Mmap

Mmap, short for memory mapped files, is like having a special book where you can read and write on every page, even if the book is very big. And instead of holding words and paragraphs, each page has some numbers.

Imagine you have a very big book of numbers containing billions of them. If you wanted to find a specific number on page 456, you would have to flip through every page until you reached page 456. This takes a lot of time and effort, especially if the book is very big.

But with mmap, you don't need to do that. You can open the book, find the page you want, and write or read the numbers on it without needing to flip through all the pages in between. It's like a shortcut.

This can be very useful if you are working with very large files, like image or video files, that would take a very long time to load and process using traditional methods. By using mmap, you can load only the part of the file you need, without having to load the entire file into memory at once.

Overall, mmap is a way to quickly and efficiently access specific parts of a file without needing to read or write the entire file at once. It's like having a magic book where you can access any page instantly, without having to read all the pages in between.