How do programs use memory?

So, we know that a process has a chunk of memory dedicated for its execution. But, how does it access this memory to perform its task? For security purposes and fault isolation, a process is not allowed to access the physical memory directly. Instead, it uses a virtual memory, which is mapped to the actual physical memory by the OS using an in-memory data structure called pages, which are maintained in page tables. The process has to request memory from the OS for its use, and what it gets is a virtual address that is internally mapped to a physical address in the RAM. For performance reasons, this memory is requested and processed in chunks. When virtual memory is accessed by the process, the memory management unit does the actual conversion from virtual to physical memory.

The whole series of steps through which memory is acquired by a process from the OS is known as memory allocation. A process requests a chunk of memory from the OS by using system calls, and...