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Part of a series on
Microprocessor modes for the x86 architecture
Real mode (Intel 8086)
8080 emulation mode (NEC V20/V30 only)
Protected mode (Intel 80286)
Unreal mode (Intel 80286)
Virtual 8086 mode (Intel 80386)
System Management Mode (Intel 386SL)
Long mode (AMD Athlon 64)
x86 virtualization (Intel Pentium 4, AMD Athlon 64)
AIS mode (VIA C3 only)
First supported platform shown in parentheses
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Real mode, also called real address mode, is an operating mode of all x86-compatible CPUs. The mode gets its name from the fact that addresses in real mode always correspond to real locations in memory. Real mode is characterized by a 20-bit segmented memory address space (giving 1 MB of addressable memory) and unlimited direct software access to all addressable memory, I/O addresses and peripheral hardware. Real mode provides no support for memory protection, multitasking, or code privilege levels.
Before the introduction of protected mode with the release of the 80286, real mode was the only available mode for x86 CPUs;[1] and for backward compatibility, all x86 CPUs start in real mode when reset, though it is possible to emulate real mode on other systems when starting in other modes.
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Realmode, also called real address mode, is an operating mode of all x86-compatible CPUs. The mode gets its name from the fact that addresses in real...
In x86 computing, unreal mode, also big realmode, flat realmode, or voodoo mode is a variant of realmode, in which one or more segment descriptors has...
microprocessor and later, virtual 8086 mode (also called virtual realmode, V86-mode, or VM86) allows the execution of realmode applications that are incapable...
When a processor that supports x86 protected mode is powered on, it begins executing instructions in realmode, in order to maintain backward compatibility...
processors support five modes of operation for x86 code, RealMode, Protected Mode, Long Mode, Virtual 86 Mode, and System Management Mode, in which some instructions...
in 64-bit mode. In both real and protected modes, the system uses 16-bit segment registers to derive the actual memory address. In realmode, the registers...
32 (0–31 or 0x00–0x1F) of which are used for processor exceptions. In realmode, the interrupt table is called IVT (interrupt vector table). Up to the...
mode, while 32-bit programs and 16-bit protected mode programs are executed in a sub-mode called compatibility mode. Realmode or virtual 8086 mode programs...
in 64-bit mode. Note: The ?IL registers are only available in 64-bit mode. Real Address mode, commonly called Realmode, is an operating mode of 8086 and...
showed the first real changes from Windows 98, including importing much of the look-and-feel from Windows 2000, and the removal of real-mode DOS. Industry...
typically sets up a realmode interrupt handler at this vector that provides video services. Such services include setting the video mode, character and string...
inaccessible to other operating modes of the CPU by the firmware. System Management Mode can address up to 4 GB memory as huge realmode. In x86-64 processors,...
VBE provide only a realmode interface, which cannot be used without a significant performance penalty from within protected mode operating systems. Consequently...
(or must) be used in realmode to set up and switch to protected mode, and a few (such as SMSW and LMSW) are useful for realmode itself. The Intel 80286...
the mode spacing of the laser, Δν = 1/τ. The duration of each pulse of light is determined by the number of modes oscillating in phase (in a real laser...
this is exclusive to the case where protected-mode drivers or DOS extenders are used; as a real-mode OS, the system runs with effectively no protection)...
Windows, version 2.0, was released on December 9, 1987, and used the real-mode memory model, which confined it to a maximum of 1 megabyte of memory....
debugging. The 80386 featured three operating modes: realmode, protected mode and virtual mode. The protected mode, which debuted in the 80286, was extended...
NLS, CP 437.NLS, UNICODE.NLS, LOCALE.NLS - Keyboard layouts RMM.PDR - RealMode Mapper Virtual Device The system may also use CONFIG.SYS, which contains...
virtual 8086 mode to run in Windows. 32-bit x86 processors themselves have two legacy modes: realmode and virtual 8086 mode. Realmode causes the processor...
VGA text mode was introduced in 1987 by IBM as part of the VGA standard for its IBM PS/2 computers. Its use on IBM PC compatibles was widespread through...
DOS commands such as DIR would show long file names as well. Some small realmode Dos programs have also been written over the years, although many have...
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