昨天论坛一个朋友问起http://download.eclipse.org/eclipse/downloads/drops/R-3.7-201106131736/winPlatform.php这页面的内容，每个部分都是干什么的。这里简单的整一下。
其实很简单，这个页面就是介绍了在Eclipse Project在Windows平台下，提供了哪些可供下载的包。
这个就是Eclipse SDK，170M，分为Windows 32位和64位两种。Windows64位一般会用x86_64标识。
除了最常用的Eclipse SDK以外，还有很多包可以单独下载：
对于Eclipse 小组来说，每一个组成Eclipse的部分都是独立，都可以单独运行，所以在下载的页面，很多常用的包都可以单独下载，比如Runtime Binary：
下面一一讲解下每个包的作用：
Eclipse SDk
Eclipse的发行包，一般用户直接下载这个包就可以开发了，它包含了很多常用的包，比如Platform SDK，JDT SDK，RCP SDK，CVS，JUnit等等
JUnit Plugin Tests and Automated Testing Framework
这个是JUnit相关的包
Example Plug-ins
Eclipse提供了很多Example，它们仍然以plugin的方式提供给用户，可以通过Help -> Install New Software直接下载
RCP Runtime Binary
Eclipse本身也是一个RCP，如果仅仅关心RCP本身，而且不包含源码，可以使用这个包
RCP SDK
SDK全称为Software Development Kit，软件开发包，一般会包含api以及源码，RCP SDK包含了RCP开发的基础源码和api说明
DeltaPack
The delta pack contains all the platform specific resources from the SDK and is used for cross-platform exports of RCP applications. 这个不太清楚是干嘛的，估计与跟平台移植相关
com.ibm.icu.base binary and source Plug-ins
这个也不清楚 - -
Platform Runtime Binary
Eclipse Platform的运行时，其实这就是一个最简单的Eclipse了，只有50M
Platform SDK
Eclipse Platform的SDK，相对于Runtime，多了一些源码和api说明
JDT Runtime Binary
Java Development Toolkit 运行时，开发Java的必要环境，Eclipse Platform必须要包含JDT才能进行Java开发
JDT SDK
Java Development Toolkit 的SDK
JDT Core Batch Compiler
These drops contain the standalone batch java compiler, Ant compiler adapter and associated source. The batch compiler and Ant adapter (ecj.jar) are extracted from the org.eclipse.jdt.core plug-in as a 1.2MB download. For examples of usage, please refer to this help section: JDT Plug-in Developer Guide>Programmer's Guide>JDT Core>Compiling Java code.不太了解，有兴趣的自己看看
Jar Processor
These drops contain the standalone jar processor and associated source. The jar processor is extracted from org.eclipse.update.core.
PDE Runtime Binary
PED又是一个很重要的东西，全称 Plug-in Development Environment (PDE) ，provides tools to create, develop, test, debug, build and deploy Eclipse plug-ins, fragments, features, update sites and RCP products.
PDE UI，PDE主要用来方便用户进行Plugin开发，它提供了很多UI，比如
- Form-Based Manifest Editors: Multi-page editors that centrally manage all manifest files of a plug-in or feature.
- RCP Tools: Wizards and a form-based editor that allow you to define, brand, test and export products to multiple platforms.
- New Project Creation Wizards: Create a new plug-in, fragment, feature, feature patch and update sites.
- Import Wizards: Import plug-ins and features from the file system.
- Export Wizards: Wizards that build, package and export plug-ins, fragments and products with a single click.
- Launchers: Test and debug Eclipse applications and OSGi bundles.
- Views: PDE provides views that help plug-in developers inspect different aspects of their development environment.
- Miscellaneous Tools: Wizards to externalize and clean up manifest files.
- Conversion Tools: Wizard to convert a plain Java project or plain JARs into a plug-in project.
- Integration with JDT: Plug-in manifest files participate in Java search and refactoring.
PDE SDK
PDE的SDK
CVS Client Runtime Binary
CVS版本控制的运行时
CVS Client SDK
SWT Binary and Source
SWT的运行时和源码
org.eclipse.releng.tools plug-in
Eclipse Releng工具，很强大，更多信息参考http://wiki.eclipse.org/Platform-releng-faq