What is the difference between the 80286 real address mode and PVAM? Explain how these two modes can be switched back and forth?

Answer:

            Difference between Real address mode and PV AM:-

Real Address mode:

            If the 80286 is operating in the real address mode, the address unit computer address using a segment base and an offset. The maximum physical address space n this mode is 1 Mbyte, Just as it is for the 8086.

After the 80286 is reset, it starts executing in its real address mode. Due to the extenments, the 80286 will execute most programs several times faster than an 8086 with the same frequency clock signal. When operating in real address mode, the interrupt vector table of the 80286 is located in the first 1 kbyte of memory.

Protected virtual address mode(PVAM):-

            If the 80286 is operating in its protected virtual address mode (Protected mode) the address unit functions as a complete MMu. In this address mode the 80286 uses all 24 address lines to access up to 16 Mbytes of physical memory. If an 80286- based system is running an operating system such as Microsoft’s Os/2, which uses the protected mode. Switching an 80286 to protected mode enables the integrated MMu to provide virtual memory and protection.