Virtuaaliosoitteiden

Virtuaaliosoitteet, also known as virtual addresses, are memory addresses used by a process. When a program runs, it interacts with a virtual memory space rather than directly with the physical hardware. This virtual space is a logical representation of memory that the operating system provides to each process. The operating system and the processor's memory management unit (MMU) work together to translate these virtual addresses into physical addresses in RAM.

This abstraction offers several advantages. Firstly, it allows for memory protection, preventing one process from interfering with the memory of another. Each process has its own isolated virtual address space. Secondly, virtual memory enables processes to use more memory than is physically available in RAM through techniques like paging and swapping, where less frequently used parts of memory are moved to secondary storage. Thirdly, it simplifies programming by providing a consistent and large address space, regardless of the actual physical memory layout.

When a program accesses a virtual address, the MMU checks if the corresponding physical page is in RAM. If it is, the translation is straightforward. If not, a page fault occurs, and the operating system intervenes to retrieve the required data from disk and load it into RAM, potentially swapping out another page to make space. This entire process is transparent to the running program, which continues to operate using virtual addresses.