You’ll notice that this computer features a 60-MHz Pentium CPU， 8 MB of RAM memory， and a 540 megabyte （MB） hard drive， among other things. But how good a system is this？ Are these features important to the user？ Is this the right combination of features that you need in your computer to have the computer perform the work that you wish to get done？ Is a 60-MHz Pentium the best choice of a CPU？ Perhaps we are paying too much for the performance that we need. Or maybe we need more.
What does the presence of a 64-bit PCI video accelerator imply in the context of a long-term investment of computers for your organization？ What other information about this system would allow you to make a more informed decision？
Some of the expressions used in these articles and ads are obvious from the context. Other references may be more obscure. Presumably， everyone today knows what a “monitor” is. But how many people know what the terms “cache memory” or “multitasking” or “PCI bus” mean or what their importance is？ Yet all these expressions have appeared recently in daily newspaper advertisements with the assumption that people would understand the meaning of the ad.
Perhaps you are a student studying to become a computer professional， or perhaps you are simply a user wanting a deeper understanding of what the computer is all about. In either case， you will probably be interacting with computers for the rest of your life. It's nice （as well as useful） to know something about the tools of the trade. More important， understanding the computer system's operations has an immediate benefit： it will allow you to use the machine more effectively.
【New Words】
optimum
最佳的，最优的
accelerator
加速器，加速者
jargon
行话，术语
presumable
冒昧的，不客气地
cache memory
高速缓冲存储器
PCI（Peripheral Control Interface）
外围控制接口
3.2 Function of Operating Systems
All application programs share some tasks in common. They include accepting characters typed at the keyboard， displaying information on the screen， managing information on a disk， and managing information in memory. The operating system takes care of the details of these tasks. A most important example of how operating systems support application programs is the task of managing files. A file is a named collection of information. Whether your application is general or special purpose， your program needs to store information in files.
The operating system takes care of：
Formatting the disk， which involves electronically preparing the disk to be able to store files.
Managing the location of information on the disk.
Checking to make sure that errors do not occur when reading to and writing from the disk.t
Performing the input and output necessary to retrieve and store information on the disk.
Errors may occur in the CPU and memory hardware （such as a memory error or a power failure）， in I/0 devices （such as a parity error on tape， a card jam in the card reader， or the printer out of paper）， or in the user program （such as an arithmetic overflow， an attempt to access illegal memory location， or using too much CPU time）. For each type of error， the operating system should take the appropriate action to assure correct and consistent computing.
Operating systems also manage the other components of a computer system. They support programs， called device drivers， which control various hardware devices， such as the keyboard， display screen and printer. The device driver translates instructions from the print application program wants to print something， it simply sends the information and the appropriate instructions to the operating system， which， in turn， calls upon the printer device driver to manipulate the printer to perform the desired task.
【Vocabulary】
share
vt. 分配，分享 n. 共享，份额
task
n. 任务，作业 vt. 分配任务
general
adj. 一般的，普通的
format
n. 形式，格式 vt. 格式化
location
n. 位置，场所，特定区域
retrieve
vt. 找到，重新找回
store
vt. 存储，储备 n. 商店
jam
n. 果酱，困境 vt. 拥挤，堵塞
component
n. 成分 adj. 组成的，构成的
manipulate
vt. 操作，操纵，利用
desired
adj. 渴望的，想得到的
takes care of
照顾，处理
【参考译文】
操作系统的功能
所有的应用程序都共享一些任务。包括它们在键盘上输入的字符，在屏幕上显示信息，管理磁盘和内存信息，靠操作系统来处理这些任务的细节。文件管理是操作系统如何支持应用程序的一个重要例子。文件是信息的集合。无论应用程序是通用的还是专用的，都需要以文件的形式存储信息。
操作系统有以下功能：
格式化磁盘，将磁盘电子化，从而能存储文件。格
管理磁盘中信息存放的位置。管
当从磁盘中读写数据时检查是否有错误。当
完成对磁盘进行检索和存储信息时必要的输入输出工作。完
错误可能发生在CPU和内存中（例如一个内存错误或电源故障），也可能发生在I/O设备中（例如磁带中的一个奇偶错误，磁带读取器读卡堵塞，或打印机卡纸等），或者发生在用户程序中（例如一个计算溢出，访问非法内存空间，或使用太多的CPU时间等）。对任何一种类型的错误，操作系统应当采取合适的措施来保证正确和没有矛盾的运算。
操作系统也管理计算机系统中的其他组件。它们控制设备驱动程序来控制不同的硬件设备，例如键盘、显示器和打印机。这些设备驱动程序解释打印应用程序中的指令，它简单地向操作系统发送信息和可用的指令，有顺序地调用打印驱动程序来处理打印机中将要执行的其他任务。
【Reading Material】
The Computer’s Traffic Cop
Imagine the traffic in a downtown New York City intersection at rush hour， and you’ll have a good idea of what it’s like inside a computer. Electrons are whizzing around at incredible speeds transported this way and that by the electronic equivalent of a hurried traffic cop. Impatient peripherals and programs are honking electronic “horns”， trying to get the cop’s attention. As if the scene weren’t chaotic enough， the “mayor” （the user） wants to come through right now. Somehow， everyone gets though.
The computer’s operating system （OS） keeps traffic running smoothly. You can think of the operating system as a computerized version of a traffic cop， standing at the intersection of the computer’s hardware， application programs， and the user.
Because operating system work closely with the computer’s hardware and with application programs， all of these components must be designed to work together harmoniously. The operating system requires a specific type or family of processors. For example， Microsoft Windows 98 requires Intel Processors， such as the Pentium. Similarly， application programs must be designed to work with a specific operating system. A Macintosh program requires Mac OS and will not run on Microsoft Windows.
