So what exactly is real addressing mode?
As mentioned earlierI when an x86 system is powered up or UHsHW, LW Ls Ln UHDO PRGH. ,I yRX wRnGHUHG wKy WKLs Ls sR, LW’s because in the real addressing modeI an x86 system becomes backward compatible with all previous x86 chipsI and thus allows the BIlS and other prehistoric software to run. 8M86I the nRWDEOH 16-ELW PLFURSURFHssRU IURP ,nWHO DnG WKH vHUy fiUsW wLWK the x86-architectureI while implementing memory segmentation, operates only in real mode. SoftwareI in real modeI can directly access all memoryI ILl addresses and hardware peripherals; howeverI the memory that can be addressed is limited to only OOM bytesI i.e.I only 1 MB of memory can be addressed. curtherI the entire 1 MB of memory cannot be active at the same time but partitions of 64 KB segments can. bach segment has its own starting address and is numbered from MMMMMH to cccccH.