(1) An operational state that a system has been switched to. It implies at least two possible conditions. There are countless modes for hardware and software. With regard to modes on a hard drive (Mode 2, Mode 3, etc.), see
IDE. See
Real Mode,
Protected Mode,
burst mode,
insert mode,
supervisor state and
program state.
(2) In fiber optics, the reflective path taken by light in a fiber. Each mode has its own pattern of electromagnetic fields as it propagates through the fiber. From a cross section of the fiber, these modes can be viewed as multiple headlights beaming at you. In multimode fiber, multiple modes are generated, causing pulse dispersion at the receiving end. See
multimode fiber,
dispersion and
fiber optics glossary.