Page Fault
An exception raised when a process accesses a virtual-memory page that is not currently mapped with the required permissions or physical backing.
Operating-System Context
A page fault occurs when an access cannot be satisfied by the current virtual-memory mapping. A minor fault can establish a mapping without storage I/O, while a major fault may need to fetch data from storage; demand paging and memory-mapped files rely on this mechanism.
Error Boundary
A page fault is not necessarily an application defect. Many faults are normal events in virtual-memory management, although invalid access or permission faults can also terminate a process.
Related Operating-System Concepts
- Virtual Memory
- Memory-Mapped I/O
- TLB
- Page Cache