（总共有300分，能在星期二晚上之前搞好的300分全数奉上，可是这里怎么只能给100- -？）
Lesson Nine
The Model layers of DSA
The Model is made up of several basic layers
1:Applications Layer
The services provided BY this layer depend upon the particular application being considered.In turn it will determine the service to be provided by the lower layers.
There are few distributed applications in the true sense,although the following design areas can be identified as important.
1:Application structure,in which the important questions are:How should processing be distributed ? How Should application processes be
organized for control and communication? How should data be distributed ? what mechanisms are required to support different data and processing organizations?
2:Language issues,in particular what language features are necessary to support distuibuted processing beyond those required in languages that are used in uniprocessor systems.One possible objective
of any such languages would be to provide a view from whicn the system
appears to be non-distributed to user .A further requirement may be to give the user the ability to specify the placement of data and its visibility hence providing both control and performence.
剩下100分如果星期二之前有人解答，就奉上咯，反正是偶全部的分数
参考资料：纯手工翻译。