How to Format a Hard Drive Using Disk Utility

Depending on the file system, there are different ways to format your hard drive. When a hard drive is formatted, it determines the partitioning scheme and how data is stored on the disc.

The most common file systems are NTFS and FAT32, both of which are supported by Windows 10. The simplest way to format a hard drive is using the Disk Utility program built into the operating system. It shows all internal and external drives/partitions in a sidebar, which makes it easy to select the correct one.

FAT is a file system that was widely used on floppy disks during the MS-DOS and Windows 9x eras. It is a low-level, single-partition file system that uses small clusters for files that exceed one sector in size, making it less susceptible to the fragmentation that plagues higher-level file systems such as NTFS.

Each cluster is identified by a number (from 12 to 32) that corresponds to the bits of a FAT entry. File size information is stored in the cluster chain, and the FAT entries are read and interpreted by the operating system. The OS traverses the file system, looking up the cluster numbers of each part of a file, until the end of the file is reached.

Later, Microsoft introduced a variant of FAT called FAT16B that increased the maximum file size to 4 Gb and reduced the amount of space needed for each cluster. However, it was not compatible with FAT12 or earlier versions of the OS and could lead to inconsistencies when sharing files between systems that use different variants of the file system.