Next Fit Algorithm in Operating System (OS)

August 21, 2019

Definition

Next fit is another version of First Fit in which memory is searched for empty spaces similar to the first fit memory allocation scheme. Unlike first-fit memory allocation, the only difference between the two is, in the case of next fit, if the search is interrupted in between, the new search is carried out from the last location.

Next fit can also be said as the modified version of the first fit as it starts searching for a free memory as following the first-fit memory allocation scheme. This memory allocation scheme uses a moving pointer which moves along the empty memory slots to search memory for the next fit. The next fit memory allocation method avoids memory allocation always from the beginning of the memory space. The operating system uses a memory allocation algorithm, also known as the scheduling algorithm for this purpose.

 

Algorithm for memory allocation using Next Fit

Step 1. Enter the number of memory blocks.

Step 2. Enter the size of each memory block.

Step 3. Enter the number of processes with their sizes.

Step 4. Start by selecting each process to check if it can be assigned to the current memory block.

Step 5. If the condition in step 4 is true, then allocate the process with the required memory and check for the next process from the memory block where the searching was halted, not from the starting.

Step 6. If the current memory size is smaller, then continue to check the next blocks.

Step 7. Stop

Operating systems Memory

      Read More

  1. Memory Management Introduction
  2. Partition Allocation Method
    1. First Fit in OS
      1. Program in C | C++ | Java | Python
    2. Best fit
      1. Program in C | C++ | Java | Python
    3. Worst fit
      1. Program in C | C++ | Java | Python
    4. Next fit
      1. Program in C | C++ | Java | Python
    5. First fit best fit worst fit in OS Example
  3. Buddy- System Allocator
  4. Paging
    1. Types of Paging
  5. Fragmentation
    1. internal fragmentation
    2. external fragmentation
    3. internal fragmentation vs external fragmentation
  6. Mapping Virtual address to Physical Address.
  7. Virtual Memory 
  8. Demand Paging
  9. Implementation of Demand paging and page fault
  10. Segmentation
  11. Page Replacement Algorithms
    1. LRU
    2. FIFO
    3. Optimal Page Replacement algorithm
  12. Thrashing
  13. Belady’s Anomaly
  14. Static vs Dynamic Loading
  15. Static vs Dynamic Linking
  16. Swapping
  17. Translational Look Aside Buffer
  18. Process Address Space
  19. Difference between Segmentation and Paging
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