下载了Linux Mint 15 "Olivia" , 在Virtual Box 安装的时候，总是停在start linux mint 上，一直没有反应，试了N多次。
PAE = Physical Address Extension 物理地址扩展
扩展32位操作系统的内存地址长度到36位, 以使用4G以上的内存, 最高支持64G内存
NX = NoExecute 一种硬件执行数据保护技术, 通过将内存地址标识为'不可执行', 防止恶意代码及病毒运行
还有虚拟机内存分配的时候，我分配的是1024M，据说少于1024M的话，不能进入图形界面，我在一个windows 7 的系统上安装Ubuntu 12.04 的时候碰见过，后来掉整了内存大小，就进入了图形界面了。
The purpose of Linux Mint is to produce a modern, elegant and comfortable operating system which is both powerful and easy to use.
Started in 2006, Linux Mint is now the 4th most widely used home operating system behind Microsoft Windows, Apple Mac OS and Canonical's Ubuntu.
Some of the reasons for the success of Linux Mint are:
It works out of the box, with full multimedia support and is extremely easy to use.
It's both free of cost and open source.
It's community-driven. Users are encouraged to send feedback to the project so that their ideas can be used to improve Linux Mint.
Based on Debian and Ubuntu, it provides about 30,000 packages and one of the best software managers.
It's safe and reliable. Thanks to a conservative approach to software updates, a unique Update Manager and the robustness of its Linux architecture, Linux Mint requires very little maintenance (no regressions, no antivirus, no anti-spyware...etc).