VirtualBox install on ubuntu

VirualBox 要安裝在 ubuntu上非常簡單

[Version]
Ubuntu 12.04
VirtualBox

[Steps]
1. Download VirtualBox package
2. sudo apt-get install dkms
3. sudo dpkg -i VirtualBox-3.2_4.1.16_Ubuntu_karmic_i386.deb

4. 要開啟virtualbox也很簡單, 只要在terminal上執行 virtualbox
    就會開啟圖形介面

[Reference]
https://www.virtualbox.org/manual/ch02.html#idp12629648