Type of mouse that has a ball located on the bottom that rolls around on a flat surface as the mouse is moved. Sensors inside the mouse determine the direction and distance of the movement - Input. Optical mouse. Type of mouse that uses a laser to detect the mouse's movement and has no moving parts - Input.
The Strategic Defense Initiative (SDI) was a proposed missile defense system intended to protect the United States from attack by ballistic strategic nuclear weapons (Intercontinental ballistic missiles and Submarine-launched ballistic missiles).
IFI may refer to: Illinois Family Institute. Industrial Fasteners Institute, the Independence, Ohio based trade and standards organization and publisher. InnerChange Freedom Initiative (IFI), a Christian prisoner program. The International Federation of Interior Architects/Designers (IFI), a global interior architecture/design umbrella organization.