CPU 环, 优先级和保护 CPU Rings, Privilege, and Protection
CPURings,Privilege,andProtectionCPU环,特权级和保护机制YouprobablyknowintuitivelythatapplicationshavelimitedpowersinIntelx86computersandthatonlyoperatingsystemcodecanperformcertaintasks,butdoyouknowhowthisreall