A computer system and method for operating a computer system capable of running in mutually incompatible real and protected addressing modes, in which programs written for one mode can be run in the other mode without modification. The BIOS assembles two different common data areas for the two modes,...http://www.google.com.tw/patents/US5193161?utm_source=gb-gplus-share專利 US5193161 - Computer system having mode independent addressing
