/A:size Overrides the default allocation unit size. Default settings are strongly recommended for general use. NTFS supports ...

/A:size         Overrides the default allocation unit size. Default settings
                  are strongly recommended for general use.
                  NTFS supports 512, 1024, 2048, 4096, 8192, 16K, 32K, 64K.
                  FAT supports 512, 1024, 2048, 4096, 8192, 16K, 32K, 64K,
                  (128K, 256K for sector size > 512 bytes).
                  FAT32 supports 512, 1024, 2048, 4096, 8192, 16K, 32K, 64K,
                  (128K, 256K for sector size > 512 bytes).
                  exFAT supports 512, 1024, 2048, 4096, 8192, 16K, 32K, 64K,
                  128K, 256K, 512K, 1M, 2M, 4M, 8M, 16M, 32M.

                  Note that the FAT and FAT32 files systems impose the
                  following restrictions on the number of clusters on a volume:

                  FAT: Number of clusters <= 65526
                  FAT32: 65526 < Number of clusters < 4177918

                  Format will immediately stop processing if it decides that
                  the above requirements cannot be met using the specified
                  cluster size.

                  NTFS compression is not supported for allocation unit sizes
                  above 4096.

  /F:size         Specifies the size of the floppy disk to format (1.44)