How does virtual memory use persistent storage?

Virtual memory uses persistent storage by temporarily storing data from RAM onto the hard drive.

Virtual memory is a memory management technique where secondary storage devices, such as hard drives or solid-state drives, are used to extend the capacity of the computer's primary memory or random access memory (RAM). When the RAM is full or nearly full, the operating system moves some of the data or programs from RAM to the hard drive, creating space for new data or programs to be loaded into RAM. This process is known as swapping or paging.

The area of the hard drive that is used for this purpose is called the swap file or page file. The operating system manages this file, deciding what data to move to it and when. This is done in such a way that the user is not aware of it, and it appears as though there is more RAM available than there actually is.

The use of virtual memory allows for more efficient use of the computer's physical memory, as it can hold more programs and data than would otherwise be possible. It also allows for the execution of programs that are larger than the available RAM. However, because accessing data on the hard drive is slower than accessing data in RAM, the use of virtual memory can slow down the computer if it is used too frequently or if the hard drive is slow.

In summary, virtual memory uses persistent storage to extend the capacity of the computer's primary memory. It does this by temporarily storing data from RAM onto the hard drive, freeing up space in RAM for new data or programs. This process is managed by the operating system and is done in such a way that it is transparent to the user.