信息处理技术 Technology of Information Processing 潘晟旻 Instructor: Pan Shengmin 潘晟旻 Office : Computer Center. Kun Ming University of Science & Technology.

Ch10 信息处理技术 Networks

3 After this chapter, you should be able to: –Describe Internet communications and basic features –Demonstrate that you can use a search engine to locate information on the Web –Explain how an system works Chapter 10 Preview

4 – 描述互联网基本特性 – 利用搜索引擎定位、搜寻 WEB 中 有用信息 – 解释 系统如何工作 导读

Section A: Internet Basics 互联网基础

6 The Internet is a collection of networks that are linked together to exchange data and distribute processing tasks Communication between all of the different devices on the Internet is made possible by TCP/IP How does the Internet work?

Web Sites – various locations in cyberspace that correspond to a corporation, a store, a magazine, and more Search engines – help catalog a huge portion of the data stored on Web sites What kind of resources are available on the Internet?

– electronic messages –Mailing list server Blogs – refers to a personal journal 杂志 posted on the Web What kind of resources are available on the Internet?

Existing telephone line 现有的电话线 Cable television line 有线电视电缆 Personal satellite link 个人卫星连接 Wireless or cell phone service 无线或蜂窝 通信 / 手机 / 服务 High-speed telephone services –ISDN, DSL 高速连接服务 What are my options for Internet connections? / 可选择的连接方式 /

What are my options for Internet connections?

11 Dial-up connection – relatively simple and inexpensive Voiceband modem – converts digital signals into wave format to go over telephone lines and then at destination waves are converted back into digital Dial-up top speed is 56 Kbps What’s the easiest, cheapest way to access the Internet?

Requires 2 pieces of equipment –Network card – connects a personal computer to a local area network –Cable modem / 电缆调制解调器 /–changes computer’s signals into a form that can travel over cable TV links Does a cable modem provide a faster Internet connection?

/ 永不离线 /Referred to as an always-on connection / 永不离线 / Top speed is around 1.5 Mbps (25 times faster than dial-up) / 电话会议 /Suitable for most Internet activities, including real-time video and teleconferencing / 电话会议 / Does a cable modem provide a faster Internet connection?

Typically schools and business connect to a Local Area Network that is connected to the Internet These connections are frequently always- on connections What about access provided by a school or business network?

(Integrated Services Digital Network 综合服务 数字网 )ISDN (Integrated Services Digital Network 综合服务 数字网 ) – 64Kbps or 128 Kbps (Digital SubscriberLine 数字用户线 )DSL (Digital Subscriber [sQbs5kraibE] Line 数字用户线 ) –125 times faster than 56 Kbps / 接近 / –Comes from phone company, requires proximity / 接近 / to a switching station DSS (Digital Satellite Service) – 500 Kbps What other high-speed Internet access options are available?

A company that provides Internet access to businesses, organizations, and individuals –An ISP ( 网络服务提供商 )that offers dial-up connections, for example, maintains a bank of modems –AOL ( 美国在线服务公司, )Earthlink Internet Service Providers What’s an ISP?

地域覆盖Geographical coverage 地域覆盖 服务类型Type of service 服务类型 QoS 服务质量Quality of service QoS 服务质量 月服务费Cost of monthly service 月服务费 Cost of equipment and installation 设备及安装费 设备及安装费 附加服务Extra services 附加服务 客户服务Customer service 客户服务 How do I choose an ISP? 选择运营商的原则

A user ID becomes a person’s unique identifier A password is a different series of characters that verifies your identity 大小 写敏感Some computers are case-sensitive; ( 大小 写敏感 ) they differentiate between upper and lower case letters User ID’s and Passwords

How do I choose a secure password?

Section B: Web Basics Web 基础

The Web is a collection of files that can be linked and accessed using HTTP WEB 就是利用超文本传输协议, 彼此互联的, 可 被访问的文件的集合. HTTP (Hypertext Transfer Protocol 超文本传输 协议 ) - the protocol that allows Web browsers to communicate with Web servers HTTP: 是允许 WEB 浏览器和 WEB 服务器彼此 进行通信联系的协议. 万 维 网 The World Wide Web 万 维 网

22 Many of these files produce documents called Web pages 具有如上特征的文件被称为 ” 网页 ” Web site - location on a computer somewhere on the Internet that stores a collection of Web pages – 存储网页集合的, 位于 Internet 上的计算机 称为 WEB 站点. 万 维 网 The World Wide Web 万 维 网

Web server (Web 服务器 ) - computer with special software for transmitting Web pages over the Internet Home page ( 主页 - 烘培鸡 ^_^)- identifies the site and contains links to other pages at the site Web sites are composed of a series of Web pages What is the Web?

URL (Uniform Resource Locator) - an Internet address of a document on a computer –Begins with What is the Web? 协议标准WEB服务器名称 文件夹名 文件名及扩展名

Web browsers are software programs that run on your computer and help you access Web pages 浏览器是计算机中帮助我们访问网页的软 件, 主要有 : –Internet Explorer –Netscape What is a browser?

Web site that provides a variety of tools to help you find information –Helps you locate web pages on certain topics –Enter keywords or descriptions –AltaVista( 阿塔维斯塔 ), Google, Yahoo, etc. 什么是搜索引擎 What is a search engine? 什么是搜索引擎

Describes information you want to find You can enter more than one keyword 可以键入一个或多个关键词 A search operator describes a relationship between keywords –AND, OR, and NOT –Quotation marks 引号 –NEAR –Wildcards [ 计 ] 通配符 –Field / 领域 / Searches Exactly what is a query? 查询确切的定义是什么 ?

Section C: Basics电子邮件基础

/ 帐号 /Any person with an account / 帐号 / / 存储区 /”/ 邮箱 /An account provides the rights to a storage area / 存储区 / or “mailbox ”/ 邮箱 / / 唯一的 /Each mailbox has a unique / 唯一的 / address Who can use ?

A document that is composed on a computer and remains in digital form so that it can be transmitted to another computer Every message includes: 信息头部 –A message header 信息头部 信息体 –The body of the message 信息体 邮件信息的确切定义是什么 ? Exactly what is an message? 邮件信息的确切定义是什么 ?

What can I do with basic ?

After you receive a message, you can pass it on to other people The original message is copied and then you can enter the address of the person to receive the message, and even add a note about why you are passing it along( 转发邮 件 ) How does forwarding work?

/ 接收者 /File that travels with a message to the recipient / 接收者 / MIME provides a way of disguising the file as plain ASCII text that can travel over the Internet MIME:Multipurpose Internet Mail Extension protocol 多用途的网际邮件扩 充协议 什么是邮件的附件 ? What’s an attachment? 什么是邮件的附件 ?

34 Netiquette is online jargon [5dVB:^En]( 行 话 ) for “Internet etiquette 网络礼节 Notify 通告 recipients of viruses Stay alert for viruses Explain all attachmentsDon’t send huge attachments Don’t send replies to “all recipients ” Use the Bcc function for group mailings Use smileys cautiously : - ) Be cautious with sarcasm 讽刺 and humor Be concise 简明 Be polite Be careful what you send Check spelling Use uppercase and lowercase letters Put a meaningful title on the subject line Is different than other types of communication?

–POP Post Office Protocol 邮局协 议 –IMAP Internet Message Access Protocol, Internet 消息访问协议 –Web-based 基于 WEB 的电 子邮件 Technology: What is an system?

How do I use Web-based ?

/ 提供 /Your ISP will offer / 提供 / POP or IMAP POP server – a computer that stores your incoming messages until they can be transferred to your hard disk Using POP requires client software 电子邮件客户端软件 Outgoing mail is routed by an SMTP server How do POP and IMAP work?

How do POP and SMTP work?

Requires client software Transfers to your computer Consider the following when deciding: –Control 控制 –Security 保密 –Travel 传输 Is POP mail better than Web-based ?

Conclusion You should now be able to: –Describe Internet communications and basic features –Explain how an system works

41 全章总结 你现在应该具备如下能力 : – 描述互联网通信技术及其基本特征 – 解释电子邮件系统是如何工作的.