Analog computers are analog devices.That is,they have continuous states rather than discrete numbered states.An analog computer can represent fractional or irrational values exactly, with no round-off.Analog computers are almost never used outside of experimental settings.模拟计算机是模拟设备。
也就是说，他们是连续状态而不是离散的有限状态。
一个模拟计算机可以精确代表小数或无理数，没有舍入。
模拟计算机几乎从不被使用在实验设置以外。
A processor typically contains an arithmetic/logic unit(ALU),control unit(including processor flags,flag register,or status register),internal buses,and sometimes special function units(the most common special function unit being a floating point unit for floating point arithmetic).一个处理器通常包含一个算术/逻辑单元（运算器），控制单元(包括处理器标志，标志寄存器，或状态寄存器)，内部总线，有时特殊功能单元(最常见的特殊功能单元作为一个浮点单元用于浮点运算)。
CISC stands for Complex Instruction Set Computer.Mainframe computers and minicomputers were CISC processors,with manufacturers competing to offer the most useful instruction sets.Many of the first two generations of microprocessors were also CISC.CISC代表复杂指令集计算机。
大型计算机和小型计算机是CISC处理器，与制造商竞争提供最有用的指令集。
微处理器的前两代中许多也是CISC。
Lesson2Supercomputer is a broad term for one of the fastest computers currently available. Supercomputers are very expensive and are employed for specialized applications that require immense mounts of mathematical calculations(number crunching).超级计算机是一个广泛的术语，因为它是目前可用的最快的计算机之一。
超级计算机是非常昂贵的，并且它被用于需要大量的数学计算（数字运算）的专门应用。
It is a midsize computer.In the past decade,the distinction between large minicomputers and small mainframes has blurred,however,as has the distinction between small minicomputers and workstation.But in general,a minicomputer is a multiprocessing system capable of supporting up to200users simultaneously.它是一个中型计算机。
在过去的十年中，大的小型机和小的大型机之间的区别已经模糊，然而，有小的小型机和工作站之间的区别。
但在一般情况下，一个小型机是一个能够同时支持多达200个用户的多处理系统。
Workstations generally come with a large,high-resolution graphics screen,a large amount of RAM,built-in network support,and a graphical user interface.Most workstations also have a mass storage device such as disk drive,but a special type of workstation,called a diskless workstation,comes without a disk drive.工作站一般都配有一个大的，高分辨率的图形屏幕，大量的内存，内置网络支持以及一个图形用户界面。
大多数工作站也有一个大容量存储设备如磁盘驱动器，但是一种特殊类型的工作站，被称为无盘工作站，是不带磁盘驱动器的。
Most desktop displays use liquid crystal display(LCD)or cathode ray tube(CRT)technology, while nearly all portable computing devices such as laptops incorporate LCD technology.大多数桌面显示使用液晶显示器(LCD)或阴极射线管(CRT)技术，而几乎所有便携式计算设备如笔记本电脑包含LCD技术。
For widescreen LCD monitors,the aspect ratio is16:9(or sometimes16:10or 15:9).Widescreen LCD displays are useful for viewing DVD movies in widescreen format, playing games and displaying multiple widows side by side.High definition television (HDTV)also uses a widescreen aspect ratio.对于宽屏液晶显示器来说，屏幕高宽比是16:9，(或有时为16:10或15:9)。
宽屏液晶显示器对于用宽屏格式观看DVD电影，玩游戏和并排显示多个窗口是有用的。
高清晰度电视(HDTV)也使用一个宽屏高宽比。
For LCD monitors,screen size is measured diagonally from the inside of the bevel edge.The measurement does not include the casing as indicated in the image below.对于液晶显示器来说，屏幕尺寸是从斜面边缘的内侧对角测量的。
而测量不包括下面的图像显示的外壳。
Lesson4Single-user,single task—As the name implies,this operating system is designed to manage the computer so that one user can effectively do one thing at a time.The Palm OS for Palm handheld computer is a good example of a modern single-user,single-task operating system..单用户，单任务。
顾名思义，这个操作系统被设计来管理计算机，以便一个用户可以有效地在一个时间做一件事。
用于掌上电脑的Palm OS是一个现代化的单用户单任务操作系统的一个很好的例子。
Single-user,multi-tasking—This is the type of operating system most people use on their desktop and laptop computers today.Microsoft’s Windows and Apple’s MacOS platforms are both examples of operating systems that will let a single user have several programs in operating at the same time.单用户，多任务。
这是如今大多数人在他们的台式机和笔记本电脑上使用的操作系统类型。
微软的Windows和苹果的MacOS的平台是两个可以让一个单用户在同时操作几个节目的操作系统的例子。
Multi-user—A multi-user operating system allows many different users to take advantage of the computer’s resources simultaneously.The operating system must make sure that the requirements of the various users are balanced,and that each of the programs they are using has sufficient and separate resources so that a problem with one user doesn’t affect the entire community of users.多用户。
一个多用户操作系统允许许多不同的用户同时利用计算机的资源。
操作系统必须确保各用户的需求是平衡的，并且他们正在使用的每个程序具有充分和独立的资源，以便一个用户的一个问题不会影响用户的整个社区。
Agile software development processes are built on the foundation of iterative development. To that foundation they add a lighter more people-centric viewpoint than traditional approaches.Agile processes use feedback,rather than planning,as their primary control mechanism.敏捷软件开发过程是建立在迭代开发的基础上的。