计算机专业英语的课文与翻译

Unit 8 Computer Networking

Text 1 Data Communications

The end equipment can be computers, printers, keyboards, CRTs, and so on.

They are either

generates the digital information for transmission or uses the received digital data. This equipment

generally operates digital information internally in word units.

DTE is data terminal equipment. A station controller (STACO)

is the corresponding unit at

the

secondaries.

At

one

time,

the

DTE

was

the

last

piece

of

equipment

that

belonged

to

the

subscriber

in

a

data

link

system.

Between

the

DTEs,

first

is

the

modem,

and

then

is

the

communications

equipment.

The

communication

equipment

is

owned

and

maintained

by

Telco.

Data communications equipment (DCE) accepts the serial data stream from the DTE. And DCE

converts it to some form of analog signal suitable for transmission on voice-grade lines. At the

receive

end,

the DCE performs

the

reverse

function.

It

converts

the

received

analog

signal

to

a

serial digital data stream. The simplest form of DCE is a modem (modulator/demodulator) or data

set. 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.

参考译文

数据通信

终端设备可以是计算机、打 印机、键盘、

CRT

等。它们可以生成要发送的数字信息，

也可以使用所接收的数字数据。这种设备通常在内部以字为单位处理数字信息。

DTE

一般称为数据终端设备。

< br>辅助设备一方的相应设备是工作站控制器

（

STACO< /p>

）

。

同时，

DT E

也是数据链路系统中属于用户端的最后一个设备。在两个

DT E

之间，先是调制解调器，

接着是属于

Telco

电话公司维护的通信设备。数据通信设备（

DCE< /p>

）从

DTE

接收串行数据流，

在接收端，< /p>

DCE

完成相反的功能，

把接收到的模拟 信号转换成串行数字数据流。

最简单的

DCE

< br>是调制解调器或数据传送机。

在发

送端，调制解调器可以 视为一种数

/

模转换器，而在接收端则可视为一种模／数转换器 。

Text 2 Architecture of Computer Networks

Computer network is a complex unit, it consists of two or more connected computing units. It

is used for the purpose of data communication and resource sharing. Design of a network and its

logical structure should comply with a set of design principles. They include: the organization of

functions, the description of data formats and procedure.

In the following two sections we will discuss two important network architectures, the OSI

reference model and the TCP/IP reference model.

(1)

the OSI reference model

The

OSI

(open

systems

interconnection)

model

was

created

by

the

ISO.

This

model

is

a

foundation for comparing protocols; However, more protocols deviate from the rules set up by the

OSI model.

The OSI model has seven layers. Note that the OSI model itself is not a network architecture.

It just tells what each layer should do. However, ISO has also produced standards for all the layers.

Each one has been published as a separate international standard.

(2)

the TCP/IP reference model

TCP/IP is a communication protocol; it provides many different networking services.

The

TCP/IP

Internet

protocol

suite

is

formed

from

two

standards:

the

TCP

(Transmission

Control Protocol) and the IP (Internet Protocol). TCP means it is on the transport layer. IP means it

is on the network layer. On top of the transport layer is the application layer. It contains all the

higher-level

protocols.

The

early

ones

included

virtual

terminal

(TELNET),

file

transfer

(FTP),

electronic mail (SMTP)

and domain name service (DNS).

As

we

know,

TCP/IP

is

the

foundation

of

the

Internet.

These

protocols

are

continually

changing and evolving to support the needs of the user community.

参考译文

计算机网络结构

计算机网络是由两个 或多个计算机设备互连而成的一种复合系统，

它用于数据通信和资

源共享。

网络设计及其逻辑结构应该遵循一套设计原则，

其中 包括：

功能的组织以及数据格

式和过程的说明。

在下面的两小节里，我们将讨论两个重要的网络体系结构，即

OSI

参考模型和

TCP/IP

参考模型。

(1)

OSI

参考模型

OSI

模型（开放系统互联参考模型）是由国际标准化组织（

ISO

）开发的一个建议。相

对于其他协议来说，此种模式为 基础模式。然而，更多的协议是背离

OSI

模型的。