer ANY指针Any transition任意跳转API function API函数application应用application memory应用程序存储器application module应用模块Apply button“应用”按钮approach velocity逼近速度archiving归档area区域area-crossing indirect addressing跨区域间接寻址area-crossing register-indirect addressing跨区域寄存器间接寻址array element数组元素ASCII driver ASCII驱动程序ASCII text file ASCII文本文件AS-i bus AS-i总线AS-i module AS接口模件AS-i system AS-i系统Asian characters亚洲语言字符assign parameters分配参数assignment list分配列表asymmetrical signal非对称信号AT bus AT总线attribute属性-----------------------Page3----------------------authorization授权authorization level授权级别automatic single block自动单独块automatic speed control转速控制automation system自动化系统autorepeat自动重复AUX bus辅助总线auxiliary networks辅助网络available capability可用能力available UDP connection可用的UDP连接axis label轴标签B stack B栈background color背景色background task后台任务backplane bus背板总线backspace key Backspace键back-up battery备用电池backwards向后base connector底座连接器basic cabinet基础机柜basic chart基本计划basic control基本控制basic module基础模块basic operation基本操作basic project基本项目basic version基本版本batch批次batch control批控制batch data批数据batch data management批数据管理Batch data processing批数据处理batch management批管理batch overview批总览batch planning list批计划列表batch process批处理batch status list批状态列表battery low电池电量不足battery module电池模块attery power supply电池电源baud波特BERO signal BERO信号BFOC connector BFOC连接器bill of lading提货单bill of material物料单bill of resources资源清单binary code二进制代码binary coded decimal二进制编码的十进制binary form二进制形式binary result二进制结果binary result bit二进制结果位binary-coded decimal二进制编码的十进制bit accumulator位累加器bit address位地址bit combination位组合bit instruction位指令-----------------------Page4----------------------bit memory位存储器bit memory address area位存储器地址区bit message procedure位消息程序bit pattern位模式bit time unit位时间单位bit/s位/秒bit-by-bit逐位bit-coded command位编码命令bit-coded setting位编码设置block architecture块结构block call command块调用命令block catalog块目录block check块检查block comment块注释block diagram方框图block header块标题Block icon块图标block input块输入block interface块接口block name块名称block number块编号block output块输出block protection块保护block type块类型block type import块类型导入block variable块变量block-oriented execution model面向块的执行模型blue screen蓝屏board driver板驱动程序board retainer电路板护圈Boolean logic布尔逻辑boot diskette启动盘boot loader引导装载程序Boot Sequence引导顺序booting引导border边框border width边框宽度box ID接线盒IDbranch分支branch&merge分支和合并breakpoint断点bridge桥接broadcast广播brochure手册broken cable断路电缆Browse浏览buffer缓冲区buffer overflow缓冲区溢出built-in pointer内置指针bus connection总线连接bus connector总线接头bus link总线连接bus node总线节点bus parameters总线参数bus protocol总线协议-----------------------Page5-----------------------bus system总线系统business model业务模型business objects业务对象button in the toolbar工具栏中的按钮byte address字节地址C7program C7程序cable grip电缆夹cable guide电缆导管call statement调用语句cam controller凸轮控制器Cancel button“取消”按钮cancel Time-of-Day interrupt取消时钟中断cascading menu层叠式菜单catalog window目录窗口cause of the problem问题原因CBA CBA(基于组件的自动化) CCD camera CCD相机central controller中央控制器certificate of analysis检验报告change log更改日志change of operating mode操作模式变化changeover difference切换差程channel DLL通道DLLcharacter frame位字符帧character string字符串characteristic特性chart图表chart element图表元素chart folder图表文件夹chart overview图表总览chart properties图表属性chatter monitoring抖动监视check box复选框check mark复选标记chronological reporting按时间顺序报告circular connector圆形连接器clearance空隙click单击climatic environmental conditions环境气候条件clipboard剪贴板clock时钟Clock Generator时钟生成器clock memory时钟存储器clock prompt时钟提示clock pulse时钟脉冲clock pulse generator function时钟脉冲生成器功能clock synchronized时钟同步clock timing时钟定时clock-pulse rate时钟脉冲速率Close button“关闭”按钮closed-loop controller闭环控制器code generation代码生成coding key编码键coding plug编码插头coil inrush线圈涌入-----------------------Page6-----------------------cold restart冷启动color display彩色显示color-coding颜色编码combo box组合框command boundary命令约束command button命令按钮command macro命令宏command output disable命令输出禁用command set命令集comment注释comment block注释块commissioning开机调试committed capability承诺能力common data management公用数据管理common mode error共模错误common mode interference共模干扰common mode voltage共模电压common resource公用资源communication driver通讯驱动程序communication error通讯错误communication function通讯功能communication function block通讯功能块communication job通讯作业communication peer通讯对等方communication procedures通信程序communication service通讯服务communications通讯compact information压缩信息comparator比较器comparison error比较错误comparison operation比较操作compile编译compiler编译器complex data type复杂数据类型component project组件项目component view组件视图compress压缩condition code bit条件代码位conditional call条件调用conducted传导configuration组态configuration data组态数据configuration error组态错误configuration parameter组态参数configuration table组态表configured connection已组态的连接configuring PC组态PCconnecting cable连接电缆connecting two programming devices连接两台编程设备connection box接线盒connection resource连接资源connection table连接表Connections editor连接编辑器consistency check一致性检查consumables消耗品-----------------------Page7-----------------------context menu右键快捷菜单context-sensitive information上下文相关的信息Continue button“继续”按钮continuous counting无限计数continuous process连续过程continuous turning连续转动contrast control对比度控制control block控制块control cabinet开关柜control command控制命令control element控制元素control libraries控制库control loop控制环control module控制模块control operation控制操作control program控制程序control recipe控制配方control recipe phase控制配方阶段control signal控制信号control system控制系统controlled positioning受控定位controller output控制器输出control-menu box控制菜单框convention约定conversion operation转换操作Converter manual转换器手册cooling冷却coordination control协调控制copy cursor复制光标count mode计数模式count up向上计数count value计数值counter计数器counter and comparison instruction计数器和比较指令counter function计数器功能counter input计数器输入counter instruction计数器指令counter library计数器库counter module计数器模块counter number计数器号counter number error计数器编号错误counter output计数器输出counter up向上计数counter word计数器字counting range计数范围counts计数coupler耦合器cover foil覆盖箔CPU operating system CPU操作系统creep speed慢速creepages and clearances爬电距离及电气间隙criteria analysis标准分析crosshair cursor十字准线光标cross-reference list交叉索引列表current consumption电流消耗-----------------------Page8-----------------------Current Good Manufacturing Practices现行良好制造规范current path电流路径cursor光标cursor control光标控制custom installation自定义安装customized自定义cycle循环cycle control point循环控制点cycle duration循环持续时间cycle time循环时间Cycles editor循环编辑器cyclic program processing循环程序处理dash划线data backup数据备份data block数据块data block area数据块区data block element数据块元素data block instruction数据块指令data block length数据块长度data block register数据块寄存器data byte DBB数据字节DBBdata channel数据通道data collection/ccquisition数据收集/采集data communication equipment数据通讯设备data cycle数据循环data cycle time数据循环时间data double word DBD数据双字DBDdata exchange数据交换data exchange broadcast数据交换广播data integrity数据完整性Data Log editor数据记录编辑器data manager数据管理器data model数据模型data record数据记录data record name数据记录名data record number数据记录号data retention数据保持data storage area数据存储区data structure数据结构data terminal equipment数据终端设备data transfer数据传输data type数据类型data type declaration数据类型声明data word数据字database数据库DB access with one statement用一条语句进行的DB访问DB access with two statements用两条语句进行的DB访问DB editor DB编辑器DC power supply直流电源DDE server DDE服务器deactivate取消激活debug调试deceleration time减速时间decimal places小数位数decompilation反编译-----------------------Page9-----------------------default addressing缺省寻址default data缺省数据Default data button“缺省数据”按钮default setting出厂设置default settings缺省设置deflagration爆燃delay element延迟元素derating降低额定值deselect取消选择destination目标destination area目标区destination parameter目标参数destination run-up目标接近detail display详细信息显示detailed window详细信息窗口deterministic behavior确定性特性device设备device manager设备管理器device name设备名称device number设备编号diagnostic buffer诊断缓冲区diagnostic entry诊断条目diagnostic ID诊断IDdiagnostic interface诊断界面diagnostic interrupt诊断中断diagnostic message诊断消息diagnostics诊断diagnostics address诊断地址diagnostics function诊断功能dialog box对话框differential input差分输入differential voltage差分电压digital display数字显示digital input module数字量输入模块digital input/output module数字量输入/输出模块digital output module数字量输出模块DIN rail DIN导轨DIP switch DIP开关direct addressing直接寻址direct current直流direct data exchange直接数据交换direct help cursor直接帮助光标direct I/O access直接I/O访问direct keys直接键directory icon目录图标discontinued停止Discrete alarms editor离散量报警编辑器dispatching production调度生产display显示display axis显示轴display block显示块display class显示等级display element显示元素display mode显示模式display type显示类型-----------------------Page10-----------------------distributed I/O device分布式I/O设备distributed I/Os分布式I/O disturbance variable干扰变量dock停放dot点double evaluation双重判断Double Integer双精度整数double-click双击down-counter向下计数DP delay time DP延迟时间DP identifier DP标识符DP master system DP主站系统DP slave interface DP从站接口DP standard slave DP标准从站DP(DRIVE)DP(驱动器)DP/AS-Interface link DP/AS接口连接drag-and-drop拖放driver generator驱动程序生成器drop-down menu下拉式菜单dummy module占位模块dummy symbols伪符号duplex core双工线芯duration of message消息持续时间dwell time停留时间dynamic connection动态连接dynamic parameter动态参数dynamization动态化earth接地edge detection沿检测edge formation沿形成editing window编辑窗口editor编辑器EEPROM submodule EEPROM子模块electrical data电气数据electrical link module电气连接模块electromagnetic interference field电磁干扰场electronic catalog电子目录electronic current limitation电流限制electronic module电子模块element元素elementary data type基本数据类型ellipse椭圆EM3xx EM3xxE-Mail电子邮件e-mail address电子邮件地址e-mail connection电子邮件连接emergency stop button紧急停止按钮emergency stop circuit紧急停止电路emergency stop push button急停按钮enable input使能输入enable input evaluation启用输入判断enable out使能输出encoder revolution编码器旋转encoder with asymmetrical output signals具有非对称输出信号的编码器encoder with symmetrical output signals具有对称输出信号的编码器-----------------------Page11-----------------------encryption加密end of segment区段终点endstop固定挡块engineering station工程站engineering toolset工程工具集enter key Enter键Enterprise Production Systems企业生产系统entry address条目地址entry field输入域entry ID条目IDequidistant mode等距离equipment class设备分类equipment control设备控制equipment manual机器手册equipment module设备模块equipment operation设备操作equipment phase设备阶段equipotential bonding等电位连接equipotential bonding strip等电位铅条error analysis错误诊断error detection错误检测error diagnostics错误诊断error event错误事件error filter错误过滤器error information错误信息error log错误日志error organization block错误组织块error register错误寄存器ERROR-SEARCH mode ERROR-SEARCH模式ES工程系统event synchronous同步事件event triggered事件触发event-driven事件驱动event-driven program processing事件驱动的程序处理Ex analog input防爆保护模拟量输入Ex analog output防爆保护模拟量输出Ex digital input防爆保护数字量输入Ex digital output防爆保护数字量输出Ex partition防爆保护分区exception handling例外处理exclusion addresses排除地址executability可执行性execution load执行负载execution monitor执行监视execution status执行状态execution time执行时间execution time limit执行时间限制expand docked window展开停放窗口expansion扩展expansion bus扩展总线expansion dialog box扩展对话框export file导出文件expression表达式extended temperature range扩展的温度范围extender扩展器-----------------------Page12-----------------------extension module扩展模块external fault外部故障external input外部输入external view外部视图extraction tool插拔件工具faceplate面板fan subassembly风扇部件fan-out connector接线端块fan-out unit扇出单元fault故障fault current故障电流fault message故障信息fault-tolerant system容错系统FBD editor CSF编辑器FC功能fetch principle获取原理FIBER OPTIC CABLE光缆field现场field bus isolating transformer现场总线隔离变压器field device现场设备field element现场元件fieldbus现场总线filler element填充元素filter criteria过滤条件finished good waivers成品弃权声明书finished goods成品first input bit scan第一个输入位扫描fixed functionality修复的功能fixed setpoint control固定设定值控制fixed-point number定点数flag标志flash闪烁flash card闪存卡flash DIMM modules闪存DIMM模块flash EPROM闪存EPROMflash memory闪存flexible connection软连接floating-point format浮点格式FMS client FMS客户机FMS connection FMS连接FMS server FMS服务器focus聚焦folder文件夹following block后续块following error limit跟踪误差限制follow-up mode跟进模式font scheme字体方案for data用于数据FOR statement FOR语句force value强制值forced execution sleep time强制执行休眠时间forcing强制formal operand形式操作数formatting格式化formula公式-----------------------Page13-----------------------forwards向前four-fold evaluation四重判断free cycle空闲周期free edit mode自由编辑模式free port空闲端口frequency meter频率计front connector module前连接器模块full-duplex mode全双工模式full-stroke keyboard全程键盘function block功能块function block library功能块库function designation功能名称function diagram工作原理图function grounding功能接地function key功能键function module功能模块function value函数值functional unit功能单元fuse blown保险丝熔断fusible link熔线fuzzy control模糊控制gain增益gate stop function门停止功能gateway网关GD circle GD电路GD element GD元素GD package GD包geared synchronous motion齿轮同步运动general monitoring常规监视generate生成generator生成器generic block通用块generic properties通用属性generic station description GSD文件generic term专业术语global communication全局通讯global data identifier全局数据标识符global data table全局数据表GOTO statement GOTO语句graph group图形组graphic图形graphic display图形显示graphic editor图形编辑器graphic language图形语言Graphic List editor图形列表编辑器graphic object图形对象graphic plotter绘图仪graphics device图形设备Graphics editor图形编辑器graphics list图形列表grid网格ground fault detector接地故障检测器grounding wrist strap接地腕带group acknowledgement组确认Groups editor组编辑器-----------------------Page14-----------------------guide line准则H station H站half-duplex mode半双工模式half-tone color半色调颜色handwheel手轮hard disk硬盘hard disk access硬盘访问hard disk drive硬盘驱动器hard disk memory硬盘存储器hardware catalog硬件目录hardware configuration硬件组态hardware fault硬件故障hardware gate硬件门hardware information硬件信息header标题header area标题区header-end标题结尾Help button“帮助”按钮hierarchy branch体系分支hierarchy folder体系文件夹hierarchy level体系层级high-availability高可用性higher level designation of item条目的更高层名称higher order更高顺序higher priority更高优先级highest station address最高站地址HiGraph HiGraphHold button“保持”按钮HOLD mode HOLD模式hot swapping热交换hub集线器hue色调I/O area I/O区I/O bus I/O总线I/O:external input I/O：外部输入I/O:external output I/O：外部输出IBM character set IBM字符集identification标识identification data标识数据identifier符号，名称identifier-related diagnostic data标识符相关诊断数据IF Slot IF插槽illuminated pushbutton发光按钮开关image evaluation system图像评估系统image processing图像处理image processing system图像处理系统immediate addressing立即寻址import file导入文件import/export wizard导入/导出向导in/out parameter输入/输出参数inching mode微动模式incoming event进入事件incremental edit mode增量编辑模式incremental position encoder增量编码器incremental text selection增量文本选择-----------------------Page15-----------------------increments/revolution增量/转indent缩进indirect addressing间接寻址inductive load电感负载Industrial Ethernet工业以太网inert惰性infobox信息框information function信息功能infotext信息文本initial diagnostic address初始诊断地址initial message初始消息initial start初始启动initialization phase初始化阶段initialize初始化initiate启动in-process waiver requests进行中弃权请求input输入input bit输入位input byte输入字节input delay输入延迟input double word输入双字input filter输入过滤器input module模拟的输入input parameter输入参数input point输入点input word输入字input/output输入/输出input/output module输入/输出模块inrush current突入电流insert mode插入模式insert point插入点installation frame安装框架installation instructions安装说明installation work安装工作instance实例instance data背景数据instance data block背景数据块instance name实例名称instruction指令instruction sequence指令顺序Instructions for system upgrade系统升级说明instrumentation and control仪器和控制integer整数integrated user memory集成用户存储器integration集成intelligent DP slave智能DP从站intelligent I/O module智能I/O模块interactive step交互式步骤interface接口Interface DB接口DBinterface for memory submodules存储器子模块接口interface module接通interference frequency suppression干扰频率抑制interference immunity抗干扰interference voltage干扰电压-----------------------Page16-----------------------interlock互锁interlock time互锁时间internal error内部错误internally current limited内部电流限制interprocessor communication flag处理器间通讯标志interrupt报警interrupt organization block中断组织块interrupt stack中断堆栈invitation to tender招标ISA module ISA模块ISA slot ISA插槽isochronous mode同步模式isolation transformer隔离变送器IT system IT系统jitter抖动job number作业号jump跳转jump destination跳转目标kernel内核key business drivers关键业务驱动因素Key Performance Indicator关键性能指示器keyboard controller键盘控制器keyboard driver键盘驱动程序key-operated switch钥匙键控开关keyword关键字L terminal L端子label as address标签作为地址labeling strip标签条Ladder Diagram梯形图Ladder Editor梯形图编辑器language element语言元素language subset语言子集leakage current漏电流learnability可学习性length measurement长度测量length of the network网络长度level层，平面level1functions1级功能level2functions2级功能level3functions3级功能level4functions4级功能level monitoring电平调整level-controlled电平控制library number库号limit switch限制开关line comment行注释line style线型line width线宽linear addressing线性寻址linear axis线性轴linear scale线性转换link cursor链接光标link device连接设备LINK-UP mode LINK-UP模式link-up system mode连接系统模式-----------------------Page17-----------------------liquid crystal液晶list view列表视图literal文字的load circuit负载电路load command装载命令load current supply负载电流源load instruction装载指令load memory装载存储器load monitor监视器load object装载对象load timer in binary format装入二进制格式的定时器load user program装载用户程序load wiring负载接线local area network局域网local bus局部总线local data局部数据local data bit局部数据位local data byte局部数据字节local data double word局部数据双字local data stack局部数据堆栈local PROFIBUS address本地PROFIBUS地址local to block symbols本地块符号local variable局部变量location cursor位置光标location designation位置指定location-independent位置独立locked已锁定log on登录logarithmic scale对数刻度logic block逻辑块logic operation逻辑操作logical communication link逻辑通讯连接login登录long-term archive长期归档loop环路Loop control循环控制loop display循环显示loop-in-alarm报警循环lot批M7DDE server M7DDE服务器main chart主图表main memory主存储器main SETUP menu主“设置”菜单Maintenance Station维护站major tick marks主核对符号malfunction故障manufacturing automation protocol制造自动化协议manufacturing cell制造单元Manufacturing Execution Systems制造执行系统Manufacturing Operations and Control domain制造运营与控制领域marking标记master主站master computer主计算机Master Control Relay主控继电器master controller主控制器-----------------------Page18-----------------------master data主数据master interface module主站接口模块master project主项目master recipe phase主配方阶段material class材料分类material definition材料定义material lot材料批号material model材料模型Material Requirements Planning物料需求计划material sublot材料子批mathematical functions数学函数maximize最大化maximum execution load最大执行负载MCR area MCR区MCR stack MCR堆栈MCR stack pointer MCR堆栈指针measured value resolution测量值精度measurement type测量类型measuring point测量点measuring system测量系统Media Access Control媒体访问控制membrane keyboard覆膜键盘memory area存储区memory bit存储器位memory byte存储器字节Memory Cache存储器缓存memory card存储卡Memory card port存储卡端口memory double word存储器双字memory expansion存储器扩展memory location存储位置memory module存储器模块memory reset存储器复位menu菜单menu assisted辅助菜单menu bar菜单栏menu entry菜单条目menu item菜单项menu title菜单标题message显示信息message acknowledgement消息确认message bit procedure消息位程序message buffer消息缓冲区message burst消息脉冲串message class消息类别message format消息格式message frame消息帧message indicator消息指示灯message line消息行message number消息号message number procedure消息号程序message output消息输出message procedure消息程序message sequence report消息顺序报告message status消息状态-----------------------Page19-----------------------message tag消息变量message text消息文本message-type block消息类型块metal guide金属导轨micro memory card微型存储卡migration移植mimic模拟minimize最小化minimum cycle time最小循环时间minimum ignition energy最小点火能量minimum sleep time最小休眠时间minor tick marks次核对符号missing encoder supply缺少编码器电源missing load voltage L+缺少负载电压L+ mode运行方式mode of operation操作模式mode selector模式选择器model模型models for Manufacturing Execution Systems制造执行系统模型modem调制解调器modifying times修改时间modular closed-loop control模块化闭环控制modular PID control模块化PID控制modulator quiet time调整器静态时间module模块module backplane模块背板module cl模块种类module identifier模块标识符module number模块编号module parameters模块参数module position模块位置module status模块状态monitor监视器monitor interval监控间隔monitor variables监控变量monitoring logic监视逻辑monitoring point监视点monitoring time监视时间monitoring type监视类型monoflop单稳态触发器motherboard主板motion monitoring运动监视motor block电机块mouse鼠标mouse driver鼠标驱动程序MPI card MPI卡multicomputing多值计算multicomputing interrupt多值计算中断multidimensional field多维域multi-instance多实例multiple document interface多文档界面multiple option多选项multiple option list多选项列表multiplexing多路复用multi-point interface多点接口-----------------------Page20-----------------------multiproject多项目multitasking多任务处理multiturn encoder多匝编码器multi-user system多用户系统multi-vendor多家厂商naming convention命名约定NCM NCMnegative edge transition负跳沿跳转nesting depth嵌套深度NETPRO NETPRO network网络network component网络组件network configuration网络组态network connection网络连接network drive网络驱动器network station网络站network view网络视图node节点node address节点地址node initialization节点初始化noise噪音no-load voltage空载电压non-condensing非结露non-configured connection非组态的连接non-deterministic behavior非确定性特性non-hazardous area非危险区non-isolated非隔离non-modal dialog box非模态对话框NOP step NOP步骤NOP transition NOP跳转normally closed contact常闭触点null instruction空指令NW电网或电源系统OB number OB编号OB priority OB优先级object linking and embedding对象链接和嵌套object properties对象属性object view对象窗口OFF delay OFF延迟offline离线offline mode离线模式oil immersion'o'油浸'o'OK button“确定”按钮old value旧值onboard I/O板载I/Oon-delay timer接通延迟定时器one's complement一的补码online在线online mode在线模式on-the-fly control实时测量OPC server OPC服务器Open button“打开”按钮open picture打开图片open-loop control开环控制Open-Loop Positioning开环定位-----------------------Page21-----------------------operating data操作数据operating information range操作信息范围Operating Instructions操作指令operating resource操作资源operating system操作系统operating system run time操作系统运行时间operating text操作文本operation操作operation in segmented rack以分段机架运行operation message操作消息operational limit操作限制operational message运作消息operations and detailed scheduling实施和详细排程operator action操作员动作operator authorization操作员授权operator control and monitoring操作员控制和监视operator control and monitoring system操作员控制和监视系统operator control enable操作员控制启用operator input操作员输入operator mode操作员模式operator protection操作员保护operator unit操作单元optical link module光连接模块optical link plug光连接插头optically isolated光隔离optional software可选软件order number订货号organization block组织块organizational chart组织图organizational function chart组织功能图outline view大纲视图output输出output bit输出位output byte输出字节output circuit输出电路output coil绕组，线圈output double word输出双字output organizer输出管理器output parameter输出参数output range输出范围output signal输出信号Output Window输出窗口output word输出字overcurrent protection过流保护overflow溢出overflow page溢出页override倍率page footer页脚pane窗格panel面板parallel branch并联支路parallel connection并联parameter assignment参数分配parameter connection point参数连接点parameter control参数控制-----------------------Page22-----------------------parameter description参数描述parameter field参数域parameter settings参数设置parameter type参数类型parameterization参数化parity奇偶校验partial process image部分过程映像participant参与者partition分区PC adapter PC适配器PC carrier board PC载板PC DDE server PC DDE服务器PC slave board PC从板PC/PPI cable PC/PPI电缆peer对等方peripheral外设peripheral input byte外设输入字节peripheral input double word外设输入双字peripheral input word外设输入字peripheral output byte外设输出字节peripheral output double word外设输出双字peripheral output word外设输出字permanent instruction永久指令permanent window永久窗口Personal Computer个人计算机personnel class人员分类PG/OP communication PG/OP通讯phased-out product逐渐停产的产品physical address物理地址physical communication connection物理通讯连接PIC unit PIC单元pigtail set引出端装置pin application插脚pinion副齿轮pixel graphics像素图形plan interface计划接口plan-oriented execution model面向计划的执行模型Plant Asset Management工厂资产管理plant comment设备注释plant control level设备控制级plant stoppage设备停机plant view设备视图plausibility check似然性检查pliers钳子plot绘图plug connector插头连接器plug-in contact插入式触点pointer指针pointer constant指针常量pointer format指针格式pointer instrument指针式仪表point-to-point点对点poll cycle time轮询周期polyline折线popup window弹出式窗口-----------------------Page23-----------------------position controller位置调节器position decoder module位置解码器模块position detection位置检测position monitoring位置监视position-control cycle位置控制周期positioning定位positioning accuracy定位精度positioning action定位操作positioning module定位模块positioning time定位时间positive edge transition正跳沿转换positive signal edge信号正跳沿power connector电源连接器power drive动力传动装置power failure电源故障power loss功率损耗power management电源管理power module功率模块power supply电源power supply error电源故障power supply module电源模块power up加电pre-assign预分配predecessor step前导步骤prefabricated预制的pre-fabricated预制preset configuration预置组态preset variable事先调整变量pressurized cooling加压冷却priority class优先级等级problem-free无故障。

JVM for a Heterogeneous Shared Memory SystemDeQing Chen,Chunqiang Tang,Sandhya Dwarkadas,and Michael L.ScottComputer Science Department,University of Rochester AbstractInterWeave is a middleware system that supports the shar-ing of strongly typed data structures across heterogeneouslanguages and machine architectures.Java presents spe-cial challenges for InterWeave,including write detection,data translation,and the interface with the garbage col-lector.In this paper,we discuss our implementation ofJ-InterWeave,a JVM based on the Kaffe virtual machineand on our locally developed InterWeave client software.J-InterWeave uses bytecode instrumentation to detectwrites to shared objects,and leverages Kaffe’s class ob-jects to generate type information for correct transla-tion between the local object format and the machine-independent InterWeave wire format.Experiments in-dicate that our bytecode instrumentation imposes lessthan2%performance cost in Kaffe interpretation mode,and less than10%overhead in JIT mode.Moreover,J-InterWeave’s translation between local and wire format ismore than8times as fast as the implementation of ob-ject serialization in Sun JDK1.3.1for double arrays.Toillustrate theflexibility and efficiency of J-InterWeave inpractice,we discuss its use for remote visualization andsteering of a stellar dynamics simulation system writtenin C.1IntroductionMany recent projects have sought to support distributedshared memory in Java[3,16,24,32,38,41].Manyof these projects seek to enhance Java’s usefulness forlarge-scale parallel programs,and thus to compete withmore traditional languages such as C and Fortran in thearea of scientific computing.All assume that applicationcode will be written entirely in Java.Many—particularlythose based on existing software distributed shared mem-ory(S-DSM)systems—assume that all code will run oninstances of a common JVM.has yet to displace Fortran for scientific computing sug-gests that Java will be unlikely to do so soon.Even for systems written entirely in Java,it is appealing to be able to share objects across heterogeneous JVMs. This is possible,of course,using RMI and object serial-ization,but the resulting performance is poor[6].The ability to share state across different languages and heterogeneous platforms can also help build scalable dis-tributed services in general.Previous research on var-ious RPC(remote procedure call)systems[21,29]in-dicate that caching at the client side is an efficient way to improve service scalability.However,in those sys-tems,caching is mostly implemented in an ad-hoc man-ner,lacking a generalized translation semantics and co-herence model.Our on-going research project,InterWeave[9,37],aims to facilitate state sharing among distributed programs written in multiple languages(Java among them)and run-ning on heterogeneous machine architectures.InterWeave applications share strongly-typed data structures located in InterWeave segments.Data in a segment is defined using a machine and platform-independent interface de-scription language(IDL),and can be mapped into the ap-plication’s local memory assuming proper InterWeave li-brary calls.Once mapped,the data can be accessed as ordinary local objects.In this paper,we focus on the implementation of In-terWeave support in a Java Virtual Machine.We call our system J-InterWeave.The implementation is based on an existing implementation of InterWeave for C,and on the Kaffe virtual machine,version1.0.6[27].Our decision to implement InterWeave support directly in the JVM clearly reduces the generality of our work.A more portable approach would implement InterWeave support for segment management and wire-format trans-lation in Java libraries.This portability would come,how-ever,at what we consider an unacceptable price in perfor-mance.Because InterWeave employs a clearly defined internal wire format and communication protocol,it is at least possible in principle for support to be incorporated into other JVMs.We review related work in Java distributed shared state in Section2and provide a brief overview of the Inter-Weave system in Section3.A more detailed description is available elsewhere[8,37].Section4describes the J-InterWeave implementation.Section5presents the results of performance experiments,and describes the use of J-InterWeave for remote visualization and steering.Sec-tion6summarizes our results and suggests topics for fu-ture research.2Related WorkMany recent projects have sought to provide distributed data sharing in Java,either by building customized JVMs[2,3,24,38,41];by using pure Java implementa-tions(some of them with compiler support)[10,16,32]; or by using Java RMI[7,10,15,28].However,in all of these projects,sharing is limited to Java applications. To communicate with applications on heterogeneous plat-forms,today’s Java programmers can use network sock-ets,files,or RPC-like systems such as CORBA[39].What they lack is a general solution for distributed shared state. Breg and Polychronopoulos[6]have developed an al-ternative object serialization implementation in native code,which they show to be as much as eight times faster than the standard implementation.The direct compari-son between their results and ours is difficult.Our exper-iments suggest that J-Interweave is at least equally fast in the worst case scenario,in which an entire object is mod-ified.In cases where only part of an object is modified, InterWeave’s translation cost and communication band-width scale down proportionally,and can be expected to produce a significant performance advantage.Jaguar[40]modifies the JVM’s JIT(just-in-time com-piler)to map certain bytecode sequences directly to na-tive machine codes and shows that such bytecode rewrit-ing can improve the performance of object serialization. However the benefit is limited to certain types of objects and comes with an increasing price for accessing object fields.MOSS[12]facilitates the monitoring and steering of scientific applications with a CORBA-based distributed object system.InterWeave instead allows an application and its steerer to share their common state directly,and in-tegrates that sharing with the more tightly coupled sharing available in SMP clusters.Platform and language heterogeneity can be supported on virtual machine-based systems such as Sun JVM[23] and [25].The Common Language Run-time[20](CLR)under framework promises sup-port for multi-language application development.In com-parison to CLR,InterWeave’s goal is relatively modest: we map strongly typed state across languages.CLR seeks to map all high-level language features to a common type system and intermediate language,which in turn implies more semantic compromises for specific languages than are required with InterWeave.The transfer of abstract data structures wasfirst pro-posed by Herlihy and Liskov[17].Shasta[31]rewrites bi-nary code with instrumentation for access checks forfine-grained S-DSM.Midway[4]relies on compiler support to instrument writes to shared data items,much as we do in the J-InterWeave JVM.Various software shared memory systems[4,19,30]have been designed to explicitly asso-ciate synchronization operations with the shared data they protect in order to reduce coherence costs.Mermaid[42] and Agora[5]support data sharing across heterogeneous platforms,but only for restricted data types.3InterWeave OverviewIn this section,we provide a brief introduction to the design and implementation of InterWeave.A more de-tailed description can be found in an earlier paper[8]. For programs written in C,InterWeave is currently avail-able on a variety of Unix platforms and on Windows NT. J-InterWeave is a compatible implementation of the In-terWeave programming model,built on the Kaffe JVM. J-InterWeave allows a Java program to share data across heterogeneous architectures,and with programs in C and Fortran.The InterWeave programming model assumes a dis-tributed collection of servers and clients.Servers maintain persistent copies of InterWeave segments,and coordinate sharing of those segments by clients.To avail themselves of this support,clients must be linked with a special In-terWeave library,which serves to map a cached copy of needed segments into local memory.The servers are the same regardless of the programming language used by clients,but the client libraries may be different for differ-ent programming languages.In this paper we will focus on the client side.In the subsections below we describe the application programming interface for InterWeave programs written in Java.3.1Data Allocation and AddressingThe unit of sharing in InterWeave is a self-descriptive data segment within which programs allocate strongly typed blocks of memory.A block is a contiguous section of memory allocated in a segment.Every segment is specified by an Internet URL and managed by an InterWeave server running at the host indi-cated in the URL.Different segments may be managed by different servers.The blocks within a segment are num-bered and optionally named.By concatenating the seg-ment URL with a block number/name and offset(delim-ited by pound signs),we obtain a machine-independent pointer(MIP):“/path#block#offset”. To create and initialize a segment in Java,one can ex-ecute the following calls,each of which is elaborated on below or in the following subsections:IWSegment seg=new IWSegment(url);seg.wl_acquire();MyType myobj=new MyType(seg,blkname);myobj.field=......seg.wl_release();In Java,an InterWeave segment is captured as an IWSegment object.Assuming appropriate access rights, the new operation of the IWSegment object communi-cates with the appropriate server to initialize an empty segment.Blocks are allocated and modified after acquir-ing a write lock on the segment,described in more detail in Section3.3.The IWSegment object returned can be passed to the constructor of a particular block class to al-locate a block of that particular type in the segment. Once a segment is initialized,a process can convert be-tween the MIP of a particular data item in the segment and its local pointer by using mip ptr and ptr mip where appropriate.It should be emphasized that mip ptr is primar-ily a bootstrapping mechanism.Once a process has one pointer into a data structure(e.g.the root pointer in a lat-tice structure),any data reachable from that pointer can be directly accessed in the same way as local data,even if embedded pointers refer to data in other segments.In-terWeave’s pointer-swizzling and data-conversion mech-anisms ensure that such pointers will be valid local ma-chine addresses or references.It remains the program-mer’s responsibility to ensure that segments are accessed only under the protection of reader-writer locks.3.2HeterogeneityTo accommodate a variety of machine architectures,In-terWeave requires the programmer to use a language-and machine-independent notation(specifically,Sun’s XDR[36])to describe the data types inside an InterWeave segment.The InterWeave XDR compiler then translates this notation into type declarations and descriptors appro-priate to a particular programming language.When pro-gramming in C,the InterWeave XDR compiler generates twofiles:a.hfile containing type declarations and a.c file containing type descriptors.For Java,we generate a set of Java class declarationfiles.The type declarations generated by the XDR compiler are used by the programmer when writing the application. The type descriptors allow the InterWeave library to un-derstand the structure of types and to translate correctly between local and wire-format representations.The lo-cal representation is whatever the compiler normally em-ploys.In C,it takes the form of a pre-initialized data struc-ture;in Java,it is a class object.3.2.1Type Descriptors for JavaA special challenge in implementing Java for InterWeave is that the InterWeave XDR compiler needs to gener-ate correct type descriptors and ensure a one-to-one cor-respondence between the generated Java classes and C structures.In many cases mappings are straight forward: an XDR struct is mapped to a class in Java and a struct in C,primitivefields to primitivefields both in Java andC,pointersfields to object references in Java and pointers in C,and primitive arrays to primitive arrays. However,certain“semantics gaps”between Java and C force us to make some compromises.For example,a C pointer can point to any place inside a data block;while Java prohibits such liberties for any object reference. Thus,in our current design,we make the following compromises:An InterWeave block of a single primitive data item is translated into the corresponding wrapped class for the primitive type in Java(such as Integer,Float, etc.).Embedded structfields in an XDR struct definition areflattened out in Java and mapped asfields in its parent class.In C,they are translated naturally into embeddedfields.Array types are mapped into a wrapped IWObject(including the IWacquire,wl acquire, and rlpublic class IWSegment{public IWSegment(String URL,Boolean iscreate);public native staticint RegisterClass(Class type);public native staticObject mip_to_ptr(String mip);public native staticString ptr_to_mip(IWObject Ob-ject obj);......public native int wl_acquire();public native int wl_release();public native int rl_acquire();public native int rl_release();......}Figure2:IWSegment Class4.1.1JNI Library for IWSegment ClassThe native library for the IWSegment class serves as an intermediary between Kaffe and the C InterWeave library. Programmer-visible objects that reside within the IWSeg-ment library are managed in such a way that they look like ordinary Java objects.As in any JNI implementation,each native method has a corresponding C function that implements its function-ality.Most of these C functions simply translate their pa-rameters into C format and call corresponding functions in the C InterWeave API.However,the creation of an In-terWeave object and the method RegisterClass need special explanation.Mapping Blocks to Java Objects Like ordinary Java objects,InterWeave objects in Java are created by“new”operators.In Kaffe,the“new”operator is implemented directly by the bytecode execution engine.We modi-fied this implementation to call an internal function new-Block in the JNI library and newBlock calls the Inter-Weave C library to allocate an InterWeave block from the segment heap instead of the Kaffe object heap.Before returning the allocated block back to the“new”operator, newBlock initializes the block to be manipulated cor-rectly by Kaffe.In Kaffe,each Java object allocated from the Kaffe heap has an object header.This header contains a pointer to the object class and a pointer to its own monitor.Since C InterWeave already assumes that every block has a header (it makes no assumption about the contiguity of separate blocks),we put the Kaffe header at the beginning of what C InterWeave considers the body of the block.A correctly initialized J-InterWeave object is shown in Figure3.Figure3:Block structure in J-InterWeaveAfter returning from newBlock,the Kaffe engine calls the class constructor and executes any user cus-tomized operations.Java Class to C Type Descriptor Before any use of a class in a J-InterWeave segment,including the creation of an InterWeave object of the type,the class object must befirst registered with RegisterClass.Register-Class uses the reflection mechanism provided by the Java runtime system to determine the following informa-tion needed to generate the C type descriptor and passes it to the registration function in the C library.1.type of the block,whether it is a structure,array orpointer.2.total size of the block.3.for structures,the number offields,eachfield’s off-set in the structure,and a pointer to eachfield’s type descriptor.4.for arrays,the number of elements and a pointer tothe element’s type descriptor.5.for pointers,a type descriptor for the pointed-to data.The registered class objects and their corresponding C type descriptors are placed in a hashtable.The new-Block later uses this hashtable to convert a class object into the C type descriptor.The type descriptor is required by the C library to allocate an InterWeave block so that it has the information to translate back and forth between local and wire format(see Section3).4.2KaffeJ-InterWeave requires modifications to the byte code in-terpreter and the JIT compiler to implementfine-grained write detection via instrumentation.It also requires changes to the garbage collector to ensure that InterWeave blocks are not accidentally collected.Figure4:Extended Kaffe object header forfine-grained write detection4.2.1Write DetectionTo support diff-based transmission of InterWeave segment updates,we must identify changes made to InterWeave objects over a given span of time.The current C ver-sion of InterWeave,like most S-DSM systems,uses vir-tual memory traps to identify modified pages,for which it creates pristine copies(twins)that can be compared with the working copy later in order to create a diff.J-InterWeave could use this same technique,but only on machines that implement virtual memory.To enable our code to run on handheld and embedded devices,we pursue an alternative approach,in which we instrument the interpretation of store bytecodes in the JVM and JIT. In our implementation,only writes to InterWeave block objects need be monitored.In each Kaffe header,there is a pointer to the object method dispatch table.On most architectures,pointers are aligned on a word boundary so that the least significant bit is always zero.Thus,we use this bit as theflag for InterWeave objects.We also place two32-bit words just before the Kaffe object header,as shown in Figure4.The second word—modification status—records which parts of the object have been modified.A block’s body is logically divided into32parts,each of which corresponds to one bit in the modification status word.Thefirst extended word is pre-computed when initializing an object.It is the shift value used by the instrumented store bytecode code to quickly determine which bit in the modification status word to set(in other words,the granularity of the write detection).These two words are only needed for In-terWeave blocks,and cause no extra overhead for normal Kaffe objects.4.2.2Garbage CollectionLike distributedfile systems and databases(and unlike systems such as PerDiS[13])InterWeave requires man-ual deletion of data;there is no garbage collection.More-over the semantics of InterWeave segments ensure that an object reference(pointer)in an InterWeave object(block) can never point to a non-InterWeave object.As a result, InterWeave objects should never prevent the collection of unreachable Java objects.To prevent Kaffe from acci-dentally collecting InterWeave memory,we modify the garbage collector to traverse only the Kaffe heap.4.3InterWeave C libraryThe InterWeave C library needs little in the way of changes to be used by J-InterWeave.When an existing segment is mapped into local memory and its blocks are translated from wire format to local format,the library must call functions in the IWSegment native library to initialize the Kaffe object header for each block.When generating a description of modified data in the write lock release operation,the library must inspect the modifi-cation bits in Kaffe headers,rather than creating diffs from the pristine and working copies of the segment’s pages.4.4DiscussionAs Java is supposed to be“Write Once,Run Anywhere”, our design choice of implementing InterWeave support at the virtual machine level can pose the concern of the portability of Java InterWeave applications.Our current implementation requires direct JVM support for the fol-lowing requirements:1.Mapping from InterWeave type descriptors to Javaobject classes.2.Managing local segments and the translation be-tween InterWeave wire format and local Java objects.3.Supporting efficient write detection for objects in In-terWeave segments.We can use class reflection mechanisms along with pure Java libraries for InterWeave memory management and wire-format translation to meet thefirst two require-ments and implement J-InterWeave totally in pure Java. Write detection could be solved using bytecode rewrit-ing techniques as reported in BIT[22],but the resulting system would most likely incur significantly higher over-heads than our current implementation.We didn’t do this mainly because we wanted to leverage the existing C ver-sion of the code and pursue better performance.In J-InterWeave,accesses to mapped InterWeave blocks(objects)by different Java threads on a single VM need to be correctly synchronized via Java object monitors and appropriate InterWeave locks.Since J-InterWeave is not an S-DSM system for Java virtual machines,the Java memory model(JMM)[26]poses no particular problems. 5Performance EvaluationIn this section,we present performance results for the J-InterWeave implementation.All experiments employ a J-InterWeave client running on a1.7GHz Pentium-4Linux machine with768MB of RAM.In experiments involving20406080100120_201_co mp r e s s _202_j e s s _205_ra y t r a c e _209_db _213_j a va c _222_m p e g a u d i o _227_m t r t _228_j a c kJVM98 BenchmarksT i m e (s e c .)Figure 5:Overhead of write-detect instrumentation in Kaffe’s interpreter mode01234567_201_c o mp r e s s _202_j e s s _205_r a y t r a c e _209_d b _213_j a v a c _222_m p e g a u d i o _227_m t r t _228_j a c k JVM98 Benchmarks T i m e (s e c .)Figure 6:Overhead of write-detect instrumentation inKaffe’s JIT3modedata sharing,the InterWeave segment server is running on a 400MHz Sun Ultra-5workstation.5.1Cost of write detectionWe have used SPEC JVM98[33]to quantify the perfor-mance overhead of write detection via bytecode instru-mentation.Specifically,we compare the performance of benchmarks from JVM98(medium configuration)run-ning on top of the unmodified Kaffe system to the per-formance obtained when all objects are treated as if they resided in an InterWeave segment.The results appear in Figures 5and 6.Overall,the performance loss is small.In Kaffe’s inter-preter mode there is less than 2%performance degrada-tion;in JIT3mode,the performance loss is about 9.1%.The difference can be explained by the fact that in inter-preter mode,the per-bytecode execution time is already quite high,so extra checking time has much less impact than it does in JIT3mode.The Kaffe JIT3compiler does not incorporate more re-cent and sophisticated technologies to optimize the gener-ated code,such as those employed in IBM Jalepeno [35]and Jackal [38]to eliminate redundant object referenceand array boundary checks.By applying similar tech-niques in J-InterWeave to eliminate redundant instrumen-tation,we believe that the overhead could be further re-duced.5.2Translation costAs described in Sections 3,a J-InterWeave application must acquire a lock on a segment before reading or writ-ing it.The acquire operation will,if necessary,ob-tain a new version of the segment from the InterWeaveserver,and translate it from wire format into local Kaffeobject format.Similarly,after modifying an InterWeavesegment,a J-InterWeave application must invoke a write lock release operation,which translates modified por-tions of objects into wire format and sends the changes back to the server.From a high level point of view this translation re-sembles object serialization ,widely used to create per-sistent copies of objects,and to exchange objects between Java applications on heterogeneous machines.In this sub-section,we compare the performance of J-InterWeave’stranslation mechanism to that of object serialization in Sun’s JDK v.1.3.1.We compare against the Sun im-plementation because it is significantly faster than Kaffe v.1.0.6,and because Kaffe was unable to successfully se-rialize large arrays in our experiments.We first compare the cost of translating a large array of primitive double variables in both systems.Under Sun JDK we create a Java program to serialize double arrays into byte arrays and to de-serialize the byte arrays backagain.We measure the time for the serialization and de-serialization.Under J-InterWeave we create a programthat allocates double arrays of the same size,releases (un-maps)the segment,and exits.We measure the releasetime and subtract the time spent on communication with the server.We then run a program that acquires (maps)the segment,and measure the time to translate the byte arrays back into doubles in Kaffe.Results are shown in Figure 7,for arrays ranging in size from 25000to 250000elements.Overall,J-InterWeave is about twenty-three times faster than JDK 1.3.1in serialization,and 8times faster in dese-rialization.5.3Bandwidth reduction To evaluate the impact of InterWeave’s diff-based wire format,which transmits an encoding of only those bytes that have changed since the previous communication,we modify the previous experiment to modify between 10and 100%of a 200,000element double array.Results appear in Figures 8and 9.The former indicates translation time,the latter bytes transmitted.20406080100120140250005000075000100000125000150000175000200000225000250000Size of double array (in elements)T i m e (m s e c .)Figure 7:Comparison of double array translation betweenSun JDK 1.3.1and J-InterWeave102030405060708090100100908070605040302010Percentage of changesT i m e (m s e c .)Figure 8:Time needed to translate a partly modified dou-ble arrayIt is clear from the graph that as we reduce the per-centage of the array that is modified,both the translationtime and the required communication bandwidth go down by linear amounts.By comparison,object serialization is oblivious to the fraction of the data that has changed.5.4J-InterWeave Applications In this section,we describe the Astroflow application,developed by colleagues in the department of Physics andAstronomy,and modified by our group to take advan-tage of InterWeave’s ability to share data across hetero-geneous platforms.Other applications completed or cur-rently in development include interactive and incremental data mining,a distributed calendar system,and a multi-player game.Due to space limitations,we do not present these here.The Astroflow [11][14]application is a visualization tool for a hydrodynamics simulation actively used in the astrophysics domain.It is written in Java,but employs data from a series of binary files that are generated sepa-rately by a computational fluid dynamics simulation sys-00.20.40.60.811.21.41.61.8100908070605040302010Percentage of changesT r a n s mi s s i o n s i z e (M B )Figure 9:Bandwidth needed to transmit a partly modified double array2040608010012014012416Number of CPUsT i m e (s e c .)Figure 10:Simulator performance using InterWeave in-stead of file I/Otem.The simulator,in our case,is written in C,and runs on a cluster of 4AlphaServer 41005/600nodes under the Cashmere [34]S-DSM system.(Cashmere is a two-level system,exploiting hardware shared memory within SMP nodes and software shared memory among nodes.InterWeave provides a third level of sharing,based on dis-tributed versioned segments.We elaborate on this three-level structure in previous papers [8].)J-InterWeave makes it easy to connect the Astroflow vi-sualization front end directly to the simulator,to create an interactive system for visualization and steering.The ar-chitecture of the system is illustrated in Figure 1(page 1).Astroflow and the simulator share a segment with one header block specifying general configuration parameters and six arrays of doubles.The changes required to the two existing programs are small and limited.We wrote an XDR specification to describe the data structures we are sharing and replaced the original file operations with shared segment operations.No special care is re-quired to support multiple visualization clients or to con-trol the frequency of updates.While the simulation data。