Can you explain the concept of physical memory in computer systems?

Physical memory is a real hardware resource of a computer, usually RAM, where data and instructions that the processor works with are stored. It is represented by a set of cells, each with a unique address.

In computer systems, physical memory is managed by the operating system, which allocates it among processes. For convenience and security, virtual memory is often used — an abstraction that allows processes to work with their own address space, which is mapped to physical memory.

Example: when a program requests memory, the OS allocates blocks of physical memory to it, but the program itself only sees virtual addresses, which the OS translates into physical addresses.

Thus, physical memory is the foundation for storing data and code, and managing it ensures efficient and secure operation of programs.