Unit 8 Computer Networking
Text 1 Data Communications
Exercises
1. Fill in the blanks with appropriate words according to the text.
(1) The end equipment is either __generates the digital information for transmission_ or_ uses the received digital data. (2) When digital data are transmitted, they are _in serial form_. (3) _DTE___ is data terminal equipment.
(4) _STACO is the corresponding unit at the secondaries.
(5) Between the DTEs, first is _the modems_, and then is the communications equipment__.
(6) _DCE__ accepts the serial data stream from the DTE.
(7) At the transmit end, the modem can be considered a form of _digital-to-analog_ converter, while at the receive end, it can be considered a form of analog-to-digital__ converter.
(8) DCE converts the received_ analog signal_ to a serial digital data stream_. 2. Multiple choices.
(1) The end equipment in a communication system includes _ABCD_. A. computers B. CRTs
C. printers D. keyboards
(2) The equipment B_D__.
A. manipulates digital information internally in serial form B. manipulates digital information internally in word units C. transfers the number of bits in parallel D. transfers the number of bits in serial form (3) DTE is __BD_.
A. Digital T-carrier B. data terminal equipment C. satellite
D. the last piece of equipment that belonged to the subscriber in a data link system (4) There are AB_ between the DTEs. A. the modem
B. communications equipment C. digital-to-analog converter
D. will be replaced by an updated standard
3. Translate and analyze the following sentences.
(5) This equipment generally operates digital information internally in word units.
句子组成：in word units介词短语作方式状语修饰operates 翻译：_这种设备通常在内部以字为单位处理数字信息_____ (6) It converts the received analog signal to a serial digital data stream. 句子组成：convert……to指将……转换成…… 翻译： 它把接收到的模拟信号转换成串行数字数据流
(7) Data communications equipment (DCE) accepts the serial data stream from the DTE.
句子组成：from the DTE修饰动词accept 翻译：数据通信设备（DCE）从DTE接收串行数据流 Reading comprehension.
Security is an important consideration in the Internet world. The computer has a way of knowing who you are. Most LANs or mainframes require each user to log in, or sign on to the system. To do this, you should type in your user ID before a prompt. You are then prompted for a password. Passwords are special codes you use to “lock” your account. Obviously you need to be careful about protecting your password if you are building nuclear power plants or something, but what about the rest of us? A student recently got some help from her friend on email. She gave him her password to a class account, and he wrote it down. Apparently some of his buddies found the password and logged in using the student’s user ID and password, and sent a very obscene message to the class. The student nearly lost her account, because she had been sloppy with her password.
Change you password regularly!
Some hints:
? Don’t use your dog’s name. People will guess it.
? Don’t use words in English, people can hook up spell checkers. ? Consider combining words and numbers.
Answer the following questions according to the article above.
(8) What does the passage mainly discuss?
Security is an important consideration in the Internet world.
(9) According to the passage, we know security is an important consideration __in the
Internet world_. (10) Why the author thinks that is important to protect your password if you are building
nuclear power plant or something? Because the password may be used by other people (11) At last, the author give some hints, what are they?
They are: first, don’t use your dog’s name. People will guess it. Second, don’t use words in English, people can hook up spell checkers. And last, consider combining words and numbers.
Text 2 Architecture of Computer Networks
Exercises
1. Fill in the blanks with appropriate words according to the text.
(12) Computer network is a complex unit, it consists oftwo or more connected
computing units. (13) Design of a network and its logical structure should comply with a set of design
principles. (14) Two important network architectures are: the OSI reference model and the TCP/IP reference model. (15) The _OSI__ model was created by the ISO. (16) Note that the OSI model itself is not a network architecture__.
(17) TCP/IP is a communication protocol, it provides many different networking services.
(18) The TCP/IP Internet protocol suite is formed from two standards :_the TCP__ and the IP__. (19) __TCP/IP__ is the foundation of the Internet as we know it today.
(20) TCP means it is on the __transport__ layer and IP means it is on the __network__ layer separately. 2. Decide whether the following statements are True or False.
(21) Design of a network and its logical structure should comply with a set of design
principles. ( √ ) (22) The OSI model was not created by the ISO. ( × ) (23) The network architecture is a layer-based. ( √ ) (24) The OSI model is a foundation for all comparing protocols. ( × ) (25) The OSI model is a network architecture. ( × ) (26) The TCP/IP Internet protocol suite is formed from three standards. ( × ) (27) TCP means it is on the network layer and IP means it is on the transport layer
separately. ( × ) 3. Translate and analyze the following sentences.
(28) It is used for the purpose of data communication and resource sharing. 句子组成：it 代指计算机网络，for引导的短语结构修饰used 翻译：_它用于数据通信和资源共享。__________________
(29) They include: the organization of functions, the description of data formats and
procedure.
句子组成：include引导三个并列结构
翻译：其中包括：功能的组织以及数据格式和过程的说明。 (30) However, ISO has also produced standards for all the layers.
句子组成：_however表语气的转折，for all the layers作目的状语_ 翻译：_然而，ISO还是对各层制定了标准__
(31) These protocols are continually changing and evolving to support the needs of the user community. 句子组成：change与evolve为两个并列动词，of the user community作后置定语修饰need 翻译：__这些协议在用户们的支持下不断地改变和进化着。
(32) TCP/IP is a communication protocol, it provides many different networking
services.
计算机专业英语Unit 8
