Codex Gamicus
Real Mode
Basic Information

Real Mode is an operating mode present on all x86 processors since the Intel 80286 that allows them to appear to software as an Intel 8086 while still maintaining clock speed. In this mode, the processor is limited to processing only 16-bit instructions, and is only capable of addressing the first 1 MB of RAM. When installed, some versions of MS-DOS must operate under Real Mode.

Windows 95 and Windows 98 include virtualization drivers that can approximate Real Mode to MS-DOS applications via MS-DOS Compatability Mode; these drivers were not present in Windows ME.