《计算机科学概论（英文版·第5版）》书评-杂志之家

内容简介

《计算机科学概论(英文版第5版)》由当今该领域备受赞誉且经验丰富的教育家戴尔和刘易斯共同编写，介绍计算机科学领域的基础知识，为广大学生勾勒了一幅生动的画卷。就整体而言，全书内容翔实、覆盖面广，旨在向读者展示计算机科学的全貌；从细节上看，本书层次清晰、描述生动，基于计算机系统的洋葱式结构，分别介绍信息层、硬件层、程序设计层、操作系统层、应用程序层和通信层，涉及计算机科学的各个层面。

本书贯穿了计算机系统的各个方面，非常适合作为计算机专业的计算机导论课程教材。为后续专业课程打下坚实的基础；同时还适合作为非计算机专业的计算机总论课程教材，提供计算机系统完整的介绍。

作者简介

Nell Dale计算机科学领域广受推崇的教育家。在得克萨斯大学奥斯汀分校执教的25年中，她编写了20多本计算机科学方面的本科生教材。由于对计算机科学教学领域的突出贡献，1996年她获得TACM SIGCSE计算机科学教育最杰出贡献奖。

John Lewis计算机科学领域著名的教育家和作家，目前为维拉诺瓦大学计算机科学系副教授。他编写的Java软件及程序设计教材在该类书籍的排行榜上位居前列。他获得了很多教学方面的奖，包括大学教学奖和杰出教学Goff奖。他的研究兴趣包括面向对象技术、多媒体以及软件工程。

在线预览

Numbers are crucial to computing.In addition to using a computer to execute numeric computations, all types of information that we store and manage using a computer are ultimately stored as numbers.At the lowest level, computers store all information using just the digits 0 and 1.So to begin our exploration of computers, we need to first begin by exploring numbers.

First, let's recall that numbers can be classified into all sorts of categories.There are natural numbers, negative numbers, rational numbers, irrational numbers, and many others that are important in mathematics but not to the understanding of computing.Let's review the relevant category definitions briefly.

First, let's define the general concept of a number: A number is a unit belonging to an abstract mathematical system and is subject to specified laws of succession, addition, and multip}ication.That is, a number is a representation of a value, and certain arithmetic operations can be consistently applied to such values.

Now let's separate numbers into categories.A natural number is the number 0 or any number obtained by repeatedly adding 1 to this number Natural numbers are the ones we use in counting.A negative number is less than zero and is opposite in sign to a positive number.An integer is any of the natural numbers or any of the negatives of these numbers.A rational number is an integer or the quotient of two integers-that is, any value that can be expressed as a fraction.

In this chapter, we focus on natural numbers and the ways that they are represented in various number systems.As part of our discussion, we establish how all number systems relate to each other.In Chapter 3, we examine the computer representation of negative and rational numbers, as well as how we use numbers to represent other forms of data such as characters and images.

Some of the material in this chapter may already be familiar to you.Certainly some of the underlying ideas should be.You probably take for granted some basic principles of numbers and arithmetic because you've become so used to them.Part of our goal in this chapter is to remind yo, of those underlying principles and to show you that they apply to all number systems.Then the idea that a computer uses binary values-that is, ls and 0s-to represent information should be less mysterious.

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