What is Page Fault?

The term “page miss” or “page fault” refers to a situation where a referenced page is not found in the main memory.

When a program tries to access a page, or fixed-size block of memory, that isn’t currently loaded in physical memory (RAM), an exception known as a page fault happens. Before enabling the program to access a page that is required, the operating system must bring it into memory from secondary storage (such a hard drive) in order to handle a page fault.

In modern operating systems, page faults are a common component of virtual memory management. By enabling programs to operate with more data than can fit in physical memory at once, they enable the efficient use of physical memory. The operating system is responsible for coordinating the transfer of data between physical memory and secondary storage as needed.

What is Demand Paging in Operating System?

The concept of query navigation in the operating system. This concept says that we should not load any pages into the main memory until we need them, or keep all pages in secondary memory until we need them.

Similar Reads

What is Demand Paging?

Demand paging can be described as a memory management technique that is used in operating systems to improve memory usage and system performance. Demand paging is a technique used in virtual memory systems where pages enter main memory only when requested or needed by the CPU....

What is Page Fault?

The term “page miss” or “page fault” refers to a situation where a referenced page is not found in the main memory....

What is Thrashing?

Thrashing is the term used to describe a state in which excessive paging activity takes place in computer systems, especially in operating systems that use virtual memory, severely impairing system performance. Thrashing occurs when a system’s high memory demand and low physical memory capacity cause it to spend a large amount of time rotating pages between main memory (RAM) and secondary storage, which is typically a hard disc....

Pure Demand Paging

Pure demand paging is a specific implementation of demand paging. The operating system only loads pages into memory when the program needs them. In on-demand paging only, no pages are initially loaded into memory when the program starts, and all pages are initially marked as being on disk....

Working Process of Demand Paging

So, let us understand this with the help of an example. Suppose we want to run a process P which have four pages P0, P1, P2, and P3. Currently, in the page table, we have pages P1 and P3....

Advantages of Demand Paging

So in the Demand Paging technique, there are some benefits that provide efficiency of the operating system....

Disadvantages of Demand Paging

Page Fault Overload: The process of swapping pages between memory and disk can cause a performance overhead, especially if the program frequently accesses pages that are not currently in memory. Degraded performance: If a program frequently accesses pages that are not currently in memory, the system spends a lot of time swapping out pages, which degrades performance. Fragmentation: Query paging can cause physical memory fragmentation, degrading system performance over time. Complexity: Implementing query paging in an operating system can be complex, requiring complex algorithms and data structures to manage page tables and swap space....

FAQs on Demand Paging

Q.1: How does demand paging differ from swapping?...