The Protected Virtual Address Mode was originally implemented in the 80286 to protect (as its name suggests) the different tasks in a multitasking operating system from invalid or incorrect accesses. For this purpose, the processor hardware checks all the data and code accesses made by a program and uses four privilege levels to provide access rights for such accesses. Thus, data and code are protected and a complete system crash of the PC is supposedly impossible. In practice, under Windows it has proved that this is indeed possible. Since this is not definitely the case under GNU/Linux, you might ask whether Windows also complies with the Intel protected mode guidelines
The Indispensable PC Hardware Book, 4th edition, Hans-Peter Messmer, pp. 144-145 pwned
