1. Others SO
   1. Ubuntu
   2. Unix
   3. Mac OS X
2. Generic is
   1. Multitasking
3. Must have
   1. Command line interface
   2. Graphical user Interface
4. Can
   1. Device drivers
   2. Log on
      1. Log off
   3. Format
   4. Compression
5. More popular
   1. Microsoft
      1. Windows Seven
      2. Windows xp
      3. Windows 98
      4. Windows 2000
6. Virtual Machine
   1. Why
      1. Virtual Box
7. More important in one computer
8. Hearth
   1. Kernel
      1. Responsible
         1. All the most Basic task