Imagine you have a group of friends who all want to play with the same toy. But everyone wants to use it at the same time, which could be a problem. So, you all come up with a plan to take turns and share the toy fairly.
In computers, programs also need to take turns using resources to ensure that everyone can use them without conflicts. This is where the idea of global serializability comes in. It's like having a plan for the different programs to share resources in an orderly way, just like friends sharing a toy.
Global serializability ensures that all transactions (some work a program does on data) happen in a coordinated way, just like all friends taking turns with the toy. This means that no program will try to use a resource that is already being used by another program, and all the programs will behave in a predictable and orderly way.
So, to sum up, global serializability is a way to ensure that different programs can share resources by taking turns in an organized and coordinated way, just like friends playing with a toy.