(1) In the virtual-memory system, faults are the mechanism for initiating page-in activity. They are interrupts that occur when code tries to access data at a virtual address that is not mapped to physical memory. Soft faults happen when the referenced page is resident in physical memory but is unmapped. Hard (or page) faults occur when the page has been swapped out to backing store. See also page, virtual memory. (2) A type of object in Enterprise Objects that represents a partially formed enterprise object instance. Faults are proxy or stand-in objects that provide performance benefits by delaying the retrieval of data in an enterprise object until it’s absolutely needed.