MIT-SHM, or MIT Shared Memory, is like a magical invisible piece of paper that two or more people (or processes) can write and draw on at the same time. This magical paper is kept in a special place in the computer called shared memory.
Let's say you and your friend both want to draw a picture, but you only have one piece of paper. You could take turns drawing on the paper, but that would be kinda boring. Instead, you ask your mom to get you some special paper that allows you and your friend to draw on it at the same time. This special paper is the shared memory.
When you and your friend want to draw on this magical paper, you ask your mom to tear off a piece of paper and give one to each of you. You both can draw on your own piece of paper, but because it's the same magical paper, whatever you draw on your own piece of paper will also show up on your friend's piece of paper. This is like when you and your friend are drawing together on an Etch A Sketch or a Magna Doodle.
In computer terms, programs use shared memory to share data with each other. This means that two programs can write and read from the same piece of memory, like you and your friend drawing on the same magical paper. This is useful when programs need to quickly pass data back and forth without having to save it and reload it from a file or a network connection each time.
MIT-SHM is a special kind of shared memory that was developed at MIT (the Massachusetts Institute of Technology). It's like a super fast and efficient way for programs to share data with each other. Kind of like a secret code that only cool kids from MIT know.