问题 单项选择题

在CORBA体系结构中,负责屏蔽底层网络通信细节的协议是 (53)

A.IDL

B.RPC

C.ORB

D.GIOP

答案

参考答案:C

解析: 我们只解释几个名词。
ORB (Object Request Broker,对象请求代理)作为一个“软件总线”来连接网络上的不同对象,提供对象的定位和方法调用,它是CORBA实现的关键。
GIOP (General Inter-ORB Protocol,通用ORB之间的协议)定义了一个不同ORB之间的接口。GIOP是CORBA方法调用的核心部分。GIOP不基于任何特别的网络协议,如IPX或TCP/IP。为了确保互操作性,OMG必须将GIOP定义在所有供应商都支持的特定传输之上。如果有详细和简洁的消息规范,则不会提供互操作性,因为所有供应商都使用不同的传送机制来实现这个互操作性。
IDL (Interface Definition Language,接口定义语言)定义客户和服务器之间的静态接口,通过编译器生成客户存根、服务器框架,以及根据支持的语言映射,自动生成来自一个CORBA IDL的代码。目前支持的语言映射包括:Java、C++、Ada、SmallTalk和Cobol等。CORBA IDL是由对象管理组织(Object Management Group)为定义所有的CORBA界面而制定的。
RPC(远程过程调用)是一种协议,程序可使用这种协议向网络中的另一台计算机上的程序请求服务。由于使用RPC的程序不必了解支持通信的网络协议的情况,因此RFC提高了程序的互操作性。在RPC中,发出请求的程序是客户程序,而提供服务的程序是服务器。

单项选择题
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                                                    Ani-mazing Animation Contest

     Ani-mazing is proud to announce its second animation (动画片) contest to introduce new animation

talents to the world.Contest entries (参赛作品) will be shown at the West Coast Animation Exhibition

from September 20.The exhibition will last for a week.Winners will be determined by a group of

Animation Industry experts who will review every entry.The result will be announced on September 28,

2011, when the awards ceremony will be held at the world - famous Egyptian Theatre, in Hollywood.We

are also planning to have a number of programs leading up to September 28, so hopefully this second year

will be a" Week of Animated Shorts".

     Cash prizes ranging from $500 to $5,000 will be awarded, as well as giveaways such as animation

software packages, resort trips and computer equipment.

     Please review these guidelines before sending your entry in:

     1.There are no restrictions on animation technique, no age limits or education requirements.All animated

films must be more than one minute long.

     2.All entries must be original and have received no major award before submitting to Ani-mazing.Both

computer and hand animation is accepted.

     3.Keep in mind that your animation will be viewed by an all-ages audience. Ani-mazing reserves the right

to reject entries containing inappropriate subject matter.

     4.More than one entries is allowed, however, all entries must be the work of nonprofessionals.Time

limits may prevent us from exhibiting all of the entries received, so please choose one animation to be your

primary entry. 

     5.All entries must be handed in by July 30.If you have trouble making this deadline, contact us and we

will consider extending the deadline for you.

     6.Please send a copy of your animation, not the original.We will not be able to return media to you.

     7.Your entry MUST include your name, age, educational background, contact information, and length

of the animation.

1. Why will the animation contest be held?

A. To collect works for an animation exhibition.

B. To attract more people to a course.

C. To find new animation talents.

D. To increase people' s awareness about animation.

2. Which of the following meets the requirements of the contest?

A. An animation made by hand.

B. An animation lasting 50 seconds.

C. An animation winning an award last year.

D. An animation downloaded from the Internet.

3. What is the deadline for entry?

A. September 27.

B. September 20.

C. July 30.

D. September 28.