Protected Mode - Toshiba T2150CD Series Manual

Protected Mode

Protected Mode was introduced with the 80286 microprocessor. The primary advantage of
protected mode is its ability to let the processor directly access all available memory.
In protected mode, all the instructions and architectural features are available to the
microprocessor, so all applications have access to the full range of extended memory.
Another benefit of protected mode is the processor's ability to allocate a predetermined
amount of memory to different applications and switch among them (multi-tasking). The
processor is responsible for protecting each of the applications in the system from one another.
Virtual 8086 Mode
This mode taps the real power of the DX4 processor. Virtual 8086 mode allows the DX4
processor to emulate real mode and still switch to and from protected mode. The processor
can load and execute real mode applications (in virtual 8086 mode), then switch to protected
mode and load and execute another application that requires access to the full extended
memory available. The microprocessor, together with a control program such as Windows,
assumes the responsibility of protecting applications from one another.