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1、计算机专业英语,6-1,Computer English,Chapter 6 Software Engineering,计算机专业英语,6-2,掌握软件的生命周期的基本术语与知识； 了解软件工程的发展趋势； 了解软件设计方法； 了解软件安全的有关知识； 掌握复杂定语(从句)的翻译技巧。,Requirements:,计算机专业英语,6-3,New Words n.近似,途径 conducive adj.有助于.的 evasive adj.逃避的；回避的；推托的framework n.构架, 框架, 结构,计算机专业英语,6-4,New Words 统一体 modular design 标准设计,
2、 模块化设计object-oriented 面向对象的 stub n.树桩, 桩模块give way to 让路,让步 trial-and-error n.试错，反复试验malfunction n.故障，出错 waterfall model 瀑布模型analogy n.类似, 类推 after all adv.毕竟stark adv.完全地 trial-and-creative 试验并创造的nonstructure 非结构性 intuition n.直觉, 直觉的知识contradiction n.反驳, 矛盾 incremental model 增量式模型update v.修正, 更新；n.
3、更新 stepwise adj.楼梯式的, 逐步的prototype n.原型 evolutionary prototyping 演化式原型in favor of adv.赞同, 有利于 throwaway prototyping 抛弃原型iron out 消除；解决困难等 documentation n.文件debugging n.调试 spreadsheet n.电子制表软件, 电子数据表 Abbreviations CASE (computer-aided software engineering) 计算机辅助软件工程 GUI (Graphical User Interfaces) 图形
4、用户界面,计算机专业英语,6-5,6.1 The Software Life Cycle,6.1.1 The Cycle as a Whole,Figure 6-1 The software life cycle,The most fundamental concept in software engineering is the software life cycle.,软件生命周期是软件工程中最基本的概念。,计算机专业英语,6-6,6.1.1 The Cycle as a Whole,The software life cycle is shown in Figure 6-1. This
5、figure represents the fact that once software is developed, it enters a cycle of being used and modified that continues for the rest of the softwares life. Such a pattern is common for many manufactured products as well. The difference is that, in the case of other products, the modification phase i
6、s more accurately called a repair or maintenance phase because other products tend to move from being used to being modified as their parts become worn.,在图6-1中展示了软件的生命周期。这个图说明了一个事实：一旦软件开发完成，它就进入了使用和修改的循环，并且这个循环将在软件生命期的剩余时间中不断进行。这样的模式对机器制造的产品而言也是很普通的。不同之处在于，对于其他产品，软件工程中的修改阶段要被更精确地称作修理或者维护阶段，因为其他产品由于部
7、件的磨损会有从使用到修改的过程。,计算机专业英语,6-7,6.1.1 The Cycle as a Whole,Software, on the other hand, does not wear out. Instead, software moves into the modification phase because errors are discovered, because changes in the softwares application occur that require corresponding changes in the software, or because
8、 changes made during a previous modification are found to induce problems elsewhere in the software. For example, changes in tax laws may require modifications to payroll programs that calculate withholding taxes, and all too often these changes may have adverse effects in other areas of the program
9、 that may not be discovered until some time later.,当然，软件不存在磨损的问题。但是，软件进入修改阶段或者是因为错误被发现，或者是因为要在软件的应用程序中进行修改从而修改了软件，或者是因为先前的改变又引起了软件其他地方出现了新的问题。例如，税务法案的改变导致对计算扣税的工资程序进行修改，而太频繁的修改则会在软件的其他地方引起反面的作用，而这些是不会被立即发现的。,计算机专业英语,6-8,6.1.1 The Cycle as a Whole,Regardless of why software enters the modification ph
10、ase, the process requires that a person (often not the original author) study the underlying program and its documentation until the program, or at least the pertinent part of the program, is understood. Otherwise, any modification could introduce more problems than it solves. Acquiring this underst
11、anding can be a difficult task even when the software is well-designed and documented. In fact, it is often within this phase that a piece of software is finally discarded under the pretense (too often true) that it is easier to develop a new system from scratch than to modify the existing package s
12、uccessfully,不管因为什么原因软件进入了修改阶段，这个过程需要人们（通常不是原始的作者）研究程序及其文档，直到程序或者至少是相关部分的程序能够被理解。否则，任何的修改将导致比它所解决问题还要更多的问题出现。即使软件有优秀的设计和齐备的文档，理解也是一个很困难的工作。事实上，常常是在这个阶段，一个有用的软件片段最终就被放弃了（常常是这样），而开发一个新的系统比成功地修改现有软件更容易。,计算机专业英语,6-9,6.1.1 The Cycle as a Whole,Experience has shown that a little effort during the developme
13、nt of software can make a tremendous difference when modifications in the software are required. 经验告诉我们,软件开发过程中的一丁点付出，会在软件需要修改的时候带来巨大的不同。,In turn, most of the research in software engineering focuses on the development stage of the software life cycle, with the goal being to take advantage of this e
14、ffort-versus-benefit leverage. 反过来，大多数软件工程的研究都集中于软件生命周期的开发阶段，它们的目标是要利用这个付出与收益的杠杆作用。,计算机专业英语,6-10,6.1.1 The Cycle as a Whole,The Traditional Development Phase The stages within the development phase of the software life cycle are analysis, design, implementation, and testing (Figure 6-2).,软件生命周期的开发阶段
15、包括分析、设计、实现与测试等步骤（如图6-2所示）。,计算机专业英语,6-11,6.1.1 The Cycle as a Whole,The Traditional Development Phase Analysis The development phase of the software life cycle begins with analysis-a major goal being to identify the needs of the user of the proposed system. If the system is to be a generic product so
16、ld in a competitive market, this analysis would involve a broad-based investigation to identify the needs of potential customers. If, however, the system is to be designed for a specific user, then the process would be a more narrow investigation.,分析 软件生命周期的开发阶段以分析开始主要目标是确定用户对所提出系统的需求。如果系统是一个在竞争的市场上销售的通用产品，这个分析将会包括一个广泛的调查来发现潜在用户的需要。但是，如果系统是为特殊用户设计的，那么这个过程就是一个更专业的调查。,计算机专业英语,6-12,6.1.1 The Cycle as a Whole,The Traditional Development Phase As the needs of the potential user ar
