【计算机专业文献翻译】Line 控件

计算机各种错误信息翻译电脑各种错误信息的中文意思(绝对有用!)一、BIOS中的提示信息提示信息说明Drive A error 驱动器A错误System halt 系统挂起Keyboard controller error 键盘控制器错误Keyboard error or no keyboard present 键盘错误或者键盘不存在BIOS ROM checksum error BIOS ROM 校验错误Single hardisk cable fail 当硬盘使用Cable选项时硬盘安装位置不正确FDD Controller Failure BIOS 软盘控制器错误HDD Controller Failure BIOS 硬盘控制器错误Driver Error 驱动器错误Cache Memory Bad, Do not Enable Cache 高速缓存Cache损坏，不能使用Error: Unable to control A20 line 错误提示：不能使用A20地址控制线Memory write/Read failure 内存读写失败Memory allocation error 内存定位错误CMOS Battery state Low CMOS没电了Keyboard interface error 键盘接口错误Hard disk drive failure 加载硬盘失败Hard disk not present 硬盘不存在Floppy disk(s) fail (40) 软盘驱动器加载失败，一般是数据线插反，电源线没有插接，CMOS 内部软驱设置错误CMOS checksum error-efaults loaded. CMOS校验错误，装入缺省(默认)设置二、BIOS刷新失败后，Bootblock启动时出现的提示信息提示信息说明Detecting floppy drive A media... 检测软驱A的格式Drive media is : 1.44Mb1.2Mb 720Kb 360K 驱动器格式是1.44Mb、12Mb、720kb、360kb的一种DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER 磁盘引导失败，插入系统盘后按任意键继续三、MBR主引导区提示信息提示信息说明Invalid partition table 无效的分区表Error loading operating sy stem 不能装入引导系统Missing operating system 系统引导文件丢失说明：如果在计算机启动过程中，在硬件配置清单下方(也就时在平时正常启动时出现Starting Windows 98…的地方)出现不可识别字符，此时可判断硬盘分区表损坏。

本科毕业论文外文翻译外文译文题目:不确定条件下生产线平衡：鲁棒优化模型和最优解解法学院：机械自动化专业：工业工程学号: 201003166045学生姓名: 宋倩指导教师：潘莉日期: 二○一四年五月Assembly line balancing under uncertainty: Robust optimization modelsand exact solution methodÖncü Hazır , Alexandre DolguiComputers ＆Industrial Engineering，2013,65：261–267不确定条件下生产线平衡：鲁棒优化模型和最优解解法安库·汉泽，亚历山大·多桂计算机与工业工程，2013，65：261–267摘要这项研究涉及在不确定条件下的生产线平衡，并提出两个鲁棒优化模型。

假设了不确定性区间运行的时间。

该方法提出了生成线设计方法,使其免受混乱的破坏。

基于分解的算法开发出来并与增强策略结合起来解决大规模优化实例.该算法的效率已被测试,实验结果也已经发表。

本文的理论贡献在于文中提出的模型和基于分解的精确算法的开发.另外，基于我们的算法设计出的基于不确定性整合的生产线的产出率会更高，因此也更具有实际意义。

此外,这是一个在装配线平衡问题上的开创性工作,并应该作为一个决策支持系统的基础。

关键字：装配线平衡；不确定性; 鲁棒优化；组合优化；精确算法1.简介装配线就是包括一系列在车间中进行连续操作的生产系统。

零部件依次向下移动直到完工。

它们通常被使用在高效地生产大量地标准件的工业行业之中。

在这方面，建模和解决生产线平衡问题也鉴于工业对于效率的追求变得日益重要。

生产线平衡处理的是分配作业到工作站来优化一些预定义的目标函数。

那些定义操作顺序的优先关系都是要被考虑的,同时也要对能力或基于成本的目标函数进行优化。

就生产（绍尔，1999）产品型号的数量来说，装配线可分为三类：单一模型（SALBP）,混合模型(MALBP）和多模式（MMALBP）。

单位代码10学号分类号TP393密级文献翻译计算机网络安全和防范院（系）名称专业名称学生姓名指导教师QQ 997237619年2月28日英文译文计算机网络安全和防范在信息时代，信息可以帮助团体或个人，使他们从中受益，同样的信息也可以被用来威胁到他们，造成的损失。

因此，网络安全，包括组成的网络硬件，软件和网络传输的信息安全，使他们不因意外或恶意破坏的攻击，网络安全不仅是技术方面，而且还管理问题，既相互补充另一方面，是不可或缺的。

国际标准化组织的“计算机安全”的定义是：“要建立一个数据处理系统，并通过技术和管理的安全保护，保护计算机硬件，软件，数据不因偶然和恶意破坏的原因，更改和泄漏。

“上述定义的计算机安全包括人身安全和逻辑安全性的内容的内容的逻辑，安全可被理解为我们常说，信息安全，是指信息的保密性，完整性和可用性的保护，网络保障信息安全的含义是延长，这是一个网络安全的信息网络的保密性，完整性和可用性的保护。

计算机网络安全的具体含义，用户的变化，不同的用户对网络安全的认识和要求会有所不同。

从普通用户的角度来看，只能希望，个人隐私或机密信息的传输网络上的受到保护，防止窃听，篡改和伪造;和网络提供商除了关心这些网络信息安全，我们还必须考虑如何处理突发自然灾害，如军事打击破坏网络硬件，以及网络中的不寻常如何还原网络通讯，并保持连续性的网络通信。

从本质上讲，网络安全，包括组成的网络硬件，软件和网络传输的信息安全，使他们不因意外或恶意攻击的破坏双方的技术方面的网络安全问题，有管理的问题，双方互为补充，是不可或缺的。

人为的网络入侵和攻击使网络安全面临新的挑战。

计算机网络安全是网络硬件，软件和数据系统免遭意外或恶意破坏的原因，改建，披露，该系统连续，可靠，正常运行的网络服务不中断。

计算机和网络技术的复杂性和多样性，使计算机和网络安全已经成为一个需要继续更新和改善该地区。

目前，黑客攻击方法已超过计算机病毒的类型，而且许多攻击是致命的。

中英文资料外文翻译AC Voltage and Current Sensorless Control ofThree -Phase PWM Rectifiers1 THREE -PHASE PWM RECTIFIERSA System ModelingFig . 1 shows the power circuit of the three -phase PWM rectifier . The voltage equations are given by000000a a a b b b c c c R pL R pL R pL e i v e i v e i v ⎡⎤⎡⎤⎡⎤+⎛⎫⎢⎥⎢⎥⎢⎥ ⎪=++⎢⎥⎢⎥⎢⎥ ⎪⎢⎥⎢⎥⎢⎥ ⎪+⎝⎭⎢⎥⎢⎥⎢⎥⎣⎦⎣⎦⎣⎦ (1)Fig. 1. Three-phase PWM rectifier without ac-side sensors.where , and are the source voltage, the line current, and the rectifier input voltage, respectively and are the input resistance and the input inductance, respectively . When the peak line voltage , angular frequency , and initial phase angle are given, assuming a balanced three -phase system, the source phase voltage is expressed ascos 2cos()32cos()3a b c E e e e θθπθπ⎡⎤⎢⎥⎡⎤⎢⎥⎢⎥⎢⎥=-⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎣⎦⎢⎥+⎣⎦ (2) Where0t θωθ=+ (3)A transformation matrix based on the estimated phase angle ,which transforms three -phase variables into a synchronous d –q reference frame, is23222cos cos()cos()323sin sin()sin()M M M M M M C θθπθπθθπθπ⎛⎫-+ ⎪ ⎪= ⎪++ ⎪⎝⎭ (4)Transforming (1) into the – reference frame using (4)qc qc qc M M dc dc dc e i v R pL L L R pL e i v ωω⎡⎤⎡⎤⎡⎤+-⎛⎫=+⎢⎥⎢⎥⎢⎥ ⎪+⎝⎭⎣⎦⎣⎦⎣⎦ (5)where p is a differential operator and .M M ωθ=Expressing (5) in a vector notationM e Ri LJi pLi v ω=+++ (6) where,qc dc e e e ⎡⎤=⎢⎥⎣⎦,qc dc i i i ⎡⎤=⎢⎥⎣⎦,qc dc v v v ⎡⎤=⎢⎥⎣⎦,0110J -⎛⎫= ⎪⎝⎭ (7) Taking a transformation of (2) by using (4)cos sin E e E θθ∆⎡⎤=⎢⎥∆⎣⎦ (8) WhereM θθθ∆=- (9)Expressing (6) and (8) in a discrete domain, by approximating the derivative term in (6) by a forward difference [9], respectively,[](1)(1)(1)()(1)(1)M e k Ri k LJi k L i k i k v k T ω-=-+-+--+- (10)c o s (1)(1)s i n (1)E k e k E k θθ∆-⎡⎤-=⎢⎥-∆-⎣⎦(11)Where T is the sampling period .Fig. 2. Overall control block diagram.B System ControlThe PI controllers are used to regulate the dc output voltage and the ac input current . For decoupling current control, the cross -coupling terms are compensated in a feed forward -typeand the source voltage is also compensated as a disturbance . For transient responses without overshoot, the anti -windup technique is employed [10]. The overall control block diagram eliminating the source voltage and line current sensors is shown in Fig . 2. The estimation algorithm of source voltages and line currents is described in the following sections .2 PREDICTIVE CURRENT ESTIMATIONThe currents of ()a I k and ()c I k can not be calculated instantly since the calculation time of the DSP is required . To eliminate the delay effect, a state observer can be used . In addition, the state observer provides the filtering effects for the estimated variable .Expressing (5) in a state -space form,x Ax Bu =+ (12) y Cx = (13) where,R L A R L ωω⎛⎫-- ⎪= ⎪ ⎪- ⎪⎝⎭,1010L B L ⎛⎫ ⎪= ⎪ ⎪ ⎪⎝⎭,1001C ⎛⎫= ⎪⎝⎭qc dc i x i ⎡⎤=⎢⎥⎣⎦,qc qc dc dc e v u e v -⎡⎤=⎢⎥-⎣⎦ And y is the output .Transforming (12) and (13) into a discrete domain, respectively,(1)()()X k FX k GU k +=+ (14)()()Y k HX k = (15)where,1111R T T L F R T T L ωω⎛⎫-- ⎪= ⎪ ⎪+- ⎪⎝⎭,00T L G T L ⎛⎫ ⎪= ⎪ ⎪ ⎪⎝⎭Then, the observer equation adding an error correction term to is given by(1)()()(()())X k F X k GU k K Y k Yk +=++- (16) Where K is the observer gain matrix and “＾ ” means the estimated quantity, and (1)X k + is the state variable estimated ahead one sampling period . Subtracting (15) from (16), the error dynamic equation of the observer is expressed as(1)[]()rr rr e k F KC e k +=- (17) where ()()()rr e k X k X k =- . Here, it is assumed that the model parameters match well with the real ones . Fig . 3 shows the block diagram of the closed -loop state observer .The state variable error depends only on the initial error and is independent of the input . For (17) to converge to the zero state, the roots of the characteristic equation of (17) should be located within the unit circle .Fig. 3. Closed-loop state observer.Fig. 4. Short pulse region.4EXPERIMENTS AND DISCUSSIONSA. System Hardware ConfigurationFig. 5shows the system hardware configuration. The source voltage is a three-phase,110[V].The input resistance and inductance are0.06Ωand3.3 mH,respectively. The dc link capacitance is2350μF and the switching frequency of the PWM rectifier is3.5kHz.Fig. 5. System hardware configuration.Fig. 6. Dc link currents and corresponding phase currents (in sector V ).The TMS320C31DSP chip operating at33.3MHz is used as a main processor and two12-b A/D converters are used. One of them is dedicated for detecting the dc link current and the other is used for measuring the dc outputvoltage and the source voltages and currents,where ac side quantities are just measured for performance comparison.One of two internal timers in the DSP is employed to decide the PWM control period and the other is used to determine the dc link current interrupt. Considering the rectifier blanking time of3.5s,A/D conversion time of2.6s, and the other signal delay time,the minimum pulse width is set to10s.A.Experimental ResultsFig. 6shows measured dc link currents and phase currents. In case of sector V of the space vector diagram,the dc link current corresponds to for the switching state of and for that of . Fig. 7(a)shows the raw dc link current before filtering. It has a lot of ringing components due to the resonance of the leakage inductance and the snubber capacitor. When the dc current is sampled at the end point of the active voltage vectors as shown in the figure,the measuring error can be reduced.Fig. 7. Sampling of dc link currents.Fig. 8. Estimated source voltage and current at starting.To reduce this error further,the low pass filter should be employed,of which result is shown in Fig. 7(b). The cut-off frequency of the Butterworth’s second-order filter is112kHz and its delay time is about2sec. Since the ringing frequency is258kHz and the switching frequency is3.5[kHz],the filtered signal without significant delay is acquired.Fig. 8shows the estimated source voltage and current at starting. With the proposed initial estimation strategy,the starting operation is well performed. Fig. 9shows the phaseangle,magnitude,and waveform of the estimated source voltage,which coincide well with measured ones.Fig. 10shows the source voltage and current waveform at unity power factor. Figs. With the estimated quantities for the feedback control,the control performance is satisfactory. The dc voltage variation for load changes will be remarkably decreased if a feedforward control for theload current is added, which is possible without additional cur-rent sensor when the PWM rectifier is combined with the PWM inverter for ac motor drives.(a) phase angle (b)magnitude (c) waveform.Fig. 10. Source voltage and current waveforms.(a)estimated (b) measured.4 CONCLUSIONSThis paper proposed a novel control scheme of the PWM rectifiers without employing any ac input voltage and current sensors and with using dc voltage and current sensors only. Reducing the number of the sensors used decreases the system cost as well as improves the system reliability. The phase angle and the magnitude of the source voltage have been estimated bycontrolling the deviation between the rectifier current and its model current tobe zero. For line current reconstruction,switching states and measured dc link currents were used. To eliminate the effect of the calculation time delay of the microprocessor,the predictive state observer was used. It was shown that the estimation algorithm is robust to the parameter variation. The whole algorithm has been implemented for a proto-type1.5[kV A]PWM rectifier system controlled by TMS320C31DSP. The experimental results have verified that the proposed ac sensor elimination method is feasible.无交流电动势、电流传感器的三相PWM整流器控制1三相PWM整流器A 系统模型图一所示为三相PWM 整流器的主电路，电压等式给出如下：000000a a a b b b c c c R pL R pL R pL e i v e i v e i v ⎡⎤⎡⎤⎡⎤+⎛⎫⎢⎥⎢⎥⎢⎥ ⎪=++⎢⎥⎢⎥⎢⎥ ⎪⎢⎥⎢⎥⎢⎥ ⎪+⎝⎭⎢⎥⎢⎥⎢⎥⎣⎦⎣⎦⎣⎦ (1)图1 无交流传感器三相PWM 整流器其中e ，i 和v 分别是源电压，线电流和整流器的输入电压，R 和L 分别是输入电阻和输入电感。

principal number 主数master data 主数据master data sheet 主数据表primary data set group 主数据集组master data control console 主数据控制台master data base 主数据库primary data base manager 主数据库管理程序main data area 主数据区master data file 主数据文件host data language 主数据语言chief series 主数列kingbolt 主栓main canal 主水道basic tax 主税principal tetrahedron 主四面体main servomotor 主伺服电动机main suit 主诉master speed tape 主速度带track rope 主索master index 主索引prime index 主索引machine tower 主塔key station 主控台main station 主台master 主台master station 主台master mode 主状态master mode program 主态程序master mode entry instruction 主态入口指令master mode bit 主态位main spring 主弹簧principal character 主特征principal character 主特征标subject 主题topic 主题subject indexing 主题标引arrangement of subjects 主题表thesaurus 主题词表thesaurus construction 主题词表结构thesaurus display 主题词表显示thematic 主题的master search file 主题检索文档thematic apperception test 主题理解测验thematic catalogue 主题目录subject data base 主题数据库subject-matter index 主题索引thematic apperception test 主题统觉测验agent 自主体host 主体main body 主体mainstream corporation tax 主体公司税base metal 主体金属body group 主体栏body group presentation rule table 主体栏表示规则表body color 主体色primary body 主天体main pressure regulator valve 主调压阀primary channel 主通道major path satellite earth station 主通道卫星地面站main channel 主通路main path 主通路major path 主通路main traffic station 主通信站main communication center 主通信中心master synchronization pulse 主同步脉冲master synchronizer 主同步器main lens 主透镜main cam 主凸轮master gyroscope 主陀螺仪primary network 主网络main network address 主网络地址host network administration facilities 主网络管理设备host network control 主网络控制primary network flow control 主网络信息流控制primary network support 主网络支援principal derivative 主微商mainmast 主桅杆main course 主桅主帆dominant dimension 主维数principal maintenance period 主维修时间host test 主文本host file 主文件main file 主文件master file 主文件owner file 主文件master file tape 主文件带master file update program 主文件更新程序host file close 主文件关闭central file on-line 主文件联机master file directory 主文件目录master file directory block 主文件目录块master file inventory 主文件清单host transceiver 主文件收发程序master file index 主文件索引host file system 主文件系统master file updating program 主文件修改程序host file enquire 主文件询问master file job processing 主文件作业处理bound vortex 主涡main couple 主屋架inner marker signal 主无线电信标信号master set 主系principal series 主系列host system 主系统main system 主系统primary system operator 主系统操作员master system tape 主系统带master system distribution tape format 主系统分配带格式host attachment 主系统连接装置primary system input source 主系统输入源程序host system mailbox 主系统信箱区host system mailbox switch setting 主系统信箱区开关设置host preparation facility 主系统准备功能light cell 集合小管主细胞principal cell 集合小管主细胞chief cell 主细胞primary index 主下标principal fibers 主纤维main display console 主显示台primary display sequence 主显示序列main line 主线main track 主线principal line 主线main line program 主线程序main line program counter 主线程序计数器main line code 主线代码main line code program counter 主线代码程序计数器main section 主线段principal series 主线系main line channel 主线信道master busy 主线占线dominant vector 主向量principal vector 主向量principal term 主项subject 主项main phase 主相kingpin 主销main pin 主销axle-pin rake 主销后倾kingpin castor angle 主销后倾角castor 主销后倾距caster action 主销后倾作用knuckle 主销连接kingpin offset 主销偏移距caster 主销倾角major gene resistance 主效基因抗病性main effect 主效应primal coordination 主协调main diagonal 主斜杆leading beacon 主信标main channel 主信道main signal 主信号master signal 主信号main signalling equipment 主信号设备host information processor 主信息处理机master letter of credit 主信用证prime credit 主信用证primary 主星primary component 主星primary star 主星primary body 主星体- 与卫星有关的major star 主星形main sequence 主星序principal penalty 主刑principal planet 主行星major 主修的- 大学学科major 主修科目- 大学学科中的major 主修学生- 大学专业的main sequence 主序principal order 主序post-main sequence star 主序后星chief series 主序列principal order module 主序模块pre-main sequence 主序前pre-main sequence star 主序前星principal series 主序系main sequence star 主序星main rotor 主旋翼primary cleaning 主选master gate control block 主选通控制块main gating pulse 主选通脉冲alveolus 主穴main loop 主循环major cycle 主循环major loop 主循环air-line main 主压气管道cardinal tooth 主牙host 主岩host rock 主岩main grinder table 主研磨台master sample 主样本master policy 主要保险单leading schedule 主要表格primary weapon 主要兵器main supply depot 主要补给仓库major component 主要部分essential element 主要部件major component 主要部件vitals 主要部件main department 主要部门main material 主要材料primary materials 主要材料main material cost 主要材料成本master stores record 主要材料帐master financial budget 主要财务预算main product 主要产品major product 主要产品principal product 主要产品main product order 主要产品定单leading firm 主要厂商prime cost 主要成本major constituent 主要成分basis material 主要成分材料basis metal 主要成分金属main contractor 主要承包商master certificate 主要单证master document 主要单证prime navaid facility 主要导航设施cardinal 主要的grand 主要的major 主要的primal 主要的main area 主要地区main order 主要定单main director 主要董事dominant motive 主要动机main angle 主要对角平巷principal fact related to crime 主要犯罪事实capital expenditure 主要费用cardinal winds 主要风向primary liabilities 主要负债stem 主要干线key post 主要岗位major project 主要工程key industry 主要工业major industry 主要工业main industrial sector 主要工业部门major industrial products 主要工业产品ground work 主要工作main company 主要公司majorcompany 主要公司key vendor 主要供货商main stockholder 主要股东leading share 主要股份leading stock 主要股份major failure 主要故障main 主要管道key management system 主要管理系统key currencies for international settlements 主要国际结算货币basal water 主要含水层main workings plan 主要巷道平面图senior partner 主要合伙人key link 主要环节principal volcano 主要火山key currency 主要货币main currency 主要货币major currency 主要货币principal currency 主要货币main organ 主要机构major organ 主要机构major gene 主要基因master plan 主要计划essential record 主要记录major technique 主要技术main precipitation core 主要降水中心major nodal earth terminal 主要结点地面终端机primary solution 主要解main manager 主要经理primary employment 主要就业major control 主要控制major control change 主要控制改变master inventory file 主要库存档案essential labour 主要劳动major part 主要零件main buyer 主要买主principal trade partner 主要贸易伙伴main title 主要名称principal proposition 主要命题principal mode 主要模式dominant mode 主要模式main crop 主要农作物main enterprise 主要企业major enterprise 主要企业major bulk 主要散装货dominant firm 主要商号staple 主要商品staple commodities 主要商品major equipment 主要设备major installation 主要设备key facility 主要设施main facility 主要设施principal auditor 主要审计师main crosscut 主要石门primary tense 主要时- 拉丁语、希腊语语法的leading market 主要市场primary market 主要市场- 证券发行principal market 主要市场staple market 主要市场main fact 主要事实primary fact 主要事实essential attribute 主要属性main feature 主要特点key architectural characteristics 主要体系特性key architectural feature 主要体系特性essential condition 主要条件mother gallery 主要通道- 昆虫巢中的leading currency 主要通货key statistic 主要统计量major investment projects 主要投资项目key breakthrough 主要突破principal drawback 主要退税退款main danger 主要危险性master file 主要文件primary pollution source 主要污染源major section terminal subcontrol 主要线段终端控制分站main project 主要项目major project 主要项目prime cost of sale 主要销售成本macronutrient 主要养分primary nutrient 主要养分key factor 主要因素principle factor 主要因素main bank 主要银行principal place of business 主要营业地main effect 主要影响concordance 主要语词索引major component 主要元件major casualty 主要灾害ultimate liability 主要责任primary liabilities 主要债务head book 主要帐簿main book 主要帐簿major book 主要帐簿principal book 主要帐簿main account 主要帐户major issue 主要争论点cardinal symptom 主要症状main executive 主要执行者major executive 主要执行者key post 主要职位chief group of occupation 主要职业组first charge 主要指控primary instruction 主要指令major installation 主要装置prime assets 主要资产prime meridian 主要子午线code name of main charter party 主要租船合同代号key component 主要组成部分major histocompatibility complex 主要组织相容性复合体MHC restriction 主要组织相容性复合体的限制性major offence 主要罪行home page 主页principal sheet 主页main page pool 主页池main pancreatic duct 主胰管primary constriction 主缢痕main plane 主翼面primary cause 主因principal factor 主因子principal factor method 主因子法principal factor solution 主因子解法main establishment 主营业所principal strain 主应变primary stress 主应力principal stress 主应力trajectory of principal stress 主应力轨线principal stress space 主应力空间principal axes of stresses 主应力轴principal stress axis 主应力轴primary application 主应用程序primary application block 主应用块principal mapping 主映射master user 主用户primary user disk 主用户磁盘main oil pump 主油泵main cylinder 主油缸main poise 主游铊principal right ideal 主右理想subject 主语host language 主语言host language compilation 主语言编译host language processor 主语言处理程序host language interface 主语言接口host language data base 主语言数据库host language system 主语言系统host language statement 主语言语句host language execution 主语言执行pivot 主元pivot element 主元principal element 主元素pivot selection 主元选择method of pivot selection 主元选择法pivot operation 主元运算primary circle 主圆principal circle 主圆master source program 主源程序primary source text 主源程序正文principal reduced form 主约化型main thermocline 主温跃层primary motion 主运动principle motion 主运动direction of primary motion 主运动方向main haulage 主运输大巷main haulage conveyor 主运输机gangway 主运输平巷main arithmetic processor 主运算处理机master factor 主宰因子main carrier 主载波primary plasticizer 主增塑剂master gain control 主增益控制prime liability 主债务principal debt 主债务principal obligation 主债务principal debtor 主债务人main stack frame 主栈框架main battle tank 主战坦克main station 主站master station 主站primary 主站primary station 主站primary-to-secondary flow 主站到次站数据流primary application 主站应用primary application program 主站应用程序principal tensor 主张量principal nutation 主章动major fold 主褶曲battle position 主阵地principal oscillation 主振荡master oscillator 主振荡器master oscillator power amplifier 主振功率放大器masterfrequency 主振频率main shock 主震major shock 主震main steam 主蒸汽principal normal complex 主正规复形principal normal section 主正截面main forward path 主正向通路principal branch 主枝main executive module 主执行程序模块principal value 主值main check valve 主止回阀master instruction tape 主指令带main instruction buffer 主指令缓冲器primary instruction pipeline 主指令流水线basic order code 主指令码principal exponent 主指数parenchyma 主质major dense line 主致密线major relay station 主中继站primary center 主中心局principal neutral point 主中心点main centre 主中心局master CPU 主中央处理机master central timing system 主中央计时系统master terminal 主终端master terminal key 主终端密钥master clock 主钟primary clock 主钟primary period 主周期principal period 主周期capstan 主轴arbor 主轴basic shaft 主轴caudex 主轴head shaft 主轴main axle 主轴main shaft 主轴pilot shaft 主轴principal axis 主轴quill 主轴rachis 主轴spindle 主轴principal axis transformation 主轴变换transformation of principal axis 主轴变换spindle unit 主轴部件bush neck 主轴衬base bearing 主轴承main bearing 主轴承spindle drive 主轴传动机构distance from spindle nose to central line of table 主轴端面至工作台中心线距离method of principal axis 主轴法main shaft distance bushing 主轴隔套spindle drum 主轴鼓轮spindle collar 主轴环principal axis solution 主轴解main journal 主轴颈spindle hole 主轴孔spindle bore 主轴孔径main shaft seal 主轴密封- 水轮机spindle face 主轴面main shaft angle 主轴倾角quill servo stroke 主轴伺服行程spindle speed function 主轴速度功能main shaft packing 主轴填料main shaft gland 主轴填料压盖spindle head 主轴头spindle nose 主轴头部external taper of spindle 主轴外锥primary axis 主轴线setting-out of main axis 主轴线测设headstock 主轴箱spindle carrier 主轴箱spindle head 主轴箱rapid traverse speed of headstock 主轴箱快移速度maximum travel of headstock 主轴箱最大行程travel of spindle 主轴行程basic shaft system 主轴制speed of main spindle 主轴转速speed of main shaft 主轴转速spindle speed 主轴转速range of spindle speeds 主轴转速范围number of spindle speeds 主轴转速级数taper hole of spindle 主轴锥孔minimum speed of spindle 主轴最低转速maximum speed of spindle 主轴最高转速spindle seat 主轴座dominant patent 主专利main patent 主专利master patent 主专利principle patent 主专利date of commencement of the main patent 主专利的开始日major relay center 主转换中心principal moment of inertia 主转动惯量main rotor 主转子king pile 主桩major state generator 主状态发生器major state logic generator 主状态逻辑发生器main cone 主锥inner cone angle 主锥角principal square submatrix 主子方阵principal minor array 主子矩阵principal subspace 主子空间prime subpool 主子库chief series of subgroups 主子群列leading minor 主子式minor in principal position 主子式principal minor 主子式principal meridian 主子午线master subsystem 主子系统principal automorphism 主自同构majority word 主字main group 主族major constituent 主组分principal maximum 主最大principal left ideal 主左理想principal coordinate 主坐标kier 煮布锅koktigen 煮沸疫苗cocoon cooking 煮茧cocoon cooking machine 煮茧机glue cooker 煮胶锅digestion 煮解digester 煮解器boiling-off 煮练bucking kier 煮练锅boiling house recovery 煮炼收回率boiling house efficiency 煮炼效率crabbing 煮呢boiling 煮呢crabbing machine 煮呢机boiling hole 煮生石灰坑water evaporator 煮水罐sugar boiling 煮糖vacuum pan 煮糖罐dosage for sugar boiling 煮糖配料pan-boiling system 煮糖系统boiling scheme 煮糖制度soap kettle 煮皂锅boiling of seed strike 煮种Boehmeria nivea Gaud. 苎麻China grass 苎麻ramie 苎麻ramie lining 苎麻衬布Paraglenea fortunei 苎麻天牛ramie 苎麻纤维Cocytodes coerulea 苎麻夜蛾ramie counts 苎麻支数ramie cloth 苎麻织物auxiliary saddle 助鞍boost 助爆midwife 助产士midwifery 助产学truster 助铲机- 铲运机的activating accelerator 助促进剂promoter 助催化剂auxiliary type gravimeter 助动型重力仪astatic gravimeter 助动重力仪jato unit 助飞装置nurse-root grafting 助根接secondary attack 助攻subsidiary attack 助攻scaling powder 助焊剂navaid 助航设备mnemonic coding 助记编码mnemonic variable name 助记变量名mnemonic operation code 助记操作码mnemonic programming language 助记符程序设计语言mnemonic address 助记地址mnemonic address code 助记地址码mnemonic system 助记忆方式。

bitlocker的⽂献翻译河南理⼯⼤学（本科）⽂献翻译Windows 7中Bitlocker驱动器加密常被问到的问题姓名：学号：专业：指导⽼师：BitLocker Drive Encryption in Windows 7: Frequently Asked QuestionsBitLocker Drive Encryption is a data protection feature available in Windows 7 Enterprise, Windows 7 Ultimate, and in all editions of Windows Server 2008 R2. This topic includes frequently asked questions about BitLocker in Windows 7.1、What is BitLocker? How does it work?BitLocker Drive Encryption is a data protection feature available in Windows 7 Enterprise and Windows 7 Ultimate for client computers and in Windows Server 2008 R2. BitLocker provides enhanced protection against data theft or exposure on computers and removable drives that are lost or stolen, and more secure data deletion when BitLocker-protected computers are decommissioned as it is much more difficult to recover deleted data from an encrypted drive than from a non-encrypted drive.2、How BitLocker works with operating system drivesData on a lost or stolen computer is vulnerable to unauthorized access, either by running a software attack tool against it or by transferring the computer's hard disk to a different computer. BitLocker helps mitigate unauthorized data access on lost or stolen computers by:Encrypting the entire Windows operating system drive on the hard disk. BitLocker encrypts all user files and system files on the operating system drive, including the swap files and hibernation files.Checking the integrity of early boot components and boot configuration data. On computers that have a Trusted Platform Module (TPM) version 1.2, BitLocker uses the enhanced security capabilities of the TPM to help ensure that your data is accessible only if the computer's boot components appear unaltered and the encrypted disk is located in the original computer.BitLocker is integrated into Windows 7 and provides enterprises with enhanced data protection that is easy to manage and configure. For example, BitLocker can use an existing Active Directory Domain Services (AD DS) infrastructure to remotely store BitLocker recovery keys.3、How BitLocker works with fixed and removable data drivesBitLocker can also be used to protect fixed and removable data drives. When used with data drives, BitLocker encrypts the entire contents of the drive and can be configured by using Group Policy to require that BitLocker be enabled on a drive before the computer can write data to the drive. BitLocker can be configured with the following unlock methods for data drives:Automatic unlock. Fixed data drives can be set to automatically unlock on a computer where the operating system drive is encrypted. Removable data drives can be set to automatically unlock on a computer running Windows 7 after the password or smart card is initially used to unlock the drive. However, removable data drives must always have either a password or smart card unlock method in addition to the automatic unlock method.Password. When users attempt to open a drive, they are prompted to enter their password before the drive will be unlocked. This method can be used with the BitLocker To Go Reader on computers running Windows Vista or Windows XP, to open BitLocker-protected drives as read-only.Smart card. When users attempt to open a drive, they are prompted to insert their smart card before the drive will be unlocked.A drive can support multiple unlock methods. For example, a removable data drive can be configured to be automatically unlocked on your primary work computer but query you for a password if used with another computer.4、Does BitLocker support multifactor authentication?Yes, BitLocker supports multifactor authentication for operating system drives. If you enable BitLocker on a computer that has a TPM version 1.2, you can use additional forms of authentication with the TPM protection. BitLocker offers the option to lock the normal boot process until the user supplies a personal identification number (PIN) or inserts a USB device (such as a flash drive) that contains a BitLocker startup key, or both the PIN and the USB device can be required. These additional security measures provide multifactor authentication and help ensure that the computer will not start or resume from hibernation until the correct authentication method is presented.备注：Use of both the USB and PIN along with the TPM must be configured by using the Manage-bde command-line tool. This protection method cannot be specified by using the BitLocker setup wizard.5、What are the BitLocker hardware and software requirements?To use all BitLocker features, your computer must meet the hardware and software requirements listed in the following table. Hardware configuration：The computer must meet the minimum requirements for Windows 7.Operating system：Windows 7 Ultimate, Windows 7 Enterprise, or Windows Server 2008 R2（备注：BitLocker is an optional feature of Windows Server 2008 R2. Use Server Manager to install BitLocker on a computer running Windows Server 2008 R2.）Hardware TPM：TPM version 1.2, A TPM is not required for BitLocker; however, only a computer with a TPM can provide the additional security of pre-startup system integrity verification and multifactor authentication.BIOS configuration：A Trusted Computing Group (TCG)-compliant BIOS. The BIOS must be set to start first from the hard disk, and not the USB or CD drives. The BIOS must be able to read from a USB flash drive during startup.File system：At least two NTFS disk partitions, one for the system drive and one for the operating system drive. The system drive partition must be at least 100 megabytes (MB) and set as the active partition.6、Why are two partitions required? Why does the system drive have to be so large?Two partitions are required to run BitLocker because pre-startup authentication and system integrity verification must occur on a separate partition from the encrypted operating system drive. This configuration helps protect the operating system and the information in the encrypted drive. In Windows Vista, the system drive must be 1.5 gigabytes (GB), but in Windows 7 this requirement has been reduced to 100 MB for a default installation. The system drive may also be used to store the Windows Recovery Environment (Windows RE) and other files that may be specific to setup or upgrade programs. Computer manufacturers and enterprise customers can also storesystem tools or other recovery tools on this drive, which will increase the required size of the system drive. For example, using the system drive to store Windows RE along with the BitLocker startup file will increase the size of the system drive to 300 MB. The system drive is hidden by default and is not assigned a drive letter. The system drive is created automatically when Windows 7 is installed.7、Which Trusted Platform Modules (TPMs) does BitLocker support?BitLocker supports TPM version 1.2. BitLocker does not support previous versions of TPMs. Version 1.2 TPMs provide increased standardization, security enhancement, and improved functionality over previous versions. In addition, you must use a Microsoft-provided TPM driver.注意事项：When using BitLocker with a TPM, it is recommended that BitLocker be turned on immediately after the computer has been restarted. If the computer has resumed from sleep prior to turning on BitLocker, the TPM may incorrectly measure the pre-boot components on the computer. In this situation, when the user subsequently attempts to unlock the computer, the TPM verification check will fail and the computer will enter BitLocker recovery mode and prompt the user to provide recovery information before unlocking the drive.8、How can I tell whether my computer has a TPM version 1.2?Click Start, click Control Panel, click System and Security, click BitLocker Drive Encryption, and then click Turn OnBitLocker. If your computer does not have a TPM version 1.2 or the BIOS is not compatible with the TPM, you will receive the following error message:A compatible Trusted Platform Module (TPM) Security Device must be present on this computer, but a TPM was not found. Please contact your system administrator to enable BitLocker.If you receive this error message on a computer that has a TPM, check if either of the following situations applies to your computer:Some computers have TPMs that do not appear in the Windows 7 TPM Microsoft Management Console snap-in (tpm.msc) due to a BIOS setting that hides the TPM by default and does not make the TPM available unless it is first enabled inthe BIOS. If your TPM might be hidden in the BIOS, consult the manufacturer's documentation for instructions to display or enable the TPM.Some computers might have an earlier version of the TPM or an earlier version of the system BIOS that is not compatible with BitLocker. Contact the computer manufacturer to verify that the computer has a TPM version 1.2 or to get a BIOS update.9、Can I use BitLocker on an operating system drive without a TPM version 1.2?Yes, you can enable BitLocker on an operating system drive without a TPM version 1.2, if the BIOS has the ability to read from a USB flash drive in the boot environment. This is because BitLocker will not unlock the protected drive until BitLocker's own volume master key is first released by either the computer's TPM or by a USB flash drive containing the BitLocker startup key for that computer. However, computers without TPMs will not be able to use the system integrity verification that BitLocker can also provide.To help determine whether a computer can read from a USB device during the boot process, use the BitLocker system check as part of the BitLocker setup process. This system check performs tests to confirm that the computer can properly read from the USB devices at the appropriate time and that the computer meets other BitLocker requirements.To enable BitLocker on a computer without a TPM, you must enable the “Require additional authentication at setup” Group Policy setting, which is located in Computer Configuration\Administrative Templates\Windows Components\BitLocker Drive Encryption\Operating System Drives”. You must select the “Allow BitLocker without a compatible TPM “check box. After this setting is applied to the local computer, the non-TPM settings appear in the BitLocker setup wizard.10、How do I obtain BIOS support for the TPM on my computer?Contact the computer manufacturer to request a Trusted Computing Group (TCG)-compliant BIOS. Ensure that the BIOS meets the following requirements:1、I t is compatible with Windows 7 and has passed the Windows 7 logo tests.2、I t is compliant with the TCG standards for a client computer.3、I t has a secure update mechanism to help prevent a malicious BIOS frombeing installed on the computer.11、What credentials are required to use BitLocker?To turn on, turn off, or change configurations of BitLocker on operating system and fixed data drives, membership in the local Administrators group is required. Standard users can turn on, turn off, or change configurations of BitLocker on removable data drives.12、What versions of Windows 7 include BitLocker? Can I use BitLocker on a Windows XP–based computer?BitLocker is available in Windows 7 Ultimate and Windows 7 Enterprise. However, you can unlock encrypted removable drives on any version of Windows 7. BitLocker is not available in Windows XP, but you can use the BitLocker To Go Reader to view content on BitLocker-protected removable drives from a computer running Windows XP.13、What is the difference between disabling, suspending, and decrypting when I turn off BitLocker?Decrypt completely removes BitLocker protection and fully decrypts the drive.Disable and Suspend refer to the same process. Disable was used in Windows Vista, and Suspend is used in Windows 7. The term was changed to more accurately describe the process. When BitLocker is suspended, BitLocker keeps the data encrypted but encrypts the BitLocker volume master key with a clear key. The clear key is a cryptographic key storedunencrypted and unprotected on the disk drive. By storing this key unencrypted, the Suspend option allows for changes or upgrades to the computer without the time and cost of decrypting and re-encrypting the entire drive. After the changes are made and BitLocker is again enabled, BitLocker will reseal the encryption key to the new values of the measured components that changed as a part of the upgrade, and the clear key is erased. This option is only available for operating system drives.14、Do I have to decrypt my BitLocker-protected drive to download and install system updates and upgrades?Operating system upgrades from Windows Anytime Upgrade require that the operating system drive be decrypted prior to installation. If you upgrade fromWindows Vista to Windows 7 or install other non-Microsoft updates, you might need to disable or suspend BitLocker so that a new measurement of the system can be taken after the upgrade or update has been applied. Software and operating system updates from Microsoft Update do not require drive decryption or that you disable or suspend BitLocker.备注Disable is the term used in Windows Vista to refer to the process of temporarily suspending BitLocker protection on a drive without decrypting the drive. In Windows 7, the term has been changed to Suspend to more accurately reflect the process.Please refer to the following table to determine whether you must disable or suspend BitLocker or decrypt your drive before you perform an upgrade or updateIf you disabled or suspended BitLocker, you can resume BitLocker protection after you have installed the upgrade or update. Upon resuming protection, BitLocker will reseal the encryption key to the new values of the measured components that changed as a part of the upgrade or update. If these types of upgrades or updates are applied without decrypting or disabling BitLocker, your computer will enter recovery mode when restarting and will require a recovery key or password to access the computer.15、Can BitLocker encrypt more than just the operating system drive?Yes. In Windows 7, BitLocker can encrypt operating system drives, fixed data drives, and removable data drives.16、Is there a noticeable performance impact when BitLocker is enabled on a Windows 7–based computer?Generally it imposes a single-digit percentage performance overhead.17、Approximately how long will initial encryption take when BitLocker is turned on?BitLocker encryption occurs in the background while you continue to work, and the system remains usable, but encryption times vary depending on the type of drive that is being encrypted, the size of the drive, and the speed of the drive. If you are encrypting very large drives, you may want to set encryption to occur during times when you will not be using the drive.18、What happens if the computer is turned off during encryption or decryption?If the computer is turned off or goes into hibernation, the BitLocker encryption and decryption process will resume where it stopped the next time Windows starts. This is true even if the power is suddenly unavailable.19、Why does it appear that most of the free space in my drive is used when BitLocker is converting the drive?BitLocker cannot ignore free space when the drive is being encrypted because unallocated disk space commonly contains data remnants. However, it is not efficient to encrypt free space on a drive. To solve this problem, BitLocker first creates a large placeholder file that takes most of the available disk space and then writes cryptographic material to disk sectors that belong to the placeholder file. During this process, BitLocker leaves 6 GB of available space for short-term system needs. All other space, including the 6 GB of free space not occupied by the placeholder file, is encrypted. When encryption of the drive is paused or completed, the placeholder file is deleted and the amount of available free space reverts to normal. A placeholder file is used only on drives formatted by using the NTFS or exFAT file system.If you want to reclaim this free space before encryption of the drive has completed, you can use the Manage-bde command-line tool to pause encryption.20、Does BitLocker encrypt and decrypt the entire drive all at once when reading and writing data?No, BitLocker does not encrypt and decrypt the entire drive when reading and writing data. The encrypted sectors in the BitLocker-protected drive are decrypted only as they are requested from system read operations. Blocks that are written to the drive are encrypted before the system writes them to the physical disk. No unencrypted data is ever stored on a BitLocker-protected drive.21、How can I prevent users on a network from storing data on an unencrypted drive?In Windows 7, you can enable Group Policy settings to require that data drives be BitLocker-protected before a BitLocker-protected computer can write data to them. The policy settings you use for this are:Computer Configuration\Administrative Templates\Windows Components \B-itLocker Drive Encryption\Fixed DataDrives\Deny write access to fixed drives not protected by BitLocker.Computer Configuration\Administrative Templates\Windows Components\Bit-Locker Drive Encryption\Removable Data Drives\Deny write access to removab-le drives not protected by BitLocker.When these policy settings are enabled, the BitLocker-protected operating system will mount any data drives that are not protected by BitLocker as read-only.If you are concerned that your users might inadvertently store data in an unencrypted drives while using a computer that does not have BitLocker enabled, use access control lists (ACLs) and Group Policy to configure access control for the drives or hide the drive letter.22、What system changes would cause the integrity check on my operating system drive to fail?The following types of system changes can cause an integrity check failure and prevent the TPM from releasing the BitLocker key to decrypt the protected operating system drive:Moving the BitLocker-protected drive into a new computer.Installing a new motherboard with a new TPM.Turning off, disabling, or clearing the TPM.Changing any boot configuration settings.Changing the BIOS, master boot record, boot sector, boot manager, option ROM, or other early boot components or boot configuration data.This functionality is by design; BitLocker treats unauthorized modification of any of the early boot components as a potential attack and will place the system into recovery mode. Authorized administrators can update boot components without entering recovery mode by disabling BitLocker beforehand.23、What causes BitLocker to start into recovery mode when attempting to start the operating system drive?The following list provides examples of specific events that will cause BitLocker to enter recovery mode when attempting to start the operating system drive: Changing any boot configuration data (BCD) boot entry data type settings .Changing the BIOS boot order to boot another drive in advance of the hard drive.Having the CD or DVD drive before the hard drive in the BIOS boot order and then inserting or removing a CD or DVD.Failing to boot from a network drive before booting from the hard drive.Changes to the NTFS partition table on the disk including creating, deleting, or resizing a primary partition.Entering the personal identification number (PIN) incorrectly too many times so that the anti-hammering logic of the TPM is activated..Turning off the BIOS support for reading the USB device in the pre-boot environment if you are using USB-based keys instead of a TPM.Turning off, disabling, or clearing the TPM.Upgrading critical early startup components, such as a BIOS upgrade, causing the BIOS measurements to change. Forgetting the PIN when PIN authentication has been enabled.Adding or removing hardware. For example, inserting a new card in the computer, including some PCMIA wireless cards. 24、Can I swap hard disks on the same computer if BitLocker is enabled on the operating system drive?Yes, you can swap multiple hard disks on the same computer if BitLocker is enabled, but only if the hard disks were BitLocker-protected on the same computer. The BitLocker keys are unique to the TPM and operating system drive, so if you want to prepare a backup operating system or data drive for use in case of disk failure, you need to make sure that they were matched with the correct TPM. You can also configure different hard drives for different operating systems and then enable BitLocker on each one with different authentication methods (such as one with TPM-only and one with TPM+PIN) without any conflicts.25、Can I access my BitLocker-protected drive if I insert the hard disk into a different computer?Yes, if the drive is a data drive, you can unlock it from the BitLocker Drive Encryption Control Panel item just as you would any other data drive by using a password or smart card. If the data drive was configured for automatic unlock only, you will have to unlock it by using the recovery key. If it is an operating system drive mounted on another computer running Windows 7, the encrypted hard disk can be unlocked by a data recovery agent if one was configured or it can be unlocked by26、Why is "Turn BitLocker on" not available when I right-click a drive?Some drives cannot be encrypted with BitLocker. Reasons a drive cannot be encrypted include insufficient disk size, an incompatible file system, or a drive is designated as the system partition. By default, the system drive (or system partition) of a computer running Windows 7 is hidden from display in the Computer window. However, if it is not created as a hidden drive when the operating system was installed due to a custom installation process, that drive might be displayed but cannot be encrypted.27、What is the difference between a TPM owner password, recovery password,recovery key, PIN, enhanced PIN, and startup key?There are multiple keys that can be generated and used by BitLocker. Some keys are required and some are optional protectors you can choose to use depending on the level of security you require.TPM owner passwordPrior to enabling BitLocker on a computer with a TPM version 1.2, you must initialize the TPM. The initialization process generates a TPM owner password, which is a password set on the TPM. Recovery password and recovery key When you set up BitLocker, you must choose how access to BitLocker-protected drives can be recovered in the event that the specified unlock method cannot be used (such as if the TPM cannot validate the boot components, the personal identification number (PIN) is forgotten, or the password is forgotten). In these situations, you must be able to supply either the recovery key or the recovery password to unlock the encrypted data on the drive. In Windows 7, the term "recovery key" is used generically to refer to both the recovery key file and the recovery password. When you supply the recovery information, you can use eitherof the following formats:A recovery password consisting of 48 digits divided into eight groups. During recovery, you need to type this password into the BitLocker recovery console by using the function keys on your keyboard.A key file on a USB flash drive that is read directly by the BitLocker recovery console. During recovery, you need to insert this USB device. PIN and enhanced PINFor a higher level of security with the TPM, you can configure BitLocker with a personal identification number (PIN). The PIN is a user-created value that must be entered each time the computer starts or resumes from hibernation. The PIN can consist of 4 to 20 digits as specified by the Configure minimum PIN length for startup Group Policy setting and is stored internally as a 256-bit hash of the entered Unicode characters. This value is never displayed to the user. The PIN is used to provide another factor of authentication in conjunction with TPM authentication.For an even higher level of security with the TPM, you can configure BitLocker to use enhanced PINs. Enhanced PINs are PINs that use the full keyboard characterset in addition to the numeric set to allow for more possible PIN combinations and are between 4 and 20 characters in length. To use enhanced PINs, you must enable the Allow enhanced PINs for startup Group Policy setting before adding the PIN to theWhen setting a BitLocker PIN by using the BitLocker setup wizard, the Manage-bde command-line tool, or through Windows Management Instrumentation (WMI) remote administration, you can use the wide character set. However, system firmware, either BIOS or Unified Extensible Firmware Interface (UEFI), may only support a standard EN-US keyboard and keymap during system startup. Additionally, BIOS-based systems are limited to 7-bit ASCII input during PIN entry. Thus, the use of either non-English characters or keys that differ in position from the EN-US keymap, such as QWERTZ and AZERTY keyboards, may cause boot-time PIN entry to fail. If your computer is affected by this limitation, it should be identified during the system check run by the BitLocker setup wizard. If it is not identified during the system check and the PIN is not able to be entered, you will need to supply the recovery key to unlock the drive.Startup keyConfiguring a startup key is another method to enable a higher level of security with the TPM. The startup key is a key stored on a USB flash drive, and the USB flash drive must be inserted every time the computer starts. The startup key is used to provide another factor of authentication in conjunction with TPM authentication. To use a USB flash drive as a startup key, the USB flash drive must be formatted by using the NTFS, FAT, or FAT32 file system.重要事项:You must have a startup key to use BitLocker on a non-TPM computer.28、How can the recovery password and recovery key be stored?The recovery password and recovery key for an operating system drive or a fixed data drive can be saved to a folder, saved to one or more USB devices, or printed.For removable data drives, the recovery password and recovery key can be saved to a folder or printed. By default, you cannot store a recovery key for a removable drive on a removable drive.A domain administrator can additionally configure Group Policy to automatically generate recovery passwords and store them in Active Directory Domain Services (AD DS) for any BitLocker-protected drive.29、If I lose my recovery information, will the BitLocker-protected data be unrecoverable?BitLocker is designed to make the encrypted drive unrecoverable without the required authentication. When in recovery mode, the user needs the recovery password or recovery key to unlock the encrypted drive. Therefore, we highly recommend that you store the recovery information in AD DS or in another safe location.30、Can the USB flash drive that is used as the startup key also be used to store the recovery key?While this is technically possible, it is not a best practice to use one USB flash drive to store both keys. If the USB flash drive that contains your startup key is lost or stolen, you also lose access to your recovery key. In addition, inserting this key would cause your computer to automatically boot from the recovery key even if TPM-measured files have changed, which circumvents the TPM's system integrity check.31、Can I save the startup key on multiple USB flash drives?Yes, you can save a computer's startup key on multiple USB flash drives. Right-clicking a BitLocker-protected drive and selecting Manage BitLocker will provide you the options to duplicate the recovery keys as needed.32、Can I save multiple (different) startup keys on the same USB flash drive?Yes, you can save BitLocker startup keys for different computers on the same USB flash drive.33、Can I generate multiple (different) startup keys for the same computer?You can generate different startup keys for the same computer through scripting. However, for computers that have a TPM, creating different startup keys prevents BitLocker from using the TPM's system integrity check.34、What encryption keys are used in BitLocker? How do they work together?Raw data is encrypted with the full volume encryption key, which is then encrypted with the volume master key. The volume master key is in turn encrypted by one of several possible methods depending on your authentication (that is, key protectors or TPM) and recovery scenarios.35、Where are the encryption keys stored?The full volume encryption key is encrypted by the volume master key and stored in the encrypted drive. The volume master key is encrypted by the appropriate key protector and stored in the encrypted drive. If BitLocker has been suspended, the clear key that is used to encrypt the volume master key is also stored in the encrypted drive, along with the encrypted volume master key.This storage process ensures that the volume master key is never stored unencrypted and is protected unless you disable BitLocker. The keys are also saved to two additional locations on the drive for redundancy. The keys can be read and processed by the boot manager.36、Why do I have to use the function keys to enter the PIN or the 48-character recovery password?The F1 through F10 keys are universally mapped scan codes available in the pre-boot environment on all computers and in all languages. The numeric keys 0 through 9 are not usable in the pre-boot environment on all keyboards.When using an enhanced PIN, users should run the optional system check during the BitLocker setup process to ensure that the PIN can be entered correctly in the pre-boot environment.37、What is BitLocker To Go?BitLocker To Go is BitLocker Drive Encryption on removable data drives. Thisincludes the encryption of USB flash drives, SD cards, external hard disk drives, and other drives formatted by using the NTFS, FAT16, FAT32, or exFAT file systems. 38、How can I authenticate or unlock my removable data drive?In Windows 7, you can unlock removable data drives by using a password or a smart card. After you've started encryption, the drive can also be automatically unlocked on a specific computer for a specific user account. System administrators can configure which options are available for users, as well as password complexity and minimum length requirements.39、Can I use BitLocker To Go with computers running Windows XP or Windows Vista?Yes. By default if the removable data drive is formatted by using the FAT file system and then locked with BitLocker To Go using a computer running Windows 7, it can be unlocked on a computer running Windows XP or Windows Vista. However,。

附录ACircuit BreakerControl and selection of the circuit breakerCircuit breaker control mode selection and control mode of substation, the size of the substation and other factors. Substation control mode is different, different size, circuit breaker control mode also vary accordingly.According to the working voltage of control circuit, the circuit breaker control mode can be divided into two kinds of, heavy current and weak current control. According to the operation mode, can be divided into one control two kinds of control and line selection.So-called high voltage control, is from the control equipment of commands to the circuit breaker operating mechanism, the working voltage of the control circuit for dc 110 v or 220 v. According to the control site, divided into two kinds of centralized control and local control; According to the jump, switching circuit monitoring, divided into two kinds of lighting monitoring and audio surveillance; According to the connection of control circuit is divided into control switch has a fixed position is not corresponding to the connection with control switch contact automatic reset.Weak current control can be divided into the following two cases.(1) the working voltage of circuit breaker control circuit into two parts, low voltage and heavy current issue commands control equipment is working voltage weak current is usually 48 v. Command is issued, and then through the middle and weak electricity conversion link weak current signal conversion to high voltage signal, command, to the circuit breaker operating mechanism. Intermediate conversion links between circuit breaker and at the same structure and high voltage control circuit. This weak current control, is essentially the layout on the control panel of weak electrochemical control equipment.(2) from the control equipment to the working voltage of circuit breaker operating mechanism of all circuits are all elv. This way of command signal transmission distance is relatively close, the circuit breaker operation and power is large, it is not suitable for 220500 kv substation.Low voltage line selection control wiring is more complex, more operation steps, hard to ensure its reliability. 220-500 kv substation circuit breaker, do not recommend using low voltage line selection control.Common characteristic is due to the weak current control on the control panel using the miniaturization of the weak current control device, the control panel on the unit area can be assigned by the control loop. Under the condition of same number of controlled object, compared with the high voltage control, can reduce the area of the control panel, convenient monitoring and operational personnel; Reduced the master control room construction area, reduce the investment in civil engineering. This is a major advantage of the weak current control. But weak current equipment there is insufficient, low voltage terminal and weak current equipment of electrical insulation distance is small, be afraid of dust, especially under the condition of dust containing conductive material more dangerous; Weak current equipment terminals and screen after the weak current connection terminals and soft line connection with welding, due to close the distance between the terminal, when check line and cleaning pay special attention to prevent short circuit between terminals; In addition, there is low mechanical strength, off contact capacity small, poor anti-jamming performance shortcomings.High voltage control can be divided into high voltage one to one direct control and high voltage line selection control. Very few of the latter in the practical engineering applications. High voltage one to one direct control method has simple control circuit, power supply voltage of a single operation, the operation personnel easy to grasp, convenient maintenance, high reliability advantages, all kinds of used in substation is put into operation a major control method.High voltage control, because of the working voltage of control equipment is higher, to meet the requirements of insulation distance, control equipment, terminalequipment such as the volume is big, and within the unit area on the control panel can decorate less control goes back from them. In substation scale, more cases of the object, and the control panel. This not only increases the surface area of the main control room, increasing the cost of civil engineering, at the same time, due to the large surveillance plane, is unfavorable to the normal monitoring and operation.At present, the control method is: one to one direct control, station is not a conventional control panel, control was achieved by independent measurement device. The old station is also gradually according to the methods of modification.When in breaker control circuit design should pay attention to the following basic requirements.(1) shall have the monitoring circuit of the control power. Circuit breaker control power is the most important, once lost power supply, circuit breaker can't operate. Whatever the reason, therefore, when the circuit breaker control power supply disappears, should sound and light signals, prompt the personnel on duty timely processing.(2) should be regularly monitored circuit breaker jump, switching circuit integrity, when tripping or switching circuit malfunction, should signal circuit breaker control circuit disconnection.(3) should be prevent electric lock circuit breaker "jump", "jump" to the circuit breaker is very dangerous, easy to cause body damage, even caused an explosion of the circuit breaker, so blocking measures must be taken. At present, the microcomputer protection device and the operation of the circuit breaker loop in the default configuration, have prevent breaker "jump" electrical circuits. Practical application, use and can only use one to prevent the circuit breaker electric circuits of the "jump". Design and operation, should strictly for manufacturer to design the part of the circuit.On February 2, 1997, 220 kv line A phase fault of A certain power plant, line on both sides of the right protection device, but when reclosing circuit breaker are produced on both sides "jump" phenomenon. Among them, the power plant side of circuit breaker open final in a row, hydraulic fell sharply, circuit breaker stay in usafter rejected points. Due to the fault point not resection, the 220 kv circuit breaker failure protection action will bus coupler circuit breaker and all components of resection, on a bus a bus power outages. Accident examination revealed: fault line of the power plant side split-phase operation box, keep the coil spring prevention relay voltage polarity reverse, defend jump circuit fails to play a role, to cause the circuit breaker "jump" phenomenon: the client is due to its anti jump in the relay coil short-circuit current, and lead to defend jump circuit fails to play a role.Circuit breaker "jump" phenomenon is generally tripping and closing loop through to occurs at the same time. "Jump" prevention circuit design should make there was a "jump" circuit breaker, the circuit breaker lockout to trip position.(4) jump, closing orders should be long enough, and when the tripping or closing, after the completion of the command pulse should be able to remove automatically. Usually consists of circuit breaker auxiliary contacts automatically disconnect jump, switching circuit.(5) for circuit breaker jump, switching state, should have a clear position signal, fault automatic tripping, automatic switching, should have obvious action signal.(6) the operation of the circuit breaker dynamic disappear or inadequate, for example, spring spring not taut, hydraulic or pneumatic pressure to reduce, etc., should be closed circuit breaker action, and a signal; SF6 gas insulated circuit breaker, when the SF6 gas pressure drops and circuit breaker cannot be reliable operation, should also blocking the action of circuit breaker, and a signal.In the case of lines or transformers trouble-free, pressure reduce atresia trip circuit. If you don't locking at this time, once a line or transformer failure, due to the circuit breaker pressure has been reduced, the main contactor has no arc suppression ability, may cause the circuit breaker explosion and its consequence is unimaginable.(7) under the condition of meet the above requirements, makes every effort to control circuit wiring is simple, the equipment and use the least amount of cable.附录B断路器控制方式及选择断路器的控制方式选择与变电所的控制方式、变电所的规模等因素有关。

1.パスワード：密码，来源自英文“password”。

例：パスワードを入力する。

/ 输入密码。

画面から取得されたパスワードはテーブルに格納します。

/ 从画面上取得的密码存在表中。

2. ユーザー：用户。

来源自英文“user”。

例：これはユーザーの情報を表示する機能です。

/ 这是表示用户信息的功能。

画面からユーザー名を入力してください。

/ 请在画面上输入用户名。

3. ログ゗ン：登录，注册。

来源自英文“log in”。

例：ユーザー名とパスワードを入力してから、ログ゗ンできます。

/ 输入用户名和密码后可以登录。

ログ゗ン画面では、エラーメッセージを表示します。

/ 在登录显示错误信息。

4. レ゗ゕウト：布局。

来源自英文“layout”。

例：画面レ゗ゕウトが間違っています。

/ 画面布局有错误。

画面レ゗ゕウトは仕様書と一致してください。

/ 请保持画面布局与式样书一致。

5. 引数（ひきすう）：参数。

例：A引数の内容は仕様書を参照ください。

/ 参数A的内容请参见式样书。

A引数をBメソッドに引き渡します。

/ 将参数A传给B方法。

6. 更新——こうしん更新例：更新データフゔ゗ルを読み込み、情報テーブルの更新を行う。

/读取更新数据文件，进行情报表的更新。

取得したデータはテーブルに更新してください。

/请将取得的数据更新到表中。

7. 格納——かくのう保存例：異常データはエラー詳細テーブルに格納する。

/异常数据保存到错误详细表中。

格納場所はありません。

/没有保存场所。

8. 編集——へんしゅう编辑例：「A：B」形式に編集する。

/编辑为「A：B」的形式。

編集結果はメールで教えてください。

/请通过MAIL告知编辑结果。

9. 押下——おうか按下例：入力内容をクリゕする場合、クリゕボタンを押下する。

/清空输入内容时，按下CLEAR 按钮。

クリゕした時に、エラーになった。

/清空时报错了。

10. 遷移——せんい跳转正常の場合は登録確認画面に遷移する。

1.This electron beam sweeps across each line at a uniform rate，then flies back to scan another line directly below the previous one and so on，until the horizontal lines into which it is desired to break or split the picture have been scannedin the desired sequence．电子束以均匀的速率扫描每一行，然后飞速返回去扫描下一行，直到把被扫描的图像按所希望的顺序分割成行。

2.The technical possibilities could well exist，therefore，of nation-wide integrated transmission network of high capacity，controlled by computers，interconnected globally by satellite and submarine cable，providing speedy and reliable communications throughout the word因此，在技术上完全可能实现全国性的集成发送网络。

这种网络容量大，由计算机控制，并能通过卫星和海底电缆实现全球互联，提供世界范围的高速、可靠的通信。

3.Transit time is the primary factor which limits the ability of a transistor to operate at high frequency．渡越时间是限制晶体管高频工作能力的主要因素4.The intensity of sound is inversely proportional to the square of the distance measured from the source of the sound.声强与到声源的距离的平方成反比。

毕业设计（论文）文献翻译英文资料：Computer Networks and DatabaseworksSome reasons are causing centralized computer systems to give way to networks.The first one is that many organizations already have a substantial number of computers in operation ,often located far apart .Initially ,each of these computers may have worked in isolation from the other ones ,but at a certain time ,management may have decided to connect them to be able to correlate information about the entire organization .Generally speaking ,this goal is to make all programs ,data ,and other resources available to anyone on the network without regard to the physical location of the resource and the user .The second one is to provide high reliability by having alternative sources of supply .With a network ,the temporary loss of a single computer is much less serious ,because its users can often be accommodated elsewhere until the service is restored .Yet another reason of setting up a computer network is computer network can provide a powerful communication medium among widely separated people .Application of NetworksOne of the main areas of potential network sue is access to remote database .It may someday be easy for people sitting at their terminals at home to make reservations for airplanes trains , buses , boats , restaurants ,theaters ,hotels ,and so on ,at anywhere in the world with instant confirmation .Home banking ,automated newspaper and fully automated library also fall in this category .Computer aided education is another possible field for using network ,with many different courses being offered.Teleconferencing is a whole new form communication. With it widely separated people can conduct a meeting by typing messages at their terminals .Attendees may leave at will and find out what they missed when they come back .International contacts by human begin may be greatly enhanced by network based communication facilities .Network StructureBroadly speaking,there are two general types of designs for the communication subnet:(1)Point –to –point channels(2)Broadcast channelsIn the first one ,the network contains numerous cables or lesased telephone lines ,each one connecting a pair of nodes .If two nodes that do not share a cablewish to communicate ,they must do this indirectly via other nodes .When a message is sent from node to another via one or more inter mediate modes ,each intermediate node will receive the message and store it until the required output line is free so that it can transmit the message forward .The subnet using this principle is called a point –to –piont or store –and –forward subnet .When a point –to –point subnet is used ,the important problem is how to design the connected topology between the nodes .The second kind of communication architecture uses broadcasting.In this design there is a single communication channel shared by all nodes .The inherence in broadcast systems is that messages sent by any node are received by all other nodes .The ISO Reference ModelThe Reference Model of Open System Interconnection (OSI),as OSI calls it ,has seven layers .The major ones of the principles ,from which OSI applied to get the seven layers ,are as follows:(1)A layer should be created where a different level of abstraction is needed.(2)Each layer should perform a well defined function .(3)The function of each layer should be chosen with an eye toward defininginternationally standardized protocols.(4)The layer boundaries should be chosen to minimize the information flow acrossthe interfaces .(5)The number of layers should be large enough so that distinct need not be puttogether in the same layer without necessity ,and small enough so that the architecture will not become out control .The Physical LayerThe physical layer is concerned with transmitting raw bits over a communication channel .Typical questions here are how many volts shoule be used to represent an 1 and how many a 0,how many microseconds a bit occupies ,whether transmission may proceed simultaneously in both are finished ,how to establish the initial connection and what kind of function each pin has .The design issues here largely deal with mechanical ,electrical and procedural interfacing to the subnet .The data link layerThe task of the data link layer is to obtain a raw transmission facility and to transform it into a line that appears free of transmission errors to the network layer .It accomplishes this task by breading the input data up into dataframes ,transmitting the frames sequentially ,and processing the acknowledgment frames sent back the receiver .Since the physical layer merely accepts and transmits a stream of bits without any regard to meaning or structure ,it can create and recognize frame boundaries until the data link layer .This can be accomplished by attaching special bits patterns to the beginning and the end of the frame .But it produce two problems :one is a noise burst on the line can destroy a frame completely .In this case ,the software in the source machine must retransmit the frame .The other is that some mechanismmust be employed to let the transmitter know how much buffer space the receiver has at the moment .The network layerThe network layer controls the operation of subnet .It determines the chief characteristics of the node-host interface ,and how packets ,the units of information exchanged in this layer ,are routed within the subnet .What this layer if software does ,basically ,is to accept messages from the source host ,convert them to packets ,and observe the packets to get the destination .The key design issue is how the route is determined .It could not only base on static table ,either are “wired into”the network and rarely changed ,by also adopt highly dynamic manner ,which can determine packet again to reflect the current network load .The transport layerThe basic function of transport layer is to accept data from the session layer ,split it up into smaller units ,if necessary ,pass these to the network layer ,and ensure that the pieces all arrive correctly at the other end .This layer is a true end-to-end layer .In other words ,a program on the source machine carries on a convene station with as similar program on the destination machine , using the message header and control messages .The session layerWith the session layer , the user must negotiate to establish a connection with a process on another machine .The connection is usually called a session. A session might be used to allow a user to log into a remote time-sharing system or to transfer a file between two machines .The operation of setting up a session between two processes is often called binding .Another function of the session layer is to manage the session once it has been setup .The presentation layerThe presentation layer could be designed to accept ASCⅡstrings as input and produce compressed bit patterns as output .This function of the presentation layer is called text compression .In addition ,this layer can also perform other trans formations .Encryption provide security is one possibility .Conversion between character codes ,such as ASCⅡto EBCDIC,might often be useful .More generally ,different computers usually have incompatible file formats ,so a file conversion option might be useful at times .The application layerMany issues occur here .For example ,all the issues of network transparency ,hiding the physical distribution of resources from user .Another issue is problem partitioning :how to divide the problem among the various machine in order to take maximum advantage of the network .2.Database systemThe conception used for describing files and databases has varied substantially in the same organization .A database may be defined as a collection of interrelated data stored together with as little redundancy as possible to serve one or more applications in an optimal fashion ;the data are stored so that they are independent of programs which use the data ;a common and retrieving existing data within the databases if they are entirely separate in structure .A database may be designed for batch processing ,real-time processing ,or in-line processing .A database system involve application program ,DBMS ,and database.One of the most important characteristics of most databases is that they will constantly need to change and grow .Easy restructuring of the database must be possible as new data types and new applications are added .The restructuring should be possible without having to rewrite the ap0plication program and in general should cause as little upheaval as possible .The ease with which a database can be changed will have a major effect on the rate at which data-processing can be developed in a corporation .The tem data independence is often quoted as being one of the main attributes of a data base .It implies that the data and the application programs which use them are independent so that either may be changed without changing the other .When a single set of data items serves a variety of applications ,different application programs perceive different relationships between the data items .To a large extent ,data-base organization is concerned with the representation between the data item about which we store information referred to as entities .An entity may be a tangible object or nontangible .It has various properties which we may wish to record .It can describes the real world .The data item represents an attribute ,and the attribute must be associated with the relevant entity .We design values to the attributes ,one attribute has a special significance in that it identifies the entity .An attribute or set of attributes which the computer uses to identify a record or tuple is referred to as a key .The primary key is defined as that key used to uniquely identify one record or tuple .The entity identifier consisting of one or more attributes .The primary key is of great importance because it is used by the computer in locating the record or tuple by means of an index or addressing algorithm .If the function of a data base were merely to store data ,its organization would be simple .Most of the complexities arise from the fact that is must also show the relationships between the various items of data that are stored .It is different to describe the data in logical or physical .The logical data base description is referred to as a schema .A schema is a chart of the types of data that one used .It gives the entities and attributes ,and specifics the relations between them .It is formwork into which the values of the data-items can be fitted .We must distinguish between a record type and a instance of the record .When we talk about a “personnel record”,this is really a record typed .There are no data vales associated with it .The term schema is used to mean an overall chart of all of the data-types and record types stored in a data base .The term subschema refers to an application programmer’s view of the data he uses .Many different sub schemas can be derived from one schema .The schema and the subschema are both used by the data-base management system ,the primary function of which is to serve the application programs by executing their data operations .A DBMS will usually be handing multiple data calls concurrently .It must organize its system buffers so that different data operations can be in process together .It provides a data definition language to specify the conceptual schema and most likely ,some of the details regarding the implementation of the conceptual schema by the physical schema .The data definition language is a high-level language ,enabling one to describe the conceptual schema in terms of a “data model”.The choice of a data model is a difficult one ,since it must be rich enough in structure to describe significant aspects of the real world ,yet it must be possible to determine fairly automatically an efficient implementation of the conceptual schema by a physical schema .It should be emphasized that while a DBMS might be used to build small data bases ,many data bases involve millions of bytes ,and an inefficient implementation can be disastrous .We will discuss the data model in the following and the .NET Framework is part of Microsoft's overall .NET framework, which contains a vast set of programming classes designed to satisfy any conceivable programming need. In the following two sections, you learn how fits within the .NET framework, and you learn about the languages you can use in your pages.The .NET Framework Class LibraryImagine that you are Microsoft. Imagine that you have to support multiple programming languages—such as Visual Basic, JScript, and C++. A great deal of the functionality of these programming languages overlaps. For example, for each language, you would have to include methods for accessing the file system, working with databases, and manipulating strings.Furthermore, these languages contain similar programming constructs. Every language, for example, can represent loops and conditionals. Even though the syntax of a conditional written in Visual Basic differs from the syntax of a conditional written in C++, the programming function is the same.Finally, most programming languages have similar variable data types. In most languages, you have some means of representing strings and integers, for example. The maximum and minimum size of an integer might depend on the language, but the basic data type is the same.Maintaining all this functionality for multiple languages requires a lot of work. Why keep reinventing the wheel? Wouldn't it be easier to create all this functionality once and use it for every language?The .NET Framework Class Library does exactly that. It consists of a vast set of classes designed to satisfy any conceivable programming need. For example, the .NET framework contains classes for handling database access, working with the file system, manipulating text, and generating graphics. In addition, it contains more specialized classes for performing tasks such as working with regular expressions and handling network protocols.The .NET framework, furthermore, contains classes that represent all the basic variable data types such as strings, integers, bytes, characters, and arrays.Most importantly, for purposes of this book, the .NET Framework Class Library contains classes for building pages. You need to understand, however, that you can access any of the .NET framework classes when you are building your pages.Understanding NamespacesAs you might guess, the .NET framework is huge. It contains thousands of classes (over 3,400). Fortunately, the classes are not simply jumbled together. The classes of the .NET framework are organized into a hierarchy of namespaces.ASP Classic NoteIn previous versions of Active Server Pages, you had access to only five standard classes (the Response, Request, Session, Application, and Server objects). , in contrast, provides you with access to over 3,400 classes!A namespace is a logical grouping of classes. For example, all the classes that relate to working with the file system are gathered together into the System.IO namespace.The namespaces are organized into a hierarchy (a logical tree). At the root of the tree is the System namespace. This namespace contains all the classes for the base data types, such as strings and arrays. It also contains classes for working with random numbers and dates and times.You can uniquely identify any class in the .NET framework by using the full namespace of the class. For example, to uniquely refer to the class that represents a file system file (the File class), you would use the following:System.IO.FileSystem.IO refers to the namespace, and File refers to the particular class. NOTEYou can view all the namespaces of the standard classes in the .NET Framework Class Library by viewing the Reference Documentation for the .NET Framework. Standard NamespacesThe classes contained in a select number of namespaces are available in your pages by default. (You must explicitly import other namespaces.) These default namespaces contain classes that you use most often in your applications:•System—Contains all the base data types and other useful classes such as those related to generating random numbers and working with dates and times. •System.Collections— Contains classes for working with standard collection types such as hash tables, and array lists.•System.Collections.Specialized— Contains classes that represent specialized collections such as linked lists and string collections.•System.Configuration— Contains classes for working with configuration files (Web.config files).•System.Text— Contains classes for encoding, decoding, and manipulating the contents of strings.•System.Text.RegularExpressions— Contains classes for performing regular expression match and replace operations.•System.Web— Contains the basic classes for working with the World Wide Web, including classes for representing browser requests and server responses. •System.Web.Caching—Contains classes used for caching the content of pages and classes for performing custom caching operations.•System.Web.Security— Contains classes for implementing authentication and authorization such as Forms and Passport authentication.•System.Web.SessionState— Contains classes for implementing session state. •System.Web.UI—Contains the basic classes used in building the user interface of pages.•System.Web.UI.HTMLControls— Contains the classes for the HTML controls. •System.Web.UI.WebControls— Contains the classes for the Web controls..NET Framework-Compatible LanguagesFor purposes of this book, you will write the application logic for your pages using Visual Basic as your programming language. It is the default language for pages (and the most popular programming language in the world). Although you stick to Visual Basic in this book, you also need to understand that you can create pages by using any language that supports the .NET Common Language Runtime. Out of the box, this includes C# (pronounced See Sharp), (the .NET version of JavaScript), and the Managed Extensions to C++.NOTEThe CD included with this book contains C# versions of all the code samples. Dozens of other languages created by companies other than Microsoft have been developed to work with the .NET framework. Some examples of these other languages include Python, SmallTalk, Eiffel, and COBOL. This means that you could, if you really wanted to, write pages using COBOL.Regardless of the language that you use to develop your pages, you need to understand that pages are compiled before they are executed. This means that pages can execute very quickly.The first time you request an page, the page is compiled into a .NET class, and the resulting class file is saved beneath a special directory on yourserver named Temporary Files. For each and every page, a corresponding class file appears in the Temporary Files directory. Whenever you request the same page in the future, the corresponding class file is executed.When an page is compiled, it is not compiled directly into machine code. Instead, it is compiled into an intermediate-level language called Microsoft Intermediate Language (MSIL). All .NET-compatible languages are compiled into this intermediate language.An page isn't compiled into native machine code until it is actually requested by a browser. At that point, the class file contained in the Temporary Files directory is compiled with the .NET framework Just in Time (JIT) compiler and executed.The magical aspect of this whole process is that it happens automatically in the background. All you have to do is create a text file with the source code for your page, and the .NET framework handles all the hard work of converting it into compiled code for you.ASP CLASSIC NOTEWhat about VBScript? Before , VBScript was the most popular language for developing Active Server Pages. does not support VBScript, and this is good news. Visual Basic is a superset of VBScript, which means that Visual Basic has all the functionality of VBScript and more. So, you have a richer set of functions and statements with Visual Basic.Furthermore, unlike VBScript, Visual Basic is a compiled language. This means that if you use Visual Basic to rewrite the same code that you wrote with VBScript, you can get better performance.If you have worked only with VBScript and not Visual Basic in the past, don't worry. Since VBScript is so closely related to Visual Basic, you'll find it easy to make the transition between the two languages.NOTEMicrosoft includes an interesting tool named the IL Disassembler (ILDASM) with the .NET framework. You can use this tool to view the disassembled code for any of the classes in the Temporary Files directory. It lists all the methods and properties of the class and enables you to view the intermediate-level code.This tool also works with all the controls discussed in this chapter. For example, you can use the IL Disassembler to view the intermediate-level code for the TextBox control (located in a file named System.Web.dll).About ModemTelephone lines were designed to carry the human voice, not electronic data from a computer. Modems were invented to convert digital computer signals into a form that allows them to travel over the phone lines. Those are the scratchy sounds you hear from a modem's speaker. A modem on the other end of the line can understand it and convert the sounds back into digital information that the computer can understand. By the way, the word modem stands for MOdulator/DEModulator.Buying and using a modem used to be relatively easy. Not too long ago, almost all modems transferred data at a rate of 2400 Bps (bits per second). Today, modems not only run faster, they are also loaded with features like error control and data compression. So, in addition to converting and interpreting signals, modems also act like traffic cops, monitoring and regulating the flow of information. That way, one computer doesn't send information until the receiving computer is ready for it. Each of these features, modulation, error control, and data compression, requires a separate kind of protocol and that's what some of those terms you see like V.32, V.32bis, V.42bis and MNP5 refer to.If your computer didn't come with an internal modem, consider buying an external one, because it is much easier to install and operate. For example, when your modem gets stuck (not an unusual occurrence), you need to turn it off and on to get it working properly. With an internal modem, that means restarting your computer--a waste of time. With an external modem it's as easy as flipping a switch.Here's a tip for you: in most areas, if you have Call Waiting, you can disable it by inserting *70 in front of the number you dial to connect to the Internet (or any online service). This will prevent an incoming call from accidentally kicking you off the line.This table illustrates the relative difference in data transmission speeds for different types of files. A modem's speed is measured in bits per second (bps). A 14.4 modem sends data at 14,400 bits per second. A 28.8 modem is twice as fast, sending and receiving data at a rate of 28,800 bits per second.Until nearly the end of 1995, the conventional wisdom was that 28.8 Kbps was about the fastest speed you could squeeze out of a regular copper telephone line. Today, you can buy 33.6 Kbps modems, and modems that are capable of 56 Kbps. The key question for you, is knowing what speed modems your Internet service provider (ISP) has. If your ISP has only 28.8 Kbps modems on its end of the line, you could have the fastest modem in the world, and only be able to connect at 28.8 Kbps. Before you invest in a 33.6 Kbps or a 56 Kbps modem, make sure your ISP supports them.Speed It UpThere are faster ways to transmit data by using an ISDN or leased line. In many parts of the U.S., phone companies are offering home ISDN at less than $30 a month. ISDN requires a so-called ISDN adapter instead of a modem, and a phone line with a special connection that allows it to send and receive digital signals. You have to arrange with your phone company to have this equipment installed. For more about ISDN, visit Dan Kegel's ISDN Page.An ISDN line has a data transfer rate of between 57,600 bits per second and 128,000 bits per second, which is at least double the rate of a 28.8 Kbps modem. Leased lines come in two configurations: T1 and T3. A T1 line offers a data transfer rate of 1.54 million bits per second. Unlike ISDN, a T-1 line is a dedicated connection, meaning that it is permanently connected to the Internet. This is useful for web servers or other computers that need to be connected to the Internet all the time. It is possible to lease only a portion of a T-1 line using one of two systems:fractional T-1 or Frame Relay. You can lease them in blocks ranging from 128 Kbps to 1.5 Mbps. The differences are not worth going into in detail, but fractional T-1 will be more expensive at the slower available speeds and Frame Relay will be slightly more expensive as you approach the full T-1 speed of 1.5 Mbps. A T-3 line is significantly faster, at 45 million bits per second. The backbone of the Internet consists of T-3 lines.Leased lines are very expensive and are generally only used by companies whose business is built around the Internet or need to transfer massive amounts of data. ISDN, on the other hand, is available in some cities for a very reasonable price. Not all phone companies offer residential ISDN service. Check with your local phone company for availability in your area.Cable ModemsA relatively new development is a device that provides high-speed Internet access via a cable TV network. With speeds of up to 36 Mbps, cable modems can download data in seconds that might take fifty times longer with a dial-up connection. Because it works with your TV cable, it doesn't tie up a telephone line. Best of all, it's always on, so there is no need to connect--no more busy signals! This service is now available in some cities in the United States and Europe.The download times in the table above are relative and are meant to give you a general idea of how long it would take to download different sized files at different connection speeds, under the best of circumstances. Many things can interfere with the speed of your file transfer. These can range from excessive line noise on your telephone line and the speed of the web server from which you are downloading files, to the number of other people who are simultaneously trying to access the same file or other files in the same directory.DSLDSL (Digital Subscriber Line) is another high-speed technology that is becoming increasingly popular. DSL lines are always connected to the Internet, so you don'tneed to dial-up. Typically, data can be transferred at rates up to 1.544 Mbps downstream and about 128 Kbps upstream over ordinary telephone lines. Since a DSL line carries both voice and data, you don't have to install another phone line. You can use your existing line to establish DSL service, provided service is available in your area and you are within the specified distance from the telephone company's central switching office.DSL service requires a special modem. Prices for equipment, DSL installation and monthly service can vary considerably, so check with your local phone company and Internet service provider. The good news is that prices are coming down as competition heats up.The NetWorksBirth of the NetThe Internet has had a relatively brief, but explosive history so far. It grew out of an experiment begun in the 1960's by the U.S. Department of Defense. The DoD wanted to create a computer network that would continue to function in the event of a disaster, such as a nuclear war. If part of the network were damaged or destroyed, the rest of the system still had to work. That network was ARPANET, which linked U.S. scientific and academic researchers. It was the forerunner of today's Internet.In 1985, the National Science Foundation (NSF) created NSFNET, a series of networks for research and education communication. Based on ARPANET protocols, the NSFNET created a national backbone service, provided free to any U.S. research and educational institution. At the same time, regional networks were created to link individual institutions with the national backbone service.NSFNET grew rapidly as people discovered its potential, and as new software applications were created to make access easier. Corporations such as Sprint and MCI began to build their own networks, which they linked to NSFNET. As commercial firms and other regional network providers have taken over the operation of the major Internet arteries, NSF has withdrawn from the backbone business.。