Page Fault

Definitions

1. An interrupt triggered when a program accesses a virtual memory page that isn't currently mapped to physical RAM. Minor page faults load the page from the page cache (fast). Major page faults must read from disk (slow — orders of magnitude slower). Excessive major page faults indicate the system is thrashing.

   In plain English: When a program tries to access memory that isn't loaded yet, causing the OS to fetch it — slow if it has to read from disk.

   Example: "The process is thrashing — 50,000 major page faults per second because the working set exceeds available RAM."

Related Terms

• Swap
• Cache
• Memory Allocation
• Thread
• Apache Arrow
• Memory Pool
• Context Switch
• Memory Leak
• CPU Cache
• Lazy Initialization
• Page Cache
• Random Access
• String Builder