Real mode, also called real address mode, is an operating mode of all x86-compatible CPUs Real mode is characterized by a 20 bit segmented memory address space (giving exactly 1 MiB of addressable memory) and unlimited direct software access to all memory, I/O addresses and peripheral hardware. Real mode provides no support for memory protection, multitasking, or code privilege levels. Before the release of the 80286, which introduced Protected mode, real mode was the only available mode for x86 CPUs. In the interests of backwards compatibility, all x86 CPUs start in real mode when reset.
Read more about Real Mode: History, Addressing Capacity, A20 Line, Switching To Real Mode
Famous quotes containing the words real and/or mode:
“Surrealism, n. Pure psychic automatism, by which it is intended to express, whether verbally or in writing, or in any other way, the real process of thought. Thought’s dictation, free from any control by the reason, independent of any aesthetic or moral preoccupation.”
—André Breton (1896–1966)
“If Thought is capable of being classed with Electricity, or Will with chemical affinity, as a mode of motion, it seems necessary to fall at once under the second law of thermodynamics as one of the energies which most easily degrades itself, and, if not carefully guarded, returns bodily to the cheaper form called Heat. Of all possible theories, this is likely to prove the most fatal to Professors of History.”
—Henry Brooks Adams (1838–1918)