ELI5: Explain Like I'm 5

real mode

Real Mode is a type of operating system that was used in older computer systems. It's called real mode because it lets the computer access the computer's memory directly, rather than using special tools like in modern operating systems. In real mode, the computer can access all of its memory directly, which allows it to use more of its power and run programs more quickly. It also makes it easier for older programs to run on newer computers, since the real mode doesn't do any extra processing and doesn't have the same performance restrictions as modern operating systems. Real mode is still used in some older computers, but it's no longer the main way computers are used today.