First In First Out (FIFO) , fifo page replacement example, first in first out page replacement operating systems, fifo page replacement algorithm

First In First Out (FIFO) , fifo page replacement example, first in first out page replacement operating systems, fifo page replacement algorithm

 

This is the simplest page replacement algorithm. In this algorithm, the operating system keeps track of all pages in the memory in a queue, the oldest page is in the front of the queue. When a page needs to be replaced page in the front of the queue is selected for removal.

Example : Consider page reference string 1, 3, 0, 3, 5, 6, 3 with 3 page frames.Find the number of page faults.
Initially, all slots are empty, so when 1, 3, 0 come they are allocated to the empty slots —> 3 Page Faults.

when 3 comes, it is already in memory so —> 0 Page Faults. Then 5 comes, it is not available in memory so it replaces the oldest page slot i.e 1. —>1 Page Fault. 6 comes, it is also not available in memory so it replaces the oldest page slot i.e 3 —>1 Page Fault. Finally, when 3 comes it is not available so it replaces 0 1 page fault.

Belady’s anomaly proves that it is possible to have more page

faults when increasing the number of page frames while using the First in First Out (FIFO) page replacement algorithm. For example, if we consider reference

strings 3, 2, 1, 0, 3, 2, 4, 3, 2, 1, 0, 4, and 3 slots, we get 9 total page faults, but if we increase slots to 4, we get 10-page faults.

 

 

---

 

Topics Covered :

• what is operating system and its types
• operating system in computer
• operating system responsibilities
• operating system definition
• operating system kya hai
• operating system in hindi
• operating system pdf
• operating system ppt
• operating system full course
• types of operating system
• functions of operating system
• operating system in detail
• what is operating system full information
• use of operating system
• operating system
• why operating system
• what is operating system

---

 

 

---