An execution
mode supported by the Intel 80286 and later
processors. In real mode, these processors imitate the Intel 8088 and
8086 microprocessors, although they
run much faster. The other mode available is called
protected mode. In protected mode,
programs can
access extended memory and
virtual memory. Protected mode also supports
multitasking. The 80386 and later microprocessors support a third mode called
virtual 8086 mode. In virtual mode, these microprocessors can run several real-mode programs at once.
The DOS operating system was not designed to take advantage of protected mode, so it always executes programs in real mode unless a protected mode extender is run first.
