计算机软件领域中Layer 与 Tier(不是tire) 的区别

在计算机软件领域，Layer与Tier都有”层”的意思，翻译为中文，也都是”层”。但根据MSDN上的文章所述，这两个词的具体所指还是有区别的，一般认为,Layer指逻辑层，如我们通常据说的”三层架构”：UI(or Presentation) Layer, Business Logic Layer，Data Access Layer。而tier指物理层。然而，也有不遵循这个规则的，如Business Tier，Data Access Tier，当然，这样写的人可能说的是业务层(Business Tier)代码与数据访问层(Data Access Tier)代码在不同的物理位置。

下面是摘自Developer's Guide to EnterpriseLibrary 5 RC文档中第75页的一段话：

For simplicity, this example shows the principles of exception shielding at the level of the UI view.

The business functionality it uses may be in the same layer, in a separate business layer, or even on

a separate physical tier. Remember that you should design and implement an exception handling

strategy for individual layers or  tiers in order to shield exceptions on the layer or service

boundaries.

 

下面是摘自EntLib50-combined(chm格式)文档中What Does the Exception Handling Application Block Do?

节：

This pattern ensures that your application does not leak sensitive information, no matter what run-time
or system event may occur to interrupt normal operation. And on a more granular level, it can prevent your
assets from being revealed across layer,tier,process, or service boundaries.

  

         来自en.wikipedia.org:     
       A layer is a   logical       structuring mechanism for the elements that make up your software solution;
         A tier is a    physical     structuring mechanism for the system infrastructure