but as larger-capacity drives became available, it meant that the smallest amount of space that any file could occupy (a single allocation block) became excessively large, wasting significant amounts of space. For example, on a 1 GB disk, the allocation block size under HFS is 16 KB, so even a 1-byte file would take up 16 KB of disk space. HFS Plus's system greatly improves space utilization on larger disks as a result. File and folder names in HFS Plus are also encoded in UTF-16 and normalized to a form very nearly the same as Unicode Normalization Form D (NFD) (which means that precomposed characters like "å" are decomposed in the HFS+ filename and therefore count as two code units and UTF-16 implies that characters from outside the Basic Multilingual Plane also count as two code units in an HFS+ filename). HFS Plus permits filenames up to 255 UTF-16 code units in length. Formerly, HFS Plus volumes were embedded inside an HFS standard file system. This was phased out by the Tiger transition to Intel Macs, where the HFS Plus file system was not embedded inside a wrapper. The wrapper had been designed for two purposes; it allowed Macintosh computers without HFS Plus support in their ROM to boot HFS Plus volumes and it also was designed to help users transition to HFS Plus by including a minimal HFS volume with a read-only file called Where_have_all_my_files_gone?, explaining to users with versions of Mac OS 8.0 and earlier without HFS Plus, that the volume requires a system with HFS Plus support. The original HFS volume contains a signature and an offset to the embedded HFS Plus volume within its volume header. All allocation blocks in the HFS volume which contain the embedded volume are mapped out of the HFS allocation file as bad blocks. Notable among file systems used for Unix systems, HFS Plus does not support sparse files. There are nine structures that make up a typical HFS Plus volume: Sectors 0 and 1 of the volume are HFS boot blocks. These are identical to the boot blocks in an HFS volume. They are part of the HFS wrapper. Sector 2 contains the Volume Header, which is equivalent to the Master Directory Block in an HFS volume. The Volume Header stores a wide variety of data about the volume itself, for example the size of allocation blocks, a timestamp that