What Is Grid Storage? Based on current and proposed products, it appears that a grid storage system should include the following: Modular storage arrays: These systems are connected across a storage network using serial ATA disks. The systems can be block-oriented storage arrays or network-attached storage gateways and servers. Common virtualization layer: Storage must be organized as a single logical pool of resources available to users. Data redundancy and availability: Multiple copies of data should exist across nodes in the grid, creating redundant data access and availability in case of a component failure. Common management: A single level of management across all nodes should cover the areas of data security, mobility and migration, capacity on demand, and provisioning. Simplified platform/management architecture: Because common management is so important, the tasks involved in administration should be organized in modular fashion, allowing the autodiscovery of new nodes in the grid and automating volume and file management. Three Basic Benefits Applying grid topology to a storage network provides several benefits, including the following: Reliability. A well-designed grid network is extremely resilient. Rather than providing just two paths between any two nodes, the grid offers multiple paths between each storage node. This makes it easy to service and replace components in case of failure, with minimal impact on system availability or downtime. Performance. The same factors that lead to reliability also can improve performance. Not requiring a centralized switch with many ports eliminates a potential performance bottleneck, and applying load-balancing techniques to the multiple paths available offers consistent performance for the entire network. Scalability. It’s easy to expand a grid network using inexpensive switches with low port counts to accommodate additional servers for increased performance, bandwidth and capacity. In essence, grid storage is a way to scale out rather than up, using relatively inexpensive storage building blocks.
【英文篇名】 Switch Router Operating System Based on a General Operating System 【下载频次】 ☆ 【作者】 潘登; 徐佩霞; 【英文作者】 PAN Deng; XU Pei xia （Department of Electronic Engineering and Information Science; University of Science and Technology of China; Hefei; 230027; China）; 【作者单位】 中国科学技术大学电子工程与信息科学系; 230027; 【文献出处】 数据采集与处理 , Journal of Data Acquisition & Processing, 编辑部邮箱 2003年 04期 期刊荣誉：中文核心期刊要目总览 ASPT来源刊 CJFD收录刊 【中文关键词】 交换式路由器; 通用操作系统; 路由器操作系统; 【英文关键词】 switch router; general operating system; router operating system; 【摘要】 提出了一种将通用操作系统及其上层路由软件移植到交换式路由器平台上的方案。此方案可以向上屏蔽交换式路由器与传统的路由器体系结构上的区别 ,从而把通用操作系统及其上层路由软件移植到交换式路由器的平台上 ;同时兼顾数据通信和管理维护方面的需求 ,为上层路由软件提供了与传统路由器相同的接口 ,从而使基于通用操作系统的路由软件可以在不损失可升级性的条件下快速移植到交换式路由器上。实际应用证实了该方案具有良好的灵活性和兼容性 【英文摘要】 A new solution to port general operating systems and their routing software to switch router is presented. The solution shields the architecture difference between traditional router and switch router to application level software, thus it may support general operating system and their routing software on switch router platform. The solution is also considered as requirements of both data communication and control functions. And same ways of the access and control of the router are provied as traditional ro... 【基金】 国家 8 63计划 ( 863 -3 1 7-0 1 -99)资助项目 【DOI】 CNKI:SUN:SJCJ.0.2003-04-017 【分类号】 TN915.05 【正文快照】 引 言路由器最重要的工作是根据 IP包头和路由、过滤规则转发 IP包。其他功能还包括路由表的维护与路由器系统的维护。实际上路由器可以看成是一种针对 IP网络路由需求而设计的专用计算机。随着因特网所承载的业务的演进 ,因特网对于路由器性能的要求也日渐提高。在交换式路 看看这一篇 文章编号: 100429037 (2003) 0420450205一种基于通用操作系统的交换式路由器操作系统实现潘 登, 徐佩霞(中国科学技术大学电子工程与信息科学系, 合肥, 230027)摘要: 提出了一种将通用操作系统及其上层路由软件移植到交换式路由器平台上的方案。此方案可以向上屏蔽交换式路由器与传统的路由器体系结构上的区别, 从而把通用操作系统及其上层路由软件移植到交换式路由器的平台上; 同时兼顾数据通信和管理维护方面的需求, 为上层路由软件提供了与传统路由器相同的接口, 从而使基于通用操作系统的路由软件可以在不损失可升级性的条件下快速移植到交换式路由器上。实际应用证实了该方案具有良好的灵活性和兼容性。关键词: 交换式路由器; 通用操作系统; 路由器操作系统中图分类号: TN 915105; TP393 文献标识码:A 基金项目: 国家863 计划(8632317201299) 资助项目 收稿日期: 2003203229; 修订日期: 2003206215Switch Router Operating System Based ona General Operating SystemPA N D eng , X U P ei2x ia(Department of Elect ronic Engineering and Info rmat ion Science,U niversity of Science and Techno logy of Ch ina, Hefei, 230027,Ch ina)Abstract: A new so lu t ion to po rt general operat ing system s and their rou t ing sof tw are tosw itch rou ter is p resen ted. The so lu t ion sh ields the arch itectu re difference betw een t radit ionalrou ter and sw itch rou ter to app licat ion level sof tw are, thu s it may suppo rt general operat ingsystem and their rou t ing sof tw are on sw itch rou ter p latfo rm. The so lu t ion is also con sidered asrequ iremen t s of bo th data commun icat ion and con t ro l funct ion s. A nd same w ays of the accessand con t ro l of the rou ter are p rovied as t radit ional rou ter, so rou t ing sof tw are of the generaloperat ing system may be po rted to sw itch rou ter p latfo rm rap idly w ith the upgradeab lef lex ib ility. P ract ical design app roves that the so lu t ion has a good compat ib ility and f lex ib ility.Key words: sw itch rou ter; general operat ing system; rou ter operat ing system引 言路由器最重要的工作是根据IP 包头和路由、过滤规则转发IP 包。其他功能还包括路由表的维护与路由器系统的维护。实际上路由器可以看成是一种针对IP 网络路由需求而设计的专用计算机。随着因特网所承载的业务的演进, 因特网对于路由器性能的要求也日渐提高。在交换式路由器中, 包转发等绝大多数处理已经转移到以端口为中心的硬件中完成, 只有路由规则的生成与维护、网络管理和系统维护等比较复杂的工作仍由软件部分完成。实用中路由器所采用的操作系统可分为三大类: (1) 以Cisco 的IO S 为代表的专用操作系统, 常见于网络骨干节点; (2) 以V xWo rk s 为代表的嵌入式系统, 常见于小型办公ö家用接入设备上; (3)采用通用操作系统的则在骨干节点和用户接入设备上都有这类设备。例如Jun iper 的路由产品就采用L inux 作为操作系统。通用操作系统上的各种路由、网管软件的开发已经有相当长时间, 其功能、性能、稳定性和升级灵活性都很优秀, 但这些软件仍第18卷第4期2003 年12 月数据采集与处理Journal of Data A cquisit ion & P rocessingVo l. 18 No. 4Dec. 2003然是针对传统路由器体系结构开发的, 无法直接应用于新的路由器体系结构。本文提出在通用操作系统的驱动栈中插入一个中间层, 这样对系统内核及和运行在其上的路由、网管等上层软件屏蔽了下层硬件的特殊性, 从而把上层软件和高速硬件平台结合起来。该方案已经应用于高速边缘路由器中, 并表现出了良好的实用性和可扩展性。1 交换式路由器与传统路由器在体系结构上的差别路由器工作在网络的第三层, 其处理工作主要涵盖七层模型中的下三层, 包括: 物理接口处理、数据链路层处理、网络层的路由查找、转发以及队列管理等[1 ]。在传统的路由器体系结构中, 硬件部分只实现物理层的处理, 其余工作需要消耗系统计算资源完成: 包括CPU 周期、内存容量和总线带宽等, 因此性能也受限于这些资源。而在交换式路由器中, 路由处理机仅处理系统维护、路由表维护等少量工作, 数据流的处理都由相对独立的硬件完成, 不再受限于系统计算资源, 因此其性能远优于传统路由器[2 ]。如图1 所示。(a) 传统路由器体系结构(b) 交换式路由器体系结构图1 路由器的逻辑结构 传统路由器和交换式路由器在体系结构方面有明显的区别: 在传统路由器中, 所有的物理接口直接挂接在总线上, 内核可以通过总线直接访问这些接口; 而在交换式路由器中, 只有控制卡是直接挂接在总线上的, 内核必须通过控制卡间接访问各个接口。这导致操作系统内核中代表网络接口的驱动对象的区别: 在传统路由器中, 内核存在若干网络设备驱动对象实例, 每个实例通过总线直接维护一个端口, 为内核及其上面的上层软件提供基本操作支持。而在交换式路由器中, 普通的网络设备驱动对象无法直接维护端口, 也无法支持系统内核和上层软件操作。因此, 交换式路由器体系结构的特殊性使得通用操作系统和上层软件无法直接应用。针对这个问题有两种解决办法: (1) 大量修改内核和各种相关软件的源代码以适应新的体系结构。这种做法存在开发工作量大、周期长、局限性强的缺点, 丧失了使用通用操作系统的灵活性; (2) 在驱动栈中增加一个中间层, 支持普通网络驱动对象所能支持的一切操作, 这样系统内核和上层软件基本上不必修改就可以运行在交换式路由器上。这就是本文所提出的中间层方案。这种方案克服了第一种方法的复杂性, 在保持灵活性的基础上, 可以快速地把通用操作系统及上层软件移植到交换式路由器的硬件平台上。2 中间层设计中间层功能包括数据通信和控制两个方面。从数据通信方面考虑, 每个端口的功能都等效于传统路由器中的一个网络接口, 所以每个物理端口在内核中都应有对应的网络驱动实例。这样才能支持各种上层软件运行, 满足数据通信功能的需要。从控制功能方面考虑, 对上要把每一种可能的逻辑操作映射成硬件操作; 对下要能够和多个设备通信。上层应用包括系统维护、路由软件、网管软件; 下层设备包括处理引擎和端口。控制功能的具体实现和硬件平台有关。考虑到多种应用可能同时操作一个硬件设备, 一种应用也可能同时操作多个设备, 在实现时必须考虑到对于多并发操作的支持。基于上述考虑, 中间层由控制卡驱动模块和若干网络驱动实例组成。在图2 (a, b) 中分别给出了传统路由器的结构与驱动方式以及本文所提出的中间层所处的位置与驱动方式。第4 期潘 登, 等: 一种基于通用操作系统的交换式路由器操作系统实现451图2 中间层的位置与驱动方式 控制卡驱动模块作为中间层的核心, 维护控制卡上所有的端口、内存映射、中断和循环缓冲队列资源。它实现了数据通道和控制通道。对下直接驱动控制卡、与各个端口、处理引擎通信; 对上, 一方面通过内核调用陷阱方式提供控制通道接口; 另一方面向虚拟网络驱动实例提供数据通道接口。虚拟网络驱动实例在操作系统内核为各个物理端口实现网络驱动实例。它们工作在控制卡驱动模块的基础上, 并不直接控制硬件, 故称为虚拟网络驱动实例。虚拟网络驱动实例封装控制卡驱动模块提供的数据传输功能, 并为内核和上层软件提供与普通网络驱动实例相同的调用接口。下面分别给出数据通道和控制通道的实现方案。211 数据通道的功能与实现虚拟网络驱动实例和物理端口是一一对应的。内核数据收发的功能包括3 个方面:(1) 发往某虚拟网络驱动实例的数据包应该由其对应端口输出;(2) 这个端口所收到的包也通过该虚拟网络驱动实例向系统内核提交;(3) 中间层也可以对虚拟网络驱动实例进行流控操作, 以避免因拥塞导致数据丢失。注意到图2 (b) 中的交换结构以定长信元交换数据, 其格式如图3 所示, 其中信元头占4 字节, 包括处理引擎号和端口号域。对于收ö发信元, 处理引擎号和端口号分别为该信元的源端口的和目的端口的对应值。根据图2 (b) 所示的系统结构可知: 由处理引擎号和端口号可以确定端口的物理位置。控制卡驱动模块在其内部的驱动信息数组中维护虚拟网络驱动实例和端口之间的对应关系。图3 数据信元结构发送数据时, 虚拟网络驱动实例从内核网络部分获取待发送的数据, 偕同指向该实例自己的指针一起提交给控制卡驱动模块。一方面, 控制卡驱动模块通过这个指针可以对虚拟网络驱动实例进行流控设置; 另一方面, 控制卡驱动模块根据虚拟网络驱动实例指针查驱动信息表得到目标端口物理位置信息, 包括处理引擎号和端口号。端口物理位置信息将被填充到所有用来承载待发送数据包的信元头中。控制卡驱动模块通过控制卡把信元送到交换结构, 而交换结构和处理引擎分别根据处理引擎号和端口号将信元转发到到目标端口。最后端口从接收到的信元中恢复出原始数据发出。接收数据时, 端口也会将数据拆分到若干信元中逐级上传。考虑到交换结构的循环优先机制, 一个数据包上传的过程可能被来自其他端口的数据抢断。所以控制卡驱动模块对于接收到的信元按源端口位置信息(包括处理引擎号和端口号) 保存到不同的缓冲区中。当接收到该数据包相关的全部信元, 控制驱动模块即可重组该数据, 并根据源端口位置信息查驱动信息表以得到指向该端口对应虚拟网络驱动实例的指针, 进而激活该虚拟网络驱动实例接收数据。虚拟网络驱动实例从控制卡驱动模块中获取数据后, 按照网络驱动的常规方式调用net if- rx 接口向内核提交数据。数据收发实现结构如图4 所示。值得注意的是, 在交换式路由器中, 处理引擎通过交换结构交换的是IP 包; 而通用操作系统中452 数据采集与处理第18 卷图4 数据收发实现结构网络驱动通常处理链路层的帧。即控制卡驱动模块数据通道对上对下的数据格式是不同的。因此, 在发送数据时控制卡驱动模块需要从得到的链路帧中提取IP 包再转发到端口; 而接收数据时则对来自端口的IP 包进行链路帧封装再向上提交。以以太网为例, 需要恢复的包括源和目标站的物理地址、载荷类型和帧校验[3 ]。对于承载IP 包的以太帧, 显然其目标站物理地址和载荷类型[4 ]都是已知的。实现时采用的操作系统是L inux, 通过在虚拟网络驱动源代码中进行设置可以使内核不进行帧校验[5 ]。所以只有源站物理地址未知。如果要求硬件给出真实的源站物理地址, 则增加了硬件的复杂度; 而若在控制卡驱动模块中伪造源物理地址, 则可能导致内核的ARP 管理混乱。为简化硬件设计, 实现时采用了在控制卡驱动模块中伪造源物理地址的办法, 同时修改虚拟网络驱动源代码, 重载帧头处理函数[6 ]。这样内核ARP 表就不受伪造地址的影响, 其获取和刷新通过查询端口ARP 记录实现。212 控制通道的功能与实现控制功能的通信也是基于信元的, 其操作包括维护管理和表同步两类。维护管理主要是进行各种查询, 通常通过若干次双向通信完成。每次通信有效载荷都只有几个字节, 由一个信元即可承载。而表同步则是将上层软件维护的表复制到相关硬件中, 包括ARP 表、路由和分类表等。表同步操作涉及大量数据传输, 需要由多个信元承载。控制功能都是针对设备进行的, 所以在控制ö反馈信元中也必须包括目标设备的物理位置信息。在实际运行期间, 所有的上层应用和设备之间的控制通信复用控制通道, 其特点为:(1) 不同的应用可能同时访问同一设备;(2) 一个应用也可能同时访问多个设备;(3) 同一应用对于同一个设备的操作一般都是顺序的。为支持这种复用操作, 所有承载控制信息和反馈信息的头部除包括目标硬件的物理位置和操作指令外, 还包括命令类型、应用类型信息。控制ö反馈用信元结构如图5 所示。图5 控制ö反馈信元结构图5 中: 处理引擎号和端口号, 确定设备的物理位置; 收ö发信元分别为该信元的源端口的和目的端口的对应值; 命令码在设备和应用之间定义。每种可能的操作分配一个代码; 应用码在控制卡驱动模块和上层应用之间预定义。每种可能的应用分配一个代码。这些应用包含网管、路由维护、硬件维护和ARP 信息获取等。上层应用通过内核调用陷井( IOCTL ) 发起控制通道操作, 同时给出目标设备物理位置、命令类型代码和应用类型代码。控制卡驱动模块把这些信息填充到控制信元中再将其发往设备。设备把这些代码直接复制到反馈信元中, 再在后面追加上反馈信息。控制卡驱动模块为每一种应用分配一个循环缓冲区, 把收到的反馈根据应用类型排入相应队列中。上层应用从其所对应的循环缓冲区中读取反馈信元, 然后根据信元中的物理位置信息、命令码就可以确定该反馈对应的原始命令, 从而对反馈数据进行适当处理。这样就实现了各种控制功能对控制通道的复用。如图6 所示。第4 期潘 登, 等: 一种基于通用操作系统的交换式路由器操作系统实现453图6 控制通信实现结构3 结 论鉴于传统路由器体系结构和交换式路由器体系结构的区别, 通用操作系统及在其上开发的路由软件无法直接应用于交换式路由器。本文提出的中间层方案可以有效地解决这个问题。该方案全面考虑了数据通信和管理维护方面的需求, 为上层提供了与原有模型基本相同的接口, 并使得路由软件在不损失其灵活性和可升级性的条件下直接应用于交换式路由器中。虽然该方案只是在特定的平台和特定的操作系统上得到了实现, 但是不难看出, 这种思路对操作系统并没有特殊的依赖性, 完全可以移植到其他通用操作系统上。本文提出的方案已经在国家863 项目实用化综合接入系统的高速边缘路由器的研制中取得了良好的实际效果。本文为国产高性能路由器的软件开发提出了一种高效快捷的解决方案, 该方案具有良好的应用前景。参考文献:[1 ] Kuro se J F, Ro ss KW. Computer netwo rk ing: a top2dow n app roach featuring the internet [M ]. A ddisonW esley Longman′s P ress, 2001. 332～ 341.[ 2 ] 梁阿磊, 等. 路由器体系结构及其发展[J ]. 小型微型计算机系统, 2001, 8: 943～ 945.[3 ] M edia access cont ro l frame st ructure [S ]. IEEE Std80213, 1998. 36～ 40.[ 4 ] Charles Ho rnig. RFC 894: a standard fo r the t rans2m ission of IP datagram s over Ethernet netwo rk s[S ].198411～ 2.[5 ] Bovet D P. U nderstanding L inux kernel[M ]. O reil2ley P ress, 2002. 683～ 685[ 6 ] Rubini A. L inux device drivers. 2nd edit ion [M ].O r2eilley P ress, 2001. 455～ 458作者简介: 潘 登(19772) , 男, 博士研究生, 研究方向: 网络体系结构、网络安全, E2mail: pandeng@mail. ustc. edu. cn;徐佩霞(19412) , 女, 教授, 博士生导师, 研究方向: 音频视频编码、非线性处理、下一代网络。454 数据采集与处理第18 卷
湖南软件学院计算机专业英语（论文） 第1页 On Information Resources Abstract: With the development of human society, the way people gather information more and more diversified.Information resources as a special social resources, With strategic nature, can spread the properties, it can increase the properties and comprehensive quality characteristics. Information resource with great economic and social value, not only is important to take a new road to industrialization led forces, but also changes the mode of production and social progress in an enormous boost. Keywords: theoretical exploration; information resources; Transformation 1 Introductio Information resources, as a special configuration has a special meaning and forms of social resources, their role is with each passing day growing. Information resources are the basic elements of modern social productive forces, while change in the way of social production and people's way of life enhancement, resulting in an invaluable influence and promote the role. At the same time in the modern society, the content of information resources is continuously expanding to include not only the growing number of natural science information resources, but also times of social science information resources. The availability of information resources and use of attention is whether the growth of a country's comprehensive national strength is an important factor, but also the extent a country is an important symbol of modernization.
计算机英文翻译-谈谈3GTalking about 3G(1) 3G (the third generation) is a specification developed by the International Telecommunication Union for the third generation of mobile communications technology, (analog cellular was the first generation, digital PCS the second). 3G digital cellular technology promises increased bandwidth: up to 384K bit/sec when a device is stationary or moving at pedestrian speed, 128K bit/sec in a car, and 2M bit/sec in fixed applications. GSM (Global System for Mobile Communications) is an open, nonproprietary system that is the dominant cellular technology throughout the world today. GSM uses a variation of the Time Division Multiple Access (TDMA) protocol. Data is digitized and compressed, then sent down a channel with two other streams of user data, each in its own time slot. It operates at either the 900-MHz or 1800-MHz and 1900-MHz frequency band. Another so-called second-generation wireless air interface is CDMA (Code Division Multiple Access). CDMA is a form of multiplexing, which allows numerous signals to occupy a single transmission channel, optimizing the use of available bandwidth. The technology is used in cellular telephone systems in the 800-MHz and 1.9-GHz bands. Current circuit-switched GSM networks transmit data at 9.6K bit/sec or up to 43.2K bit/sec using multitime slot high-speed circuit switched data (HSCSD) upgrades. GSM’s 3G counterpart，Wideband Code Division Multiple Access (WCDMA), offers much higher data speeds. WCDMA can support mobile voice, images, data and video communications at up to 2M bit/sec (local-area access) or 384K bit/sec (wide-area access). The input signals are digitized and transmitted in a coded, spread-spectrum mode over a range of frequencies. A 5 MHz-wide carrier is used, compared with 200 KHz-wide carrier for narrowband CDMA. In fact, 3G technology applies equally to all standards that are being considered, including CDMA2000 in the United States. CDMA2000 can support mobile data communications at speeds ranging from 144K bit/sec to 2M bit/sec. Deployment is in the planning stages. GSM-based packet radio services (GPRS), already extremely popular in Europe, are being rolled out now in the United States. With GPRS, datastreams are broken up into packets of data rather than the continuous stream of GSM circuit-switched networks. Packetized GPRS offers “always on”connectivity versus GSM, where users pay if they occupy a channel and don’t transmit data or voice. GPRS is central to the promise of mobile Internet capability, delivering voice, video and data to subscribers at up to 115K bit/sec. In Europe, GPRS-equipped handsets are projected to be available for the mass market by early 2002. [参考译文] 谈谈3G(1) 3G(第三代)是国际电信联盟为第三代移动通信技术开发的一种规范（模拟蜂窝电话是第一代，数字个人通信服务为第二代）。3G数字蜂窝电话技术承诺增加带宽：当设备是静止的或者以步行速度行进时为384Kbps，在（行进的）汽车中为128Kbps，在固定的应用中为2Mbps。 GSM（全球通）是非专有的开放系统，它是目前遍布全球的主导的蜂窝电话技术。GSM采用时分多址（TDMA）协议的一个变种。数据经数字化和压缩后，连同其他 两个用户数据流一起在一个信道上送出，每个都有自己的时间隙。它工作在900MHz或者1800MHz和1900MHz频段。 另一个所谓的第二代无线天波接口是CDMA（码分多址接入）。它采用一种多路复用的形式，允许很多信号只占一个传输信道，优化了可用带宽的使用。在800MHz和1900MHz频段上的蜂窝电话系统采用此技术。 目前的电路交换GSM网以9.6Kbps的速率传送数据，利用多时间隙高速电路交换数据（HSCSD）的升级，速率可达43.2Kbps。GSM的3G对手——宽带码分多接入（WCDMA），能提供更高的数据速率。WCDMA能以高达2Mbps（本地接入）和384Kbps的速率（广域接入），支持移动的话音、图像、数据和视频通信。输入信号在一个频率范围内以编码的扩频方式，实现信号的数字化和传输。与窄带CDMA的200kHz宽的载波相比，它采用了5MHz宽的载波。 事实上，3G技术能等同地应用到现在正考虑采用的所有标准，包括美国的CDMA2000。CDMA2000能支持速度范围为144Kbps到2Mbps的移动数据通信。它现处于计划阶段。 在欧洲已非常流行的GPRS（基于GSM的分组无线电服务），目前在美国也正在推出。利用GPRS，数据流被分成数据分组，而不是GSM电路交换网络的连续流。分组化的GPRS提供“永远在线”的连接，而对于GSM，只要你占了信道不管你是否传送了数据和话音都要付钱。GPRS是承诺移动因特网功能的核心，以最高达115Kbps的速率向用户提供话音、视频和数据。在欧洲，预计到2002年初，具备GPRS功能的手机将进入大众市场。计算机英文翻译-VoiceXMLVoiceXML(2)Designing a speech application includes presenting data for delivery over the phone, constructing a call flow and enabling prompts and grammars. VoiceXML provides a common set of rules as a flexible foundation, but it’s up to the designer to create the appropriate flow and personality for a speech system.Just as HTML content is interpreted by a browser and presented visually over the Web, so must VoiceXML be understood or interpreted for presentation over the telephone by a speech, or voice, browser. The speech browser serves as a gateway between a call and an Internet connection. It interprets VoiceXML code and manages dialog between callers and VoiceXML content located at a Web site.Speech browser software also maintains the calls, presents voice prompts that equate to URLs and downloads pages for audio interaction. A VoiceXML-based application using a speech browser provides flexibility, benefiting callers and content providers alike. A caller could use a rotary telephone or the newest wireless model and receive the same service. Content providers have a choice of locating a speech browser at their facilities or outsourcing to an application service provider, carrier or service bureau. As with current visual Web models, trade-offs have to be weighed between ease of implementation, flexibility, cost and other factors. Today, companies are building businesses on speech-based Web content by providing telephony access and presentation of data in interactive audio formats. These businesses host speech applications to provide greater scalability, maintenance and support, while letting content providers focus on their core business. A number of obvious and subtle factors are converging to bring the Web model of VoiceXML to prominence. Many consider the broad industry support of VoiceXML its most apparent strength. Other factors such as recent improvements in text-to-speech quality mean information can be immediately presented in audio format without the time and expense of recording a voice. Looking at the evolution of the Web, it’s clear the adoption of a common format for content presentation——HTML——fueled the growth of the Web. The VoiceXML standard holds similar promise for speech. [参考译文]VoiceXML(2)设计语音应用程序包含了通过电话提交的数据表达、呼叫流程的建立以及提示和语法的实施。VoiceXML提供一个公共的规则集，作为灵活性的基础，但是建立恰当的语音系统的流程和个性取决于设计者。正如HTML的内容由浏览器解释并在Web网站上用可视的方式表达出来一样，VoiceXML也必须能由语音或声音浏览器理解或解释，以通过电话表达。语音浏览器起到了在呼叫和因特网连接之间的网关的作用。它解释VoiceXML的代码和管理呼叫者与某个网站上VoiceXML内容之间的对话。语音浏览器软件也维护呼叫，表达相当于URL的语音提示和为音频交互下载网页。利用语音浏览器，基于VoiceXML的应用程序提供了灵活性，有利于呼叫者和内容提供商双方。呼叫者可以老式的转盘拨号电话机或者最新的无线电话机，获得同样的服务。内容提供商可以选择将语音浏览器放在自己的设备上，或者外包给应用服务供应商（ASP）、电信运营商或服务公司。对于目前的可视Web模型，必须在易于实施、灵活性、成本和其他因素之间进行折衷考虑。今天，不少公司正在将业务建立在基于语音的网站内容上，提供电话访问和提供以交互的音频格式的数据表达。这些业务包括了语音应用程序后，提供了更大的伸缩性、更便于维护和支持，同时让内容提供商专心做其核心业务。很多显而易见的细微因素组合在一起，使VoiceXML网站模型浮出水面。很多人将业界对VoiceXML的广泛支持当做它最明显的优势。其他一些因素，如最近文本向语音转换的质量提高，意味着信息能马上以音频格式表达，没有了录音的开销和时间。回顾一下网站的发展，很清楚，正是采用了通用的内容表达方式——HTML，促进了网站的发展。VoiceXML标准有望为语音提供同样的前景这个网站上还有相关的~我就不一一贴着了~，你自己打开看啊
学术堂最新整理了十五个好写的计算机专业毕业论文题目,供大家参考:1、星连通圈网络和三角塔网络的若干性质研究2、中职《计算机应用基础》分层次教学研究3、基于MSP430单片机的电能质量检测仪设计4、光学遥感相机数据存储系统设计与实现5、基于单片机的级联型升压逆变器的设计及实现6、翻转课堂在职业学校《计算机应用基础》课程中的应用研究7、基于信息物理系统架构的微机接口远程实验系统设计与实现8、基于1553B总线的星务仿真系统设计9、曲面喷墨运动控制系统的研究10、项目教学法在中职计算机教学中的应用研究11、虚拟化在铁路数据中心的应用12、基于微信的学校学习支持服务的设计研究13、基于量化方法的高校师范生教学能力培养模式研究14、职业院校一体化课程教学模式研究15、应用于PowerPC处理器的乘法器设计与验证
计算机英语是学习计算机新理论和新技术的桥梁。计算机英语教材的主要目标是培养计算机及其相关专业学生使用本专业英语的能力。下面是我为大家整理的计算机英语论文，供大家参考。
计算机英语论文范文一：计算机英语教学实训设计研究
1高职高专计算机英语的特点
1.1时效性和实用性
新技术飞速发展，大量的计算机专业概念专业词汇随着新技术的发展层出不穷。如ITinformationtechnology;online;E-merce等都是随着新技术的发展产生和应用的，因此它的时效性和实用性显而易见。
1.2专业性与客观性
计算机专业文章一般重在客观地陈述事实，力求严谨和清清楚，避免主观成分和感 *** 彩，这就决定了计算机英语具有客观性。
1.3专业术语多
如：CPUCentralProcessingUnit：中央处理器;DBSMDatabaseSystem资料库管理系统OperatingSystem作业系统.
1.4缩略语经常出现
如：MBMotherBoard：主机板，LCDLiquidCrystalDisplay：液晶萤幕USBUniversalSerialBus：通行序列汇流排;
1.5合成的新词多
如：input出入;output输出;Personalputer：个人计算机;
1.6介词短语、分词短语和名词性片语和长句使用频繁
如：Someapplicationpackagesofferconsiderableputingpowerbyfocusingonasingletask，suchaswordprocessing;others，calledintegratedsoftwareoffersomewhatlesspowerbutincludeseveralapplications，suchasawordprocessor，aspreadsheet，andadatabaseprogram.有些应用程式包可就一个单项任务提供相当的计算能力，如文书处理;其它应用程式包，称为综合软体，计算能力略差但也包括了很多应用功能，如：文书处理器，电子表格和资料库程式等。
2如何开展高职高专计算机英语教学和实训
“加快现代职业教育体系建设，深化产教融合、校企合作，培养数以亿计的高素质劳动者和技术技能人才。”是发展职业教育的指导思想。高职高专IT职业英语的任务就是要培养既有一定IT专业技术技能，又有较强的外语水平的高素质人才。
2.1合理的课程安排
高职高专《计算机英语》主要针对高职院校的计算机各专业学生开设，是计算机专业学生学好计算机专业课程的一门重要工具。为软体技术，资讯管理，物联网技术，等专业方向的学生必修课。
2.2实用的高职高专计算机英语实训内容
通过计算机英语教学内容的学习，使学生掌握电脑科学相关硬体和软体以及相关计算机技术的英语表达方式，并运用到实践中。在实训时，学生应能够运用所学的计算机英语知识，根据看到的硬体装置实现口头表达，以及借助相关工具书和翻译软体，对与自己专业相关文献和应用软体，实现书面表达。了解上机时常见的提示资讯及解释，根据专业方向能看懂与本专业相关的专业资讯提示。通过本课程实训使学生扫清上机时使用英语软体的障碍，并且使学生具备阅读计算机专业英语书刊的能力，能听懂一般性专业学术报告的能力。
2.3基于专业需求的课程和实训设计
1基于专业需求的课程和实训设计设计理念计算机英语程开发遵循“劳动过程系统化”的先进教学理念，贯穿日常教学中，将理论教学中渗入实训教学环节，提出集专案确定——专案分析——专案策划——专案管理与评估为一体的系统的实训教学模式，以专案驱动来完成知识的内化。在软体技术专业可以侧重SoftwareEngineer的教学与实训设计;网路工程专业则可以加强puterNetworks的教学与实训设计;而资讯管理专业应侧重DatabaseSystem的教学与实训设计。
2基于专业需求的课程和实训设计设计思路计算机英语课程和实训设计的总体思路是：以市场为导向，基于IT行业人员工作岗位基本职责进行教学和实训设计，紧紧围绕各专业人才培养方案实施教学和实训，取舍教材内容，为专业服务。
3基于专业需求的课程和实训设计培养目标根据高职教育的指导思想和培养目标，在更新教学理念和创新教学模式的过程中，计算机英语课程和实训设计，以促进就业为导向，适应技术进步和生产方式变革以及社会公共服务的需要社会需求为出发点，以“实用为主，够用为度”为原则，突出专业特点，突出课程的实用性，适应计算机相应专业需求的，培养具有动手能力和创新意识的高技术人才。计算机英语是一门实用时很强的课程，要求教师具有较强的英语语言知识与应用能力，同时要具备对科技前沿的洞察力，更需要更新教学理念，创新教学模式，注重实训环节。
计算机英语论文范文二：计算机英语课内实践教学研究
1.课内实践教学多元化
1.1“任务驱动”教学方式
对于该课程,课内实践教学的目的是为了充分发挥教师的主导作用和学生的主体作用,因此,采用“任务驱动”的方式可以较好的激发学生的积极性。“任务驱动”指的是学生在学习过程中,在教师的帮助下,围绕一个共同的任务为中心来完成,在这个过程中,学生会通过任务的程序获得成就感,可以较大地激发他们的积极性,逐步形成一个良性回圈,从而培养学生独立思考和自主学习能力。该门课内实践教学结合任务驱动的方式,已经采用的是让学生选择自己感兴趣的某个IT领域技术方向,运用文献检索方法,自行查询英文文献并阅读翻译,在课堂上用英文对其作报告,并制作英文PPT加以展示,并新增现场提问的环节,培养学生用英文进行学术答辩的能力。通过在课堂上使用这种实践方式,已取得了较好的效果。
1.2其他多元化的任务方式
除了培养学生英文文献检索、学术报告的能力之外,应用型本科IT专业学生是未来IT行业的建设者之一,该课内实践教学还要考虑市场需求的因素。在IT行业中,企业对员工专业英语能力的需求是必要且多样化的;如测试、编码等初级职位员工只需要阅读使用者介面、操作说明等英文文献的能力;而对于技术研究等中级职位,不仅需要阅读能力还要求掌握一定的翻译技能、回复英文邮件等;在更高级别的工作如订单签订、专案谈判等事务中,则需要具备听、说、读、写、译各方面的综合能力以及跨文化交流能力。因此在今后的实践教学中,计划新增多样的任务方式,如设计一些具有很强实践性和实操性的活动,全方位训练和提高学生面向行业、企业岗位需求、在真实工作环境中的英语交际能力、应用能力和学习能力。比如训练学生英文简历的撰写,再设计情景对话,让学生分小组扮演IT公司面试官和应聘者角色,对职场招聘进行场景模拟,学习和应用计算机英语知识和口语表达能力。不仅如此,在工程实践中,软体企业开发人员常常需要编写英文版本的软体需求文件和使用者指南,因此还可以考虑与软体工程的课程老师合作,在学生进行课程设计时编写英文版本的软体需求规格说明书。
1.3灵活布置作业
作业也是实践教学的重要补充,对于作业一定要布置一些实用有意义的内容,这样学生才会主动而非被迫地去做;关于这方面教师要充分利用自己积累的学习和工作经历。比如根据笔者学生时期的应聘经验,可以告诉学生大中型IT公司的软体开发职位招聘的笔试题很重视动态记忆体方面的内容,有相当比例该方面的试题,也具有一定难度,而很多中文教材关于此方面的内容往往讲解的不够详实,而英文教材文献六的“PointersandDynamicMemory”这一节对动态记忆体的思想介绍的较清晰,通过此类方法抓住学生的心理,吸引学生主动地去学习,这样不仅训练了计算机英语,又提升了学生应聘的竞争力。此外,一定要让学生体会到利用网路资源来促进学习和交流的重要性。可以鼓励学生登陆各大著名IT外企的网站,上面会经常地提供其新技术和新产品宣传的英文视讯和动画。这类视讯短片直观而形象,学生不但学习了新技术和新词汇,同时还锻炼了听说能力,学习兴趣也会大大提高。还可以引导学生平时多关注外企网站上的招聘广告,本专业领域的产品说明书等,上面有大量描述本专业技术的计算机英语,这对培养学生的实际应用能力有很大的帮助。
2结语
该文分析了计算机英语课内实践教学对于IT应用型人才培养的必要性,并结合该研究者本身的经验体会,探讨了一些关于该课程的课内实践教学方式,通过在教学实践中使用这些方式,已取得了较好的效果。计算机英语是专业课和英语课的有机结合,具有很强的实用性。课内实践教学应合理采用多种有效的教学方法和多元化教学模式,让学生通过该课程的学习,进一步提高专业英语听、说、读、写等水平,培养综合素质,从而提高了就业竞争力,才能真正发挥该课程的作用。
提供一些英语专业的毕业论文题目，供参考。
题目不要太大，也不要太小，太大了面太广容易泛泛，小了就无材料可查，没东西可写。写你熟悉的 资料好查的 参考
电脑，在日常生活，越来越普遍了。下面给大家分享一些关于电脑的 英语 作文 ，希望对大家有帮助。
关于电脑的英语作文1
Dear Editor,
I’m writing to tell you how us use computers in our daily lives.Most of us use computers to search for more information about the interesting problems on the textbooks, about Iraqi wars and about Oscar. Some of us use computers to do some drawings, to make up interesting flashes. And some of us use them to play games. If we are tired and want to take a short rest, playing games for a while is OK. But it’s forbidden that we spend hours and hours on the games. There is also someone using computers to talk with people in the Internet and even falling in love with him or her. The Internet is not a real world and we can’t tell lies from truths. So falling in love with somebody on the Internet is not safe and is bad for our study. We should keep ourselves out of it.That’s all I know.Good luck!
Yours truly,
Li Hua
关于电脑的英语作文2
Computer is a very useful machine. Some of them are big, but some of them are very small .Many people like playing computer. Computer has many functions, so that people can do a lot of things by computer, like watching movies, listening to the music or playing games. It can make our lives very colorful and convenient. Various people can make good use of computer. Children can use computer to learn and play games. Parents can use computers to work. I think computer is a kind of wonderful and interesting machine, so I like computer very much.
关于电脑的英语作文3
When I was in grade four in primary school, my father taught me how to use computer. After that, I was very interested in playing computer. I watched movies, played computer games, searched the Internet and listened to the music on computer. Because my father must work in his computer, so he bought another for me. I was very happy that I had my own computer. It was put in the study. I am always very careful to use my computer, because I am worried I would break. I often chat with my net friends. Because of my computer, I make many friends who have many in common. Of course, I use my computer in study. There are resources on the Internet. I can learn more after class. It does great help to me.
关于电脑的英语作文4
Computer is increasingly popular in people’s daily life. The number of computer in every family is more than TV set. Some people think it is so great that they all regard it as a gift from the heaven. However, some people consider it brings more disadvantages than advantages. In my opinion, both opinions are correct, but if we can use computer in a proper way, its advantages are superior to disadvantages. I have several reasons.
On the one hand, computer makes human beings’ life become easier. People can do many things that they can’t do before. They can read newspaper without buying it, only sitting in front of their computer, clicking mouse to open website. Shopping online, watching movies, listening music and play computer games are the common things that people often do by computer. But without computer, they can’t do all these easily. In addition, computer is also very helpful for study and work. People can have classes and work on it.
On the other hand, computer has so many attractive things that some people will be addicted to it. Some of them may busy finding funs on it, and then ignore their real duty, such as, study and work. As a result, it will have great bad effect on their future.
To sum, computer has advantages and disadvantages. But if people can control themselves to use computer properly, it is useful for their whole life.
关于电脑的英语作文5
With the rapid process of modernization, computer becomes more and more popular. Nowadays, almost every family has a computer. Because of computers, our daily life is improving.
Computer has a great effect on our daily life. In the first place, computer has so many functions. As we have computers, we needn't buy books, radios, TVs and any other things, because computer can take place of them. Secondly, surfing on the Internet must be very interesting. Through the Internet, we can do everything we like. Thirdly, thanks to the Internet, we can get the further education at any time, so we don't have to get up so early in winter days.
However, a coin has two sides, because it's new doesn't mean it's always good. At present, most students spend too much time on computer games. I don't think it's a good phenomenon, because it will do great harm to our eyes as well as our health if we play computer games all the time.
In my opinion, we should use the computers in the right way. For instance, we can read the latest news on the internet to know the world better; read the e-books to enrich our knowledge or download some useful information for our work. We can also make different friends on the Internet, so that our life will be colorful. I believe computers will be our best friends if we make good use of them.
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电脑的学名为电子计算机，是由早期的电动计算器发展而来的。1946年，世界上出现了第一台电子数字计算机“ENIAC”，用于计算弹道。是由美国宾夕法尼亚大学莫尔电工学院制造的，但它的体积庞大，占地面积170多平方米，重量约30吨，消耗近100千瓦的电力。显然，这样的计算机成本很高，使用不便。1956年，晶体管电子计算机诞生了，这是第二代电子计算机。只要几个大一点的柜子就可将它容下，运算速度也大大地提高了。1959年出现的是第三代集成电路计算机。最初的计算机由约翰·冯·诺依曼发明(那时电脑的计算能力相当于现在的计算器)，有三间库房那么大，后逐步发展。 从20世纪70年代开始，这是电脑发展的最新阶段。到1970年，由大规模集成电路和超大规模集成电路制成的“克雷一号”，使电脑进入了第四代。超大规模集成电路的发明，使电子计算机不断向着 小型化、微型化、低功耗、智能化、系统化的方向更新换代。20世纪90年代，电脑向“智能”方向发展，制造出与人脑相似的电脑，可以进行思维、学习、记忆、网络通信等工作。 进入21世纪，电脑更是笔记本化、微型化和专业化，每秒运算速度超过100万次，不但操作简易、价格便宜，而且可以代替人们的部分脑力劳动，甚至在某些方面扩展了人的智能。于是，今天的微型电子计算机就被形象地称做电脑了。世界上第一台个人电脑由IBM于1981年推出。IBM推出以英特尔的x86为硬体架构，以微软公司的MS-DOS为操作系统的个人电脑，并制定以PC/AT为PC的规格。之后，由英特尔推出的微处理器以及微软推出的操作系统的发展几乎等同于个人电脑的发展历史。Wintel架构全面取代了IBM在个人电脑世界的主导地位。 通常说到“世界公认的第一台电子数字计算机”大多数人都认为是1946年面世的“ENIAC”，它主要是用于计算弹道。是由美国宾夕法尼亚大学莫尔电气工程学院制造的，它的体积庞大，占地面积170多平方米，重量约30吨，消耗近150千瓦的电力。显然，这样的计算机成本很高，使用不便。这个说法被计算机基础教科书上普遍采用,事实上在1973年根据美国最高法院的裁定,最早的电子数字计算机,应该是美国爱荷华州立大学的物理系副教授约翰·阿坦那索夫和其研究生助手克利夫·贝瑞(Clifford E. Berry ，1918-1963）于1939年10月制造的"ABC"(Atanasoff- Berry-Computer）。之所以会有这样的误会，是因为“ENIAC”的研究小组中的一个叫莫克利的人于1941年剽窃了约翰·阿坦那索夫的研究成果，并在1946年时，申请了专利。由于种种原因直到1973年这个错误才被扭转过来。（具体情况参阅百度百科----“约翰·阿坦那索夫”词条，希望大家记住ABC和约翰·阿坦那索夫，希望以后的教科书能够修改这个错误）。后来为了表彰和纪念约翰·阿坦那索夫在计算机领域内作出的伟大贡献，1990年美国前总统布什授予约翰·阿坦那索夫全美最高科技奖项----“国家科技奖”。 中国电脑 中国的算盘是最早的运算工具。在人类文明发展的历史上中国曾经在早期计算工具的发明创造方面写过光辉的一页。远在商代，中国就创造了十进制记数方法，领先于世界千余年。到了周代，发明了当时最先进的计算工具——算筹。这是一种用竹、木或骨制成的颜色不同的小棍。计算每一个数学问题时，通常编出一套歌诀形式的算法，一边计算，一边不断地重新布棍。中国古代数学家祖冲之，就是用算筹计算出圆周率在3.1415926和3.1415927之间。这一结果比西方早一千年。 珠算盘是中国的又一独创，也是计算工具发展史上的第一项重大发明。这种轻巧灵活、携带方便、与人民生活关系密切的计算工具，最初大约出现于汉朝，到元朝时渐趋成熟。珠算盘不仅对中国经济的发展起过有益的作用，而且传到日本、朝鲜、东南亚等地区，经受了历史的考验，至今仍在使用。 中国发明创造指南车、水运浑象仪、记里鼓车、提花机等，不仅对自动控制机械的发展有卓越的贡献，而且对计算工具的演进产生了直接或间接的影响。例如，张衡制作的水运浑象仪，可以自动地与地球运转同步，后经唐、宋两代的改进，遂成为世界上最早的天文钟。 记里鼓车则是世界上最早的自动计数装置。提花机原理与计算机程序控制的发展有过间接的影响。中国古代用阳、阴两爻构成八卦，也对计算技术的发展有过直接的影响。莱布尼兹写过研究八卦的论文，系统地提出了二进制算术运算法则。他认为，世界上最早的二进制表示法就是中国的八卦。 经过漫长的沉寂，新中国成立后，中国计算技术迈入了新的发展时期，先后建立了研究机构，在高等院校建立了计算技术与装置专业和计算数学专业，并且着手创建中国计算机制造业。 中国是在1956年研制成功国产计算机的。1958年和1959年中国先后自主研制成功国产小型和大型电子管计算机。60年代中期，中国研制成功一批晶体管计算机，并配制了ALGOL等语言的编译程序和其他系统软件。60年代后期，中国开始研究集成电路计算机。70年代，中国已批量生产小型集成电路计算机。80年代以后，中国开始重点研制微型计算机系统并推广应用；在大型计算机、特别是巨型计算机技术方面也取得了重要进展；建立了计算机服务业，逐步健全了计算机产业结构。 在计算机科学与技术的研究方面，中国在有限元计算方法、数学定理的机器证明、汉字信息处理、计算机系统结构和软件等方面都有所建树。在计算机应用方面，中国在科学计算与工程设计领域取得了显著成就。在有关经营管理和过程控制等方面，计算机应用研究和实践也日益活跃。The scientific name for electronic computer by early computer, is developed from electric calculator. In 1946, the world appeared the first electronic digital computer "ENIAC", used for calculating trajectory. By the university of Pennsylvania electrician college manufacturing, Moore, the huge volume, but it occupies an area of more than one hundred seventy square meters, weight is about 30 tons, consumption by nearly 100 kilowatts of electricity. Obviously, this computer cost is high, difficult to use. In 1956, transistor electronic computer was born, this is the second generation of computers. Only a few bigger cabinet can will it hold, speed also greatly increased. 1959 appeared in the third generation integrated circuit computer. Early computer by John and von neumann invention (then the computing power of computer now, there are three calculators) is so large, warehouse after between gradual development. From 20th century since the 1970s, this is the latest stage of computer development. To 1970, by large scale integrated circuit and vlsi circuits made of "no.1", make the computer clay into the fourth generation. The invention of vlsi, make the electronic computer constantly toward miniaturization, miniaturization, low power consumption, intelligent, systematic direction upgraded. During the 1990s, the computer to "smart" direction development, produce and the brain computer, can undertake similar thinking, learning and memory, network communication, etc. Entering the 21st century, the computer is notebook change, miniaturization and specialization, gigabits per second operation speed over 100 million times, not only operate simple, cheap, and can replace people part mental work, even in some ways expanded the human's intelligence. So, today's microcomputer is what has been aptly called computer. The world's first personal computers launched by IBM in 1981. Introduction to Intel's x86 IBM for hardware structure, with Microsoft's ms-dos for the personal computer operating system and formulated to PC/AT for PC specification. Later, launched by Intel microprocessor and Microsoft introduced the development of the operating system almost as fast as the development history of personal computers. Wintel architecture comprehensive replaced in the PC world of IBM's dominance. Usually said "the world recognized as the first electronic digital computer" most people think that is available in 1946, "it" ENIAC is mainly used for calculating trajectory. By the university of Pennsylvania is made of electrical engineering college Mohr, its huge volume, covers an area of more than one hundred seventy square meters, weight is about 30 tons, costs nearly 150 kilowatts of electricity. Obviously, this computer cost is high, difficult to use. This statement is widely used Computer basic textbooks in 1973, in fact, according to the United States Supreme Court ruled that the earliest digital electronic computers, should is the Iowa state university physics department associate professor John o SuoFu and its Tampa that graduate assistant cliff Berry (Clifford Berry e., 1918-1963) in October 1939 manufacturing "ABC" (Atanasoff - Berry - Computer). Have this misunderstanding, because "ENIAC" one of the research team at Cleveland, called mo 1941, o John plagiarism SuoFu research achievements of the Tampa in 1946, and apply for a patent. Due to various reasons until 1973 this error is turn them around. (particular case refer to baidu - "John o wikipedia entries and SuoFu" Tampa that hope everyone remember ABC and John o SuoFu, hoped later tantra that can modify this error of textbook. Later in order to commend and commemorative John o SuoFu in computer field tantra it within a great contribution in 1990, former U.S. President bush awarded Tampa SuoFu John o across the highest technology awards - "the state" eeffect ".Chinese computer Chinese abacus is the earliest computing tools. In the history of the development of human civilization in China was once early computing tools invention aspects wrote a glorious page. Shang, China will have created a decimal numeration method, leading in more than 1,000 years. To the zhou dynasty, invented the most advanced computing tools - count chips. This is a kind of bamboo, wood or bone of different colors made of small stick. Computing every math problems, usually make up a set of GeJue forms of algorithm, side calculation, side constantly to cloth stick. Ancient Chinese mathematician zu chongzhi, is calculated by numerical raised in 3.1415927 3.1415926 and between of PI. The results earlier than the west for a thousand years. Abacus plate is another original Chinese, but also in the history of computing tools in the first major inventions. This light and flexible, convenient to carry, and people's living close calculation tool, first emerged when YuHanChao maturity, to the yuan dynasty. Abacus in Chinese economy not only dish played beneficial effects of the development, and spread to Japan, Korea, southeast Asia and other regions, withstand the test of the history, are still in use. Chinese inventions, it was the direction-guiding cart in waterway written instrument, such as car, jacquard machine drums, not only to the development of automatic control machines have outstanding contributions to computing tools, and the evolution produced direct or indirect impact. For example, it was made of zhang heng waterway, can automatically instrument with earth in moving synchronization, by the tang, song after two generations of improvement, thus became the world's first world. The car is written in the world drum, the earliest automatic counting device. Jacquard machine principle and the development of the computer program control have indirect effects. Ancient Chinese Yao with Yang, Yin constitutes a gossip, and two of the development of computing technology have direct influence. Leibnitz wrote research papers, systematically tabloid forward binary arithmetic algorithms. He thinks, the world's first binary representation is China's gossip. After a long silence, after the founding of new China, Chinese computing entered the new developing period, has established a research organization, in universities and colleges to establish computing technology and device professional and computational mathematics, and hands to create China professional computer manufacturing. China is developed successfully in 1956 in home computer. In 1958 and 1959 China has successfully developed independently domestic small and large tube computer. In the mid 60, China has successfully developed computer, and configuration of the transistor such language ALGOL compiler and other system software. In the late 1960's, China began to study computer integrated circuits. In the 1970s, China has batch production small integrated circuit computer. In the 1980s, China began after key development microcomputer system and popularized; In large computer, especially huge computer technology has also made important progress; Established computer services, and gradually improve the computer industry structure. In computer science and technology research, China in finite element calculation method, mathematical theorems machine proof, Chinese information processing, computer system structure and software all aspects contribute. In computer applications, in Chinese scientific computing and engineering design fields have achieved remarkable success. In the related management and process control, computer application research and practice is increasingly active.
Computer has become a major source of access to knowledge. By computer on the Internet we can see the latest, fastest and most authoritative news, you can not learn in books of knowledge, know the unknown information more widely, also make more students faster, earlier and closer to science and technology front, it helps us to love science, advocating science. Computer is a useful tool to enhance communication. Computer Internet chat rooms or we can OICQ chat and other communication sites in this virtual world, each talking about their favorite subject, users young or old, regardless of occupation, as long as the similar interests that can pour out their feelings. This desire for friends, friendship, desire, desire to talk to us it is a great opportunity. We are happy to talk about in the network, relax and be spiritually free.
这个太难搞了！
计算机英语是学习计算机新理论和新技术的桥梁。计算机英语教材的主要目标是培养计算机及其相关专业学生使用本专业英语的能力。下面是我为大家整理的计算机英语论文，供大家参考。
计算机英语论文范文一：计算机英语教学实训设计研究
1高职高专计算机英语的特点
1.1时效性和实用性
新技术飞速发展，大量的计算机专业概念专业词汇随着新技术的发展层出不穷。如ITinformationtechnology;online;E-merce等都是随着新技术的发展产生和应用的，因此它的时效性和实用性显而易见。
1.2专业性与客观性
计算机专业文章一般重在客观地陈述事实，力求严谨和清清楚，避免主观成分和感 *** 彩，这就决定了计算机英语具有客观性。
1.3专业术语多
如：CPUCentralProcessingUnit：中央处理器;DBSMDatabaseSystem资料库管理系统OperatingSystem作业系统.
1.4缩略语经常出现
如：MBMotherBoard：主机板，LCDLiquidCrystalDisplay：液晶萤幕USBUniversalSerialBus：通行序列汇流排;
1.5合成的新词多
如：input出入;output输出;Personalputer：个人计算机;
1.6介词短语、分词短语和名词性片语和长句使用频繁
如：Someapplicationpackagesofferconsiderableputingpowerbyfocusingonasingletask，suchaswordprocessing;others，calledintegratedsoftwareoffersomewhatlesspowerbutincludeseveralapplications，suchasawordprocessor，aspreadsheet，andadatabaseprogram.有些应用程式包可就一个单项任务提供相当的计算能力，如文书处理;其它应用程式包，称为综合软体，计算能力略差但也包括了很多应用功能，如：文书处理器，电子表格和资料库程式等。
2如何开展高职高专计算机英语教学和实训
“加快现代职业教育体系建设，深化产教融合、校企合作，培养数以亿计的高素质劳动者和技术技能人才。”是发展职业教育的指导思想。高职高专IT职业英语的任务就是要培养既有一定IT专业技术技能，又有较强的外语水平的高素质人才。
2.1合理的课程安排
高职高专《计算机英语》主要针对高职院校的计算机各专业学生开设，是计算机专业学生学好计算机专业课程的一门重要工具。为软体技术，资讯管理，物联网技术，等专业方向的学生必修课。
2.2实用的高职高专计算机英语实训内容
通过计算机英语教学内容的学习，使学生掌握电脑科学相关硬体和软体以及相关计算机技术的英语表达方式，并运用到实践中。在实训时，学生应能够运用所学的计算机英语知识，根据看到的硬体装置实现口头表达，以及借助相关工具书和翻译软体，对与自己专业相关文献和应用软体，实现书面表达。了解上机时常见的提示资讯及解释，根据专业方向能看懂与本专业相关的专业资讯提示。通过本课程实训使学生扫清上机时使用英语软体的障碍，并且使学生具备阅读计算机专业英语书刊的能力，能听懂一般性专业学术报告的能力。
2.3基于专业需求的课程和实训设计
1基于专业需求的课程和实训设计设计理念计算机英语程开发遵循“劳动过程系统化”的先进教学理念，贯穿日常教学中，将理论教学中渗入实训教学环节，提出集专案确定——专案分析——专案策划——专案管理与评估为一体的系统的实训教学模式，以专案驱动来完成知识的内化。在软体技术专业可以侧重SoftwareEngineer的教学与实训设计;网路工程专业则可以加强puterNetworks的教学与实训设计;而资讯管理专业应侧重DatabaseSystem的教学与实训设计。
2基于专业需求的课程和实训设计设计思路计算机英语课程和实训设计的总体思路是：以市场为导向，基于IT行业人员工作岗位基本职责进行教学和实训设计，紧紧围绕各专业人才培养方案实施教学和实训，取舍教材内容，为专业服务。
3基于专业需求的课程和实训设计培养目标根据高职教育的指导思想和培养目标，在更新教学理念和创新教学模式的过程中，计算机英语课程和实训设计，以促进就业为导向，适应技术进步和生产方式变革以及社会公共服务的需要社会需求为出发点，以“实用为主，够用为度”为原则，突出专业特点，突出课程的实用性，适应计算机相应专业需求的，培养具有动手能力和创新意识的高技术人才。计算机英语是一门实用时很强的课程，要求教师具有较强的英语语言知识与应用能力，同时要具备对科技前沿的洞察力，更需要更新教学理念，创新教学模式，注重实训环节。
计算机英语论文范文二：计算机英语课内实践教学研究
1.课内实践教学多元化
1.1“任务驱动”教学方式
对于该课程,课内实践教学的目的是为了充分发挥教师的主导作用和学生的主体作用,因此,采用“任务驱动”的方式可以较好的激发学生的积极性。“任务驱动”指的是学生在学习过程中,在教师的帮助下,围绕一个共同的任务为中心来完成,在这个过程中,学生会通过任务的程序获得成就感,可以较大地激发他们的积极性,逐步形成一个良性回圈,从而培养学生独立思考和自主学习能力。该门课内实践教学结合任务驱动的方式,已经采用的是让学生选择自己感兴趣的某个IT领域技术方向,运用文献检索方法,自行查询英文文献并阅读翻译,在课堂上用英文对其作报告,并制作英文PPT加以展示,并新增现场提问的环节,培养学生用英文进行学术答辩的能力。通过在课堂上使用这种实践方式,已取得了较好的效果。
1.2其他多元化的任务方式
除了培养学生英文文献检索、学术报告的能力之外,应用型本科IT专业学生是未来IT行业的建设者之一,该课内实践教学还要考虑市场需求的因素。在IT行业中,企业对员工专业英语能力的需求是必要且多样化的;如测试、编码等初级职位员工只需要阅读使用者介面、操作说明等英文文献的能力;而对于技术研究等中级职位,不仅需要阅读能力还要求掌握一定的翻译技能、回复英文邮件等;在更高级别的工作如订单签订、专案谈判等事务中,则需要具备听、说、读、写、译各方面的综合能力以及跨文化交流能力。因此在今后的实践教学中,计划新增多样的任务方式,如设计一些具有很强实践性和实操性的活动,全方位训练和提高学生面向行业、企业岗位需求、在真实工作环境中的英语交际能力、应用能力和学习能力。比如训练学生英文简历的撰写,再设计情景对话,让学生分小组扮演IT公司面试官和应聘者角色,对职场招聘进行场景模拟,学习和应用计算机英语知识和口语表达能力。不仅如此,在工程实践中,软体企业开发人员常常需要编写英文版本的软体需求文件和使用者指南,因此还可以考虑与软体工程的课程老师合作,在学生进行课程设计时编写英文版本的软体需求规格说明书。
1.3灵活布置作业
作业也是实践教学的重要补充,对于作业一定要布置一些实用有意义的内容,这样学生才会主动而非被迫地去做;关于这方面教师要充分利用自己积累的学习和工作经历。比如根据笔者学生时期的应聘经验,可以告诉学生大中型IT公司的软体开发职位招聘的笔试题很重视动态记忆体方面的内容,有相当比例该方面的试题,也具有一定难度,而很多中文教材关于此方面的内容往往讲解的不够详实,而英文教材文献六的“PointersandDynamicMemory”这一节对动态记忆体的思想介绍的较清晰,通过此类方法抓住学生的心理,吸引学生主动地去学习,这样不仅训练了计算机英语,又提升了学生应聘的竞争力。此外,一定要让学生体会到利用网路资源来促进学习和交流的重要性。可以鼓励学生登陆各大著名IT外企的网站,上面会经常地提供其新技术和新产品宣传的英文视讯和动画。这类视讯短片直观而形象,学生不但学习了新技术和新词汇,同时还锻炼了听说能力,学习兴趣也会大大提高。还可以引导学生平时多关注外企网站上的招聘广告,本专业领域的产品说明书等,上面有大量描述本专业技术的计算机英语,这对培养学生的实际应用能力有很大的帮助。
2结语
该文分析了计算机英语课内实践教学对于IT应用型人才培养的必要性,并结合该研究者本身的经验体会,探讨了一些关于该课程的课内实践教学方式,通过在教学实践中使用这些方式,已取得了较好的效果。计算机英语是专业课和英语课的有机结合,具有很强的实用性。课内实践教学应合理采用多种有效的教学方法和多元化教学模式,让学生通过该课程的学习,进一步提高专业英语听、说、读、写等水平,培养综合素质,从而提高了就业竞争力,才能真正发挥该课程的作用。
Information literacy Knowing how to find data from several sources, select relevant material, analyse and organise it into a form that can be used to make decisions. Computers have become the tools people use to access and manage information. Information technologists are people who analyse and design the tools. What is a computer? Tradition definitions of computers include �6�1 A machine that accepts data and processes it into use information. �6�1 A computer is a binary, digital, electronic, stored program machine. �6�1 While a computer is commonly a digital machine, analogue machine do exist. An electronic device, operating under the control of instructions stored in its own memory unit, that can accept data (input), process data arithmetically and logically, produce results (output) from the processing and stores results for future use. Many computers receive and send data (communicate) across networks LAN and Wan. A computer system consists of hardware and software. What is hardware? Hardware Hardware is physical devices or components that can be physically handled – you can thou it. Input Devices Input devices convert data that humans collect into coded electrical signals that a computer can process. The central processing unit The electronic processing takes place in the CPU. The CPU consists of �6�1 A control unit that controls all of the computer’s functions and an �6�1 Arithmetic and logical unit (ALU) that performs any calculation Memory Memory holds all programs and What is RAM currently open? Data (notes) Word processor O.S Output devices Output devices convert the computer’s electronic signals back into information Secondary storage devices These devices store programs and data permanently. The programs and data are not necessarily (or likely to be) in current use. E.g. DVD CD Communication devices These devices enable a computer to connect to another computer. List the six different type of hardware? Secondary storage(external), input, processor, output , memory, Communication. Name eight pieces of hardware USB, keyboard, monitor, screen, RAM, ROM, VDU, Modem. The system unit and peripheral devices The system unit is the computer box. Peripheral devices are any devices around the outside, or in other words, plugged into the (back of) the machine. Peripheral devices include the key board, mouse, printer, joy stick and others. Peripheral devices are any devices around the outside, or in other words, plugged into the (back of) the machine. Peripheral devices include the keyboard, mouse, printer, joy stick and others. What else does a computer have? Software Software is a computer program ,which is a detailed set of instructions that directs a computer to perform the tasks necessary to process data into information. These instructions are written in languages that computer can interpret. Software includes computer games, a word processing packing, an accounting package, amongst Definition of a computer system �6�1 A computer system is the configuration of hardware and software, functioning together, to process data into useful information, in order to achieve a purpose for a human user. What is data? �6�1 Data is raw facts, be they numbers, words, images and sounds, that can be input into a computer. e.g. Mary a name is a piece of data What is information? �6�1 Information is processed data, that has meaning and is useful. e.g. John is a list of names who scored an A grade on an exam John A Chai A Pam A e.g. Commodore $23 500 Magna $21 500 Falcon $19 800 The system unit contains the �6�1 Motherboard �6�1 CPU �6�1 Memory �6�1 Other electronics It is where the computer program instructions are executed and the data is manipulatedThe Processor CPU The CPU interprets and carries out basic instructions that operate the computer, the CPU contain the �6�1 Control unit and the �6�1 Arithmetic logic unit Control unit The control unit directs and coordinates the computer’s operations. For every single instruction, the control unit repeats four basic operations, �6�1 Fetching �6�1 Decoding �6�1 Executing �6�1 Storing CPU speed The CPU’s speed may be measured in MIPS The number of millions of instructions per second Arithmetic/logic unit The ALU performs all calculations, which involve �6�1 Arithmetic operations 2+3 �6�1 Comparison operations age>=17 �6�1 Logical operations pass Processing instructions A CPU may begin executing a second machine cycle before completing the first-referred to as pipelining. Current CPU’s can pipeline up to 4 instructions. Storage within the CPU Registers temporarily hold data and instructions. The computer’s clock A System clock is necessary to control the timing of all computer operations. Each tick of the clock is referred to as a clock cycle. Clock speed is the speed at which a processor executes instructions. A hertz is one cycle per second and a megahertz is 1024 by1024 and a gigahertz is 1024 by 1024 by1024. Memory Memory is the temporary storage place for data and (program) instructions. Memory is measured in �6�1 Kilobytes 1024 bytes 2^10 �6�1 Megabytes 1024* 1024 bytes 2^20 �6�1 Gigabytes 1024*1024*1024 bytes 2^30 Representation of data Digital computers are built from many small electronic circuits. Each circuit, at any point of time can be turned OFF or ON. Hence these devices are called two state devices. Binary Digit 0and 1 Each off or on digital value is called a bit, short for binary digit. A 1 bit computer would be able to distinguish between two values-characters, symbols or numbers. Hardly sufficient for the characters on the keyboard Bits Characters 1 2 2 4 3 8 4 16 5 32 6 64 7 128 8 256
题目：计算机是现代科学技术最杰出的成果之一，它无处不在，与我们生活的各个领域息息相关，Computers(电脑)。 请以“Computers”为题，写一篇100个单词左右的英语小短文。 要求写出计算机的具体用途和人们对于计算机应用的态度。 【范文】 Computers One of the greatest advancements in modern technology has been the invention of computers. Computers are changing the way people live and work. They are already widely used in industry, business and in academic institutions. With the popularization of science and technology, computers have found an increasingly wide application in all fields. A computer can do a lot of work. It is capable of doing extremely complicated work in all fields of learning. It can solve the most complex mathematics problems. Computers are able to store large amounts of information, which can be recalled rapidly at any time. The truth of the matter, however, is that any new technology has a “dark”side. The problems caused by the use of computers are quite different. For example, assembly lines will be a slow process to retain workers to build and operate new equipment. Nevertheless, the dark side of the computer shouldn't mean that we should abandon the use of computers. Technology only can make the real work cheaper, faster, and less tedious. It cannot solve problems. 【评语】 该文从现代化的'技术革新角度来谈计算机，然后在第二段里讲到，随着科学和技术的普遍应用，计算机也大放光彩，具体的例举了两个用处，高中英语写作《Computers(电脑)》。最后一段里，用“the truth of the matter”，再加“however”转折，说明了计算机的“dark side”，文章全面而重点突出。
What Is Grid Storage? Based on current and proposed products, it appears that a grid storage system should include the following: Modular storage arrays: These systems are connected across a storage network using serial ATA disks. The systems can be block-oriented storage arrays or network-attached storage gateways and servers. Common virtualization layer: Storage must be organized as a single logical pool of resources available to users. Data redundancy and availability: Multiple copies of data should exist across nodes in the grid, creating redundant data access and availability in case of a component failure. Common management: A single level of management across all nodes should cover the areas of data security, mobility and migration, capacity on demand, and provisioning. Simplified platform/management architecture: Because common management is so important, the tasks involved in administration should be organized in modular fashion, allowing the autodiscovery of new nodes in the grid and automating volume and file management. Three Basic Benefits Applying grid topology to a storage network provides several benefits, including the following: Reliability. A well-designed grid network is extremely resilient. Rather than providing just two paths between any two nodes, the grid offers multiple paths between each storage node. This makes it easy to service and replace components in case of failure, with minimal impact on system availability or downtime. Performance. The same factors that lead to reliability also can improve performance. Not requiring a centralized switch with many ports eliminates a potential performance bottleneck, and applying load-balancing techniques to the multiple paths available offers consistent performance for the entire network. Scalability. It’s easy to expand a grid network using inexpensive switches with low port counts to accommodate additional servers for increased performance, bandwidth and capacity. In essence, grid storage is a way to scale out rather than up, using relatively inexpensive storage building blocks.
【英文篇名】 Switch Router Operating System Based on a General Operating System 【下载频次】 ☆ 【作者】 潘登; 徐佩霞; 【英文作者】 PAN Deng; XU Pei xia （Department of Electronic Engineering and Information Science; University of Science and Technology of China; Hefei; 230027; China）; 【作者单位】 中国科学技术大学电子工程与信息科学系; 230027; 【文献出处】 数据采集与处理 , Journal of Data Acquisition & Processing, 编辑部邮箱 2003年 04期 期刊荣誉：中文核心期刊要目总览 ASPT来源刊 CJFD收录刊 【中文关键词】 交换式路由器; 通用操作系统; 路由器操作系统; 【英文关键词】 switch router; general operating system; router operating system; 【摘要】 提出了一种将通用操作系统及其上层路由软件移植到交换式路由器平台上的方案。此方案可以向上屏蔽交换式路由器与传统的路由器体系结构上的区别 ,从而把通用操作系统及其上层路由软件移植到交换式路由器的平台上 ;同时兼顾数据通信和管理维护方面的需求 ,为上层路由软件提供了与传统路由器相同的接口 ,从而使基于通用操作系统的路由软件可以在不损失可升级性的条件下快速移植到交换式路由器上。实际应用证实了该方案具有良好的灵活性和兼容性 【英文摘要】 A new solution to port general operating systems and their routing software to switch router is presented. The solution shields the architecture difference between traditional router and switch router to application level software, thus it may support general operating system and their routing software on switch router platform. The solution is also considered as requirements of both data communication and control functions. And same ways of the access and control of the router are provied as traditional ro... 【基金】 国家 8 63计划 ( 863 -3 1 7-0 1 -99)资助项目 【DOI】 CNKI:SUN:SJCJ.0.2003-04-017 【分类号】 TN915.05 【正文快照】 引 言路由器最重要的工作是根据 IP包头和路由、过滤规则转发 IP包。其他功能还包括路由表的维护与路由器系统的维护。实际上路由器可以看成是一种针对 IP网络路由需求而设计的专用计算机。随着因特网所承载的业务的演进 ,因特网对于路由器性能的要求也日渐提高。在交换式路 看看这一篇 文章编号: 100429037 (2003) 0420450205一种基于通用操作系统的交换式路由器操作系统实现潘 登, 徐佩霞(中国科学技术大学电子工程与信息科学系, 合肥, 230027)摘要: 提出了一种将通用操作系统及其上层路由软件移植到交换式路由器平台上的方案。此方案可以向上屏蔽交换式路由器与传统的路由器体系结构上的区别, 从而把通用操作系统及其上层路由软件移植到交换式路由器的平台上; 同时兼顾数据通信和管理维护方面的需求, 为上层路由软件提供了与传统路由器相同的接口, 从而使基于通用操作系统的路由软件可以在不损失可升级性的条件下快速移植到交换式路由器上。实际应用证实了该方案具有良好的灵活性和兼容性。关键词: 交换式路由器; 通用操作系统; 路由器操作系统中图分类号: TN 915105; TP393 文献标识码:A 基金项目: 国家863 计划(8632317201299) 资助项目 收稿日期: 2003203229; 修订日期: 2003206215Switch Router Operating System Based ona General Operating SystemPA N D eng , X U P ei2x ia(Department of Elect ronic Engineering and Info rmat ion Science,U niversity of Science and Techno logy of Ch ina, Hefei, 230027,Ch ina)Abstract: A new so lu t ion to po rt general operat ing system s and their rou t ing sof tw are tosw itch rou ter is p resen ted. The so lu t ion sh ields the arch itectu re difference betw een t radit ionalrou ter and sw itch rou ter to app licat ion level sof tw are, thu s it may suppo rt general operat ingsystem and their rou t ing sof tw are on sw itch rou ter p latfo rm. The so lu t ion is also con sidered asrequ iremen t s of bo th data commun icat ion and con t ro l funct ion s. A nd same w ays of the accessand con t ro l of the rou ter are p rovied as t radit ional rou ter, so rou t ing sof tw are of the generaloperat ing system may be po rted to sw itch rou ter p latfo rm rap idly w ith the upgradeab lef lex ib ility. P ract ical design app roves that the so lu t ion has a good compat ib ility and f lex ib ility.Key words: sw itch rou ter; general operat ing system; rou ter operat ing system引 言路由器最重要的工作是根据IP 包头和路由、过滤规则转发IP 包。其他功能还包括路由表的维护与路由器系统的维护。实际上路由器可以看成是一种针对IP 网络路由需求而设计的专用计算机。随着因特网所承载的业务的演进, 因特网对于路由器性能的要求也日渐提高。在交换式路由器中, 包转发等绝大多数处理已经转移到以端口为中心的硬件中完成, 只有路由规则的生成与维护、网络管理和系统维护等比较复杂的工作仍由软件部分完成。实用中路由器所采用的操作系统可分为三大类: (1) 以Cisco 的IO S 为代表的专用操作系统, 常见于网络骨干节点; (2) 以V xWo rk s 为代表的嵌入式系统, 常见于小型办公ö家用接入设备上; (3)采用通用操作系统的则在骨干节点和用户接入设备上都有这类设备。例如Jun iper 的路由产品就采用L inux 作为操作系统。通用操作系统上的各种路由、网管软件的开发已经有相当长时间, 其功能、性能、稳定性和升级灵活性都很优秀, 但这些软件仍第18卷第4期2003 年12 月数据采集与处理Journal of Data A cquisit ion & P rocessingVo l. 18 No. 4Dec. 2003然是针对传统路由器体系结构开发的, 无法直接应用于新的路由器体系结构。本文提出在通用操作系统的驱动栈中插入一个中间层, 这样对系统内核及和运行在其上的路由、网管等上层软件屏蔽了下层硬件的特殊性, 从而把上层软件和高速硬件平台结合起来。该方案已经应用于高速边缘路由器中, 并表现出了良好的实用性和可扩展性。1 交换式路由器与传统路由器在体系结构上的差别路由器工作在网络的第三层, 其处理工作主要涵盖七层模型中的下三层, 包括: 物理接口处理、数据链路层处理、网络层的路由查找、转发以及队列管理等[1 ]。在传统的路由器体系结构中, 硬件部分只实现物理层的处理, 其余工作需要消耗系统计算资源完成: 包括CPU 周期、内存容量和总线带宽等, 因此性能也受限于这些资源。而在交换式路由器中, 路由处理机仅处理系统维护、路由表维护等少量工作, 数据流的处理都由相对独立的硬件完成, 不再受限于系统计算资源, 因此其性能远优于传统路由器[2 ]。如图1 所示。(a) 传统路由器体系结构(b) 交换式路由器体系结构图1 路由器的逻辑结构 传统路由器和交换式路由器在体系结构方面有明显的区别: 在传统路由器中, 所有的物理接口直接挂接在总线上, 内核可以通过总线直接访问这些接口; 而在交换式路由器中, 只有控制卡是直接挂接在总线上的, 内核必须通过控制卡间接访问各个接口。这导致操作系统内核中代表网络接口的驱动对象的区别: 在传统路由器中, 内核存在若干网络设备驱动对象实例, 每个实例通过总线直接维护一个端口, 为内核及其上面的上层软件提供基本操作支持。而在交换式路由器中, 普通的网络设备驱动对象无法直接维护端口, 也无法支持系统内核和上层软件操作。因此, 交换式路由器体系结构的特殊性使得通用操作系统和上层软件无法直接应用。针对这个问题有两种解决办法: (1) 大量修改内核和各种相关软件的源代码以适应新的体系结构。这种做法存在开发工作量大、周期长、局限性强的缺点, 丧失了使用通用操作系统的灵活性; (2) 在驱动栈中增加一个中间层, 支持普通网络驱动对象所能支持的一切操作, 这样系统内核和上层软件基本上不必修改就可以运行在交换式路由器上。这就是本文所提出的中间层方案。这种方案克服了第一种方法的复杂性, 在保持灵活性的基础上, 可以快速地把通用操作系统及上层软件移植到交换式路由器的硬件平台上。2 中间层设计中间层功能包括数据通信和控制两个方面。从数据通信方面考虑, 每个端口的功能都等效于传统路由器中的一个网络接口, 所以每个物理端口在内核中都应有对应的网络驱动实例。这样才能支持各种上层软件运行, 满足数据通信功能的需要。从控制功能方面考虑, 对上要把每一种可能的逻辑操作映射成硬件操作; 对下要能够和多个设备通信。上层应用包括系统维护、路由软件、网管软件; 下层设备包括处理引擎和端口。控制功能的具体实现和硬件平台有关。考虑到多种应用可能同时操作一个硬件设备, 一种应用也可能同时操作多个设备, 在实现时必须考虑到对于多并发操作的支持。基于上述考虑, 中间层由控制卡驱动模块和若干网络驱动实例组成。在图2 (a, b) 中分别给出了传统路由器的结构与驱动方式以及本文所提出的中间层所处的位置与驱动方式。第4 期潘 登, 等: 一种基于通用操作系统的交换式路由器操作系统实现451图2 中间层的位置与驱动方式 控制卡驱动模块作为中间层的核心, 维护控制卡上所有的端口、内存映射、中断和循环缓冲队列资源。它实现了数据通道和控制通道。对下直接驱动控制卡、与各个端口、处理引擎通信; 对上, 一方面通过内核调用陷阱方式提供控制通道接口; 另一方面向虚拟网络驱动实例提供数据通道接口。虚拟网络驱动实例在操作系统内核为各个物理端口实现网络驱动实例。它们工作在控制卡驱动模块的基础上, 并不直接控制硬件, 故称为虚拟网络驱动实例。虚拟网络驱动实例封装控制卡驱动模块提供的数据传输功能, 并为内核和上层软件提供与普通网络驱动实例相同的调用接口。下面分别给出数据通道和控制通道的实现方案。211 数据通道的功能与实现虚拟网络驱动实例和物理端口是一一对应的。内核数据收发的功能包括3 个方面:(1) 发往某虚拟网络驱动实例的数据包应该由其对应端口输出;(2) 这个端口所收到的包也通过该虚拟网络驱动实例向系统内核提交;(3) 中间层也可以对虚拟网络驱动实例进行流控操作, 以避免因拥塞导致数据丢失。注意到图2 (b) 中的交换结构以定长信元交换数据, 其格式如图3 所示, 其中信元头占4 字节, 包括处理引擎号和端口号域。对于收ö发信元, 处理引擎号和端口号分别为该信元的源端口的和目的端口的对应值。根据图2 (b) 所示的系统结构可知: 由处理引擎号和端口号可以确定端口的物理位置。控制卡驱动模块在其内部的驱动信息数组中维护虚拟网络驱动实例和端口之间的对应关系。图3 数据信元结构发送数据时, 虚拟网络驱动实例从内核网络部分获取待发送的数据, 偕同指向该实例自己的指针一起提交给控制卡驱动模块。一方面, 控制卡驱动模块通过这个指针可以对虚拟网络驱动实例进行流控设置; 另一方面, 控制卡驱动模块根据虚拟网络驱动实例指针查驱动信息表得到目标端口物理位置信息, 包括处理引擎号和端口号。端口物理位置信息将被填充到所有用来承载待发送数据包的信元头中。控制卡驱动模块通过控制卡把信元送到交换结构, 而交换结构和处理引擎分别根据处理引擎号和端口号将信元转发到到目标端口。最后端口从接收到的信元中恢复出原始数据发出。接收数据时, 端口也会将数据拆分到若干信元中逐级上传。考虑到交换结构的循环优先机制, 一个数据包上传的过程可能被来自其他端口的数据抢断。所以控制卡驱动模块对于接收到的信元按源端口位置信息(包括处理引擎号和端口号) 保存到不同的缓冲区中。当接收到该数据包相关的全部信元, 控制驱动模块即可重组该数据, 并根据源端口位置信息查驱动信息表以得到指向该端口对应虚拟网络驱动实例的指针, 进而激活该虚拟网络驱动实例接收数据。虚拟网络驱动实例从控制卡驱动模块中获取数据后, 按照网络驱动的常规方式调用net if- rx 接口向内核提交数据。数据收发实现结构如图4 所示。值得注意的是, 在交换式路由器中, 处理引擎通过交换结构交换的是IP 包; 而通用操作系统中452 数据采集与处理第18 卷图4 数据收发实现结构网络驱动通常处理链路层的帧。即控制卡驱动模块数据通道对上对下的数据格式是不同的。因此, 在发送数据时控制卡驱动模块需要从得到的链路帧中提取IP 包再转发到端口; 而接收数据时则对来自端口的IP 包进行链路帧封装再向上提交。以以太网为例, 需要恢复的包括源和目标站的物理地址、载荷类型和帧校验[3 ]。对于承载IP 包的以太帧, 显然其目标站物理地址和载荷类型[4 ]都是已知的。实现时采用的操作系统是L inux, 通过在虚拟网络驱动源代码中进行设置可以使内核不进行帧校验[5 ]。所以只有源站物理地址未知。如果要求硬件给出真实的源站物理地址, 则增加了硬件的复杂度; 而若在控制卡驱动模块中伪造源物理地址, 则可能导致内核的ARP 管理混乱。为简化硬件设计, 实现时采用了在控制卡驱动模块中伪造源物理地址的办法, 同时修改虚拟网络驱动源代码, 重载帧头处理函数[6 ]。这样内核ARP 表就不受伪造地址的影响, 其获取和刷新通过查询端口ARP 记录实现。212 控制通道的功能与实现控制功能的通信也是基于信元的, 其操作包括维护管理和表同步两类。维护管理主要是进行各种查询, 通常通过若干次双向通信完成。每次通信有效载荷都只有几个字节, 由一个信元即可承载。而表同步则是将上层软件维护的表复制到相关硬件中, 包括ARP 表、路由和分类表等。表同步操作涉及大量数据传输, 需要由多个信元承载。控制功能都是针对设备进行的, 所以在控制ö反馈信元中也必须包括目标设备的物理位置信息。在实际运行期间, 所有的上层应用和设备之间的控制通信复用控制通道, 其特点为:(1) 不同的应用可能同时访问同一设备;(2) 一个应用也可能同时访问多个设备;(3) 同一应用对于同一个设备的操作一般都是顺序的。为支持这种复用操作, 所有承载控制信息和反馈信息的头部除包括目标硬件的物理位置和操作指令外, 还包括命令类型、应用类型信息。控制ö反馈用信元结构如图5 所示。图5 控制ö反馈信元结构图5 中: 处理引擎号和端口号, 确定设备的物理位置; 收ö发信元分别为该信元的源端口的和目的端口的对应值; 命令码在设备和应用之间定义。每种可能的操作分配一个代码; 应用码在控制卡驱动模块和上层应用之间预定义。每种可能的应用分配一个代码。这些应用包含网管、路由维护、硬件维护和ARP 信息获取等。上层应用通过内核调用陷井( IOCTL ) 发起控制通道操作, 同时给出目标设备物理位置、命令类型代码和应用类型代码。控制卡驱动模块把这些信息填充到控制信元中再将其发往设备。设备把这些代码直接复制到反馈信元中, 再在后面追加上反馈信息。控制卡驱动模块为每一种应用分配一个循环缓冲区, 把收到的反馈根据应用类型排入相应队列中。上层应用从其所对应的循环缓冲区中读取反馈信元, 然后根据信元中的物理位置信息、命令码就可以确定该反馈对应的原始命令, 从而对反馈数据进行适当处理。这样就实现了各种控制功能对控制通道的复用。如图6 所示。第4 期潘 登, 等: 一种基于通用操作系统的交换式路由器操作系统实现453图6 控制通信实现结构3 结 论鉴于传统路由器体系结构和交换式路由器体系结构的区别, 通用操作系统及在其上开发的路由软件无法直接应用于交换式路由器。本文提出的中间层方案可以有效地解决这个问题。该方案全面考虑了数据通信和管理维护方面的需求, 为上层提供了与原有模型基本相同的接口, 并使得路由软件在不损失其灵活性和可升级性的条件下直接应用于交换式路由器中。虽然该方案只是在特定的平台和特定的操作系统上得到了实现, 但是不难看出, 这种思路对操作系统并没有特殊的依赖性, 完全可以移植到其他通用操作系统上。本文提出的方案已经在国家863 项目实用化综合接入系统的高速边缘路由器的研制中取得了良好的实际效果。本文为国产高性能路由器的软件开发提出了一种高效快捷的解决方案, 该方案具有良好的应用前景。参考文献:[1 ] Kuro se J F, Ro ss KW. Computer netwo rk ing: a top2dow n app roach featuring the internet [M ]. A ddisonW esley Longman′s P ress, 2001. 332～ 341.[ 2 ] 梁阿磊, 等. 路由器体系结构及其发展[J ]. 小型微型计算机系统, 2001, 8: 943～ 945.[3 ] M edia access cont ro l frame st ructure [S ]. IEEE Std80213, 1998. 36～ 40.[ 4 ] Charles Ho rnig. RFC 894: a standard fo r the t rans2m ission of IP datagram s over Ethernet netwo rk s[S ].198411～ 2.[5 ] Bovet D P. U nderstanding L inux kernel[M ]. O reil2ley P ress, 2002. 683～ 685[ 6 ] Rubini A. L inux device drivers. 2nd edit ion [M ].O r2eilley P ress, 2001. 455～ 458作者简介: 潘 登(19772) , 男, 博士研究生, 研究方向: 网络体系结构、网络安全, E2mail: pandeng@mail. ustc. edu. cn;徐佩霞(19412) , 女, 教授, 博士生导师, 研究方向: 音频视频编码、非线性处理、下一代网络。454 数据采集与处理第18 卷
use puter regularly and just a short time everyday. Spending long time or without control before puter is not good to your heathy.2. use puter when it is in need. Teachers may ask to find some useful information or some problems is puzzed you by your homeworks, at this moment puter will be a good helper.3. avoid more games,musics, movies and chattings. This will squeeze study time out and still will make some problems beeem you and family. 1。利用计算机经常只是短时间的日常。长时间在电脑前或不控制不好你的健康。 2。使用计算机时，它需要的是。老师可能会问到的一些问题，找到一些有用的资讯或是puzzed你的家庭作业，这时电脑会是一个好帮手。 3。避免更多的游戏，音乐，电影和chattings。这将把研究的时间，还将使你和家人之间的一些问题。望采纳
Most parents and teachers think it is a bad thing to play puter games.They think it is a waste of time and money.Playing too many puter games is also bad for children's eyes and health. However,puter games can also bring some benefits.They can help people in many ways if people spend proper time on it.Some puter games can improve people's ability of thinking.They can make people think in different ways.Playing puter games can also help people be familiar with the keyboard.If people are familiar with the keyboard,they can type fast. More and more people begin to disign educational CD-ROM.They want go any people to gain some knowledge while they are playing puter games. 大多数家长和老师认为玩电脑游戏是件坏事，他们觉得这是时间和金钱的浪费。过度地玩电脑游戏也会损害孩子的眼睛及健康. 然而,电脑游戏也可以带来一些益处.如果玩游戏的时间适当，人们还是能够以很多方式从中受益。一些电脑游戏可以提高人们的思考能力，让人们用不同的方法去思考。玩电脑游戏也会帮助人们熟悉键盘。熟悉键盘，打字就会很快. 越来越多的人开始设计制作教育光碟.他们想让人们在玩电脑游戏的同时学到一些知识.
The puter is a very useful machine. It is the most important invention in many years.People use it widely today in many ways. Most puters have memories.People can store information in them and take it out at any time.Computers are getting *** aller and *** aller, and working faster and faster. Computer can do many kinds of work.Now in many large factories there are very few people. Computers do most of the work.They really help a lot.
Good environment can make people feel happy and fit . To improve the environment means to improve our life. We should plant more trees and flowers around us . We shouldn’t cut them down . We should s factories from pouring waste water into the river and waste gas into the air. Whenever we see litter on the ground , we should pick it up and throw it into du *** ins. Never spit in public. Don’t draw on public walls. It’s our duty to protect the environment.
What do you think of puter? Computer is very useful for us. The Inter is a great facility for collecting information. The Inter makes it easy to build social connections. we can have a lot of friends all over the world and reach much knowledge by Inter. Millions of people municate today through E-mail. But the disadvantages of puter also have a lot. The neork information may be falsehood, so mach as leading to a wrong decision-making. May online socialization weaken our ability to deal with relationships in the real world? The weak-willed persons maybe indulge neork-game and amusement in Inter thereby disrepair own career. The loveliness of Inter is infinitude and colorful, but strengthen to manage it. We make good use of it only while we have an appropriate approach to Inter . 2.What do you think of puter? The inter play a very important role in our daylife.Everyday thousands people surf the .With the help of the you can get many useful imformations,you can make friends with different people who are known or unkown,you can ask the help or question the answer. Every coin has o sides,there are so much rubbish on the ,which are some medium messageses about crime or sex.Morever the cost is large,which also make peopl waste time on it. It's abilities should used by people.We should correctly take the advantage of the ,make our life more beautiful.
With the development of the puter technology and the inter,we have got a new media to know the outside world.And our life is greatly changed with it.On the inter,you can get both the domestic news and the international news as well.For our daily munication, you can send E-mails to your friends and the other people.Of course,you can study whatever you like on the inter,such as, English and other subjects.Meanwhile,you can appreciate music,sports and enjoy the video games.Recently,more and more people,especially young people,are interested in shopping online.Anyway,inter is changing our style of life and the way of thinking as well. It is no doubtthat puter and its inter play very important part in our life,study and work.On the puter,we can look for some new and fresh information so that we can study more knowledge.And more and more people realize that we are in the non-paper times. That's to say we can do lots of things without paper like before.But meanwhile,some people,especially some young people are too addicted to the video games on the puter inter.It is a waste of time and energy.So,the question whether a puter is good or bad depends on how we use it.If we use it in a proper way,it will be very helpful to our life and study.
Taking care of yourself may seem like a full-time job. Neglecting that "job" though can harm your confidence, relationships and enjoyment of life. It is important to take care of yourself as it ensures a happier and healthier life, as well as helping you to be more a part of the munity you're in.Have a good attitude. Taking care of yourself means on the inside too. If you always feel negative, consider getting help to change this approach, whether it be via therapy, reading self-help books or spending time around more upbeat people. I should s worrying about myself and do something! 根据自身情况修改内容。希望能够帮到你！【ABC.Snap】
Abraham Lincoln Abraham Lincoln was born in a log cabin in Kentucky on February 12, 1809. When he was a *** all boy, his family moved to the frontier of Indiana. Here, his mother tanght him to read and write. He loves learning and studies very hard. Lincohn si a great man.He had to earn a living at an early age, but in his leisure time he studied law. He soon became one of the best-known lawyers. Later, after a lot of hard work.. He became the President of the United States. He made a great contributions to the United States. He is example for our study. I like him. 希望对您有帮助！谢谢！
Spring Festival is the most important festival in China. 春节是中国最重要的节日。 It’s to celebrate the lunar calendar's new year.In the evening before the Spring Festival,families get together and have a big meal. 春节是为了庆祝农历新年的来临。除夕夜,一家人聚在一起吃一顿丰盛的年夜饭。 In many places people like to set off firecrackers,Dumplings are the most traditional food. 在很多地方，人们都会放鞭炮，饺子是最传统的食物。 Children like the festival very much,because they can have delicious food and wear new clothes. 孩子们非常喜欢这个节日,因为他们可以有好吃的食物同时可以穿新衣服。 They can also get some money from their parents. 他们也能得到父母给的压岁钱。 This money is given to children for good luck. 压岁钱给孩子们,以求好运。 People put New Year scrolls on the wall for good fortune. 人们把春联贴到墙上，以求好运。 The Spring Festival lasts about 15 days long.People visit relatives and friends with the words “Have all your wishes ”.People enjoy the Spring Festival, during this time they can have a good rest . 春节将持续大约15天，人们在拜访亲朋好友前常用这句话:“祝愿”。人们喜欢春节,因为在这段时间里他们可以好好休息一下了。
I like the puter extremely, I play some neork game frequently, I like on the puter listening to the song, consults the material on the puter to be very convenient.I have very many friends in the neork, we may municate.I started from the childhood to contact the puter, therefore I understood very much to the puter.I like the puter! 我非常喜欢电脑，我经常玩一些网路游戏，我喜欢在电脑上听歌，在电脑上查阅资料很方便。我在网路上有很多朋友，我们可以沟通。我从小时候就开始接触电脑，所以我对电脑很了解。我喜欢电脑！ 你看可以不