当我们下载CentOS 7 时会发现有几个版本可以选择，如下：
1、CentOS-7-DVD版本：DVD是标准安装盘，一般下载这个就可以了。
2、CentOS-7-NetInstall版本：网络安装镜像。
3、CentOS-7-Everything版本：对完整版安装盘的软件进行补充，集成所有软件。
4、CentOS-7-LiveGnome版本：GNOME桌面版。
5、CentOS-7-KdeLive版本：KDE桌面版。
6、CentOS-7.0-livecd版本：光盘上运行的系统，类拟于winpe
其实在README中对这几种版本做了介绍，以下是原文及其翻译：
List of images in this directory
================================
CentOS-7-x86_64-DVD-1804.iso
This DVD image contains all the packages that can be installed using the
installer. This is the recommended image for most users.CentOS-7-x86_64-NetInstall-1804.iso
This is the network install and rescue image. The installer will ask from
where it should fetch the packages to be installed. This image is most
useful if you have a local mirror of CentOS packages.CentOS-7-x86_64-Everything-1804.iso
This image contains the complete set of packages for CentOS Linux 7. It can be
used for installing or populating a local mirror. This image needs a 16GB USB
flash drive as it is too large for DVD isos.CentOS-7-x86_64-LiveGNOME-1804.iso
CentOS-7-x86_64-LiveKDE-1804.iso
These images are Live images of CentOS Linux 7. Depending on the name they use the respective display manager. They are designed for testing purposes and exploring the CentOS Linux 7 environment. They will not modify the content of your hard disk, unless you choose to install CentOS Linux 7 from within the Live environment. Please be advised that you can not change the set of installed packages in this case. This needs to be done within the installed system using 'yum'.CentOS-7-x86_64-Minimal-1804.iso
The aim of this image is to install a very basic CentOS Linux 7 system, with the minimum of packages needed to have a functional system. Please burn this image onto a CD and boot your computer off it. A preselected set of packages will be installed on your system. Everything else needs to be installed using yum. The set of packages installed by this image is identical to the one installed when choosing the group named "Minimal" from the full DVD image.Using the installation images
=============================You can burn these images to a DVD or 'dd' them to a USB flash drive.
After the boot media has been prepared, boot the computer off the boot media. If you do an install to your hard disk using these installation images, please remember to run "yum update" after the installation to update your system to the latest packages.Remember that in order to be able to partition your disk you will need to run
the GUI installer which in turns needs enough RAM. The same is true for the
network setup step. Please refer to the release notes available at
http://wiki.centos.org/Manuals/ReleaseNotes/CentOS7 for more details about
these aspects.
翻译如下：
这个文件夹下的images
================================
CentOS-7-x86_64-DVD-1804.iso
这个DVD image包含了可以使用下载器下载的所有包。想使用CentOS的小伙伴都可以下载这个image，面向大部分用户。CentOS-7-x86_64-NetInstall-1804.iso
这是网络安装和救援image。安装人员会询问应该从哪里获取要安装的软件包。如果您有CentOS软件包的本地镜像，则非常有用。CentOS-7-x86_64-Everything-1804.iso
这个image包含Centos Linux 7完整的软件包，可用于安装或填充本地镜像。此图像需要16GB USB 闪存，因为它太大了（9G）。CentOS-7-x86_64-LiveGNOME-1804.iso
CentOS-7-x86_64-LiveKDE-1804.iso
这些images是CentOS Linux 7的Live image。根据名称，它们使用相应的显示管理器。它们专为测试目的和探索CentOS Linux 7环境而设计。除非您选择从Live环境中安装CentOS Linux 7，否则它们不会修改硬盘的内容。请注意，在这种情况下，您无法更改已安装的软件包集。这需要使用yum在已安装的系统中完成。CentOS-7-x86_64-Minimal-1804.iso
这个image的目的是安装一个非常基本的CentOS Linux 7系统，只需要最少的软件包即可拥有一个功能系统。请将此图像刻录到CD上并启动计算机。系统上将安装一组预先选择的软件包。其他所有东西都需要使用yum安装。此映像安装的软件包集与从完整DVD映像中选择名为“Minimal”的组时安装的软件包相同。当你使用安装镜像时
=============================
您可以将这些图像刻录到DVD或dd它们到USB闪存驱动器。 准备好引导介质后，从引导介质引导计算机。如果使用这些安装映像对硬盘进行安装，请记住在安装后运行yum update以将系统更新到最新的软件包。请记住，为了能够对磁盘进行分区，您需要运行 GUI安装程序又需要足够的RAM。这同样适用于 网络设置步骤。请参阅可用的发行说明 http://wiki.centos.org/Manuals/ReleaseNotes/CentOS7了解更多详情这些方面。
