Which of the following is not typically considered a major file system?

• A. FAT
• B. NTFS
• C. Ext2
• D. ISO 9660

Answer: (D)

In file system terminology, you’re looking for which option isn’t used as a primary, general-purpose storage system. FAT, NTFS, and Ext2 are all core file systems that power everyday storage on different operating systems: FAT on many removable media and older systems, NTFS as the Windows default with features like permissions and journaling, and Ext2 as a traditional Linux filesystem. ISO 9660, on the other hand, is built for optical media like CD-ROMs and is typically read-only with a constrained feature set. It’s designed to ensure interoperability of discs across systems, not to serve as a primary storage filesystem on hard drives or in typical computer environments. Because of that specialized, read-only scope, ISO 9660 is not usually considered a major filesystem in the same sense as FAT, NTFS, or Ext2.