DVI Connector information

DVI full name is Digital Visual Interface

What is DVI-A, DVI-I and DVI-D, what is the difference?

 - DVI-A is support analog only.

 - DVI-D is support Digital only, you only can use adaptor to change HDMI or Display Port only.

 - DVI-I is support Digital and Analog.

Single Link vs Dual Link

 - Single Link support 1920 × 1200 (WUXGA) @ 60 Hz

 - Dual Link support 2560 × 1600 (WQXGA) @ 60 Hz or 1920 × 1200 (WUXGA) @ 120 Hz

 - Analog video stream: 1920 × 1200 (WUXGA) @ 60 Hz

DVI vs HDMI

 - HDMI is newer interface and it include Video & Audio Signal, DVI only support Video Signal.

DVI Cable Length Limited

 - 15 feet (1920x1200) to 50 feet (1280x1020)

Upgrade to Windows 10 downgrade to Windows 7 / 8

不小心升級了Windows 10，原來可輕鬆地還原回前一個版本。

限制 : 

 - 升級一個月內可以還原回Windows 7 / 8

 - 如Windows 10內作出左大量使用者帳戶的修改可能會導致不能還原

注意 : 
 - Windows 升級時會把原有的Windows, Program Files & User folder存放到Windows.old資料夾內，如內裹資料被刪除會不能還原
 - 升級時本來的使用者內的所有資料會遷移到新的Windows Profile內，當Downgrade時會把資料遷移回舊Windows Profile內，但請事先備份Profile內的所有資料，我已試過還原時Profile內的資料全數失踪。

Source From : http://www.howtogeek.com/220723/how-to-uninstall-windows-10-and-downgrade-to-windows-7-or-8.1/

1. Press Start > Settings > Update & Security > Recovery >  "Get Started" for Go Back to Windows 7/8

2. Waiting "Getting things ready", if can't start, it will tell you the reason and you should follow up the instruction to fix the problem. (e.g. such as you add the new user on windows 10.)

3. Waiting restore to Windows 7 / 8.