OEM Original equipment manufacturer. Used primarily to refer to PC systems manufacturers.
OnNow A design initiative that seeks to create all the components required for a comprehensive, system-wide approach to system and device power control. OnNow is a term for a PC that is always on but appears off and that responds immediately to user or other requests.
OpenGL An operating system independent, industry-standard API for 3-D color graphics programming. Typically used for engineering, visualization, simulation, and other graphics-intensive applications.
option ROM Also expansion ROM. Optional read-only memory found on an expansion card. Option ROMs usually contain additional firmware required to properly boot the peripheral connected to the expansion card, for example, a hard drive.
OR A logical operation for combining two bits or two Boolean values. If one or both values are true, it returns the values of true. Compare with XOR.