By MySQL pages i mean this :

https://dev.mysql.com/doc/internals/en/innodb-page-structure.html

and operating system pages :

https://en.wikipedia.org/wiki/Page_(computer_memory)

I understand both of them, but i don't understand their relation, so DBMS is basically a program that runs on top of our O.S correct? so why are DBMSes like MySQL don't just use the page size of the operating system and instead let the DBA decide what should the page size be?

what happens when the O.S page size is 8KB but DBMS is 16KB? and what if its vice versa?

By MySQL pages i mean this :

https://dev.mysql.com/doc/internals/en/innodb-page-structure.html

and operating system pages :

https://en.wikipedia.org/wiki/Page_(computer_memory)

I understand both of them, but i don't understand their relation, so DBMS is basically a program that runs on top of our O.S correct? so why are DBMSes like MySQL don't just use the page size of the operating system and instead let the DBA decide what should the page size be?

what happens when the O.S page size is 8KB but DBMS is 16KB? and what if its vice versa?

Does a difference between these two affect performance or anything else?