WBJECA 2025 — Computer PYQ

Correct Option: (A) Paging suffers from internal fragmentation but not external fragmentation.

Explanation

In operating systems, paging is a memory management scheme that eliminates the need for contiguous allocation of physical memory.

• Internal Fragmentation: This occurs when the memory allocated to a process is slightly larger than the memory requested. In paging, if a process size is not an exact multiple of the page size, the last page allocated will not be completely filled. This wastage is calculated as:

  $$Internal\_Fragmentation=Page\_Size-(Process\_Size(\mathrm{mod}Page\_Size))$$

  Since the last page of a process may have unused space, paging suffers from internal fragmentation.

• External Fragmentation: This occurs when there is enough total memory space to satisfy a request, but the available space is not contiguous. Paging eliminates external fragmentation because any free frame can be allocated to any page of a process, meaning physical memory does not need to be contiguous:

  $$Total\_Free\_Memory=\sum Free\_Frames$$

  Because the operating system can map any logical page to any available physical frame, external fragmentation is effectively resolved.