Virtual Memory: Your Program Lives in a Fantasy World

https://www.youtube.com/watch?v=XZFdkQ_y0-M title: "Virtual Memory: Your Program Lives in a Fantasy World" published: true tags: virtualmemory, operatingsystems, computerscience, programming Your program thinks it owns all the memory on your computer. It doesn't. Not even close. When your code allocates an array, it gets an address like 0x7FFF0000. It reads from it, writes to it, treats it like physical RAM. But that address is a lie. It doesn't point to a real location in hardware. It points to a virtual address — a fake address your operating system invented. Every program on your machine lives in its own virtual address space. Each one believes it has 256 terabytes of memory all to itself. On a machine with 16 GB of actual RAM. This is virtual memory. And without it, modern computing wouldn't exist. Pages: The Unit of Illusion The OS doesn't map individual bytes — that would require a translation table bigger than memory itself. Instead, it splits memory into fixed-size chunks calle