In z/OS, paging and swapping are two mechanisms used to manage memory and processes efficiently. While they may seem similar, they serve different purposes and operate in distinct ways.

Paging is a memory management scheme that eliminates the need for contiguous allocation of physical memory. This technique allows the physical address space of a process to be noncontiguous. z/OS divides a program into fixed-size blocks, known as pages, typically 4KB each. When a program is executed, not all pages may be loaded into central storage; instead, they are brought in as needed. Pages that are not actively used are moved to auxiliary storage, which is a slower type of memory like a disk. This process is transparent to the user and is managed by z/OS, which uses a "Least Used" algorithm to determine which pages to swap in and out of central storage².