On a 4 GB hard drive, a file containing 4 KB of information would require 64 KB of space with HFS. With HFS+, it would only require 4 KB on the 4 GB hard drive. This is because the HFS allocation block size would be 16 KB and HFS+'s increased number of allocation blocks of the disk and the decreased minimum size of the blocks allows for less wasted space.
HFS+ also supports much larger files than HFS, with 32-bit block addresses as opposed to HFS's 16-bit length.
It uses Unicode to name files, encoded in UTF-16 and normalized to a form similar to Unicode Normalization Form D (NFD).
HFS+ permits file names of up to 255 UTF-16 characters in length and n-forked files. HFS+ uses a 32-bit allocation mapping table, as opposed to HFS's 16-bit table. Also, unlike most other file systems; HFS+ supports hard links to directories. HFS+ uses B-trees to store most volume metadata.