Free list

A free list is like a list of toys that you can play with. But instead of toys, it's a list of stuff in a computer's memory that is not being used by any programs right now.

Imagine that your computer has a toy box with a limited amount of space. Whenever you play with a toy, it takes up some space in the toy box. But when you stop playing with that toy, it goes back into the box and frees up space for new toys.

Similarly, when a program uses some space in a computer's memory, it takes up that space like a toy in the toy box. But when the program is done using that space, the memory becomes free again, just like a toy going back into the toy box.

The free list is like a list of all of the memory space that is currently free and can be used by other programs. It's like a list of free toys that you can play with if you want to.

So when a new program needs some memory space to do its work, it can look at the free list to see if there is any available memory that it can use. If there is, it can take some of that space and start using it, just like taking a toy out of the toy box to play with it.

And just like when you put a toy back in the toy box and it becomes available for other kids to play with, when a program stops using a piece of memory space, it goes back into the free list for other programs to use.