The HPFS was designed by IBM/Microsoft for IBMs new windowing system, OS/2. It was designed to be fast, remove all the shortcomings of FAT, support long filenames, small cluster sizes, remove fragmentation as much as possible and support more attributes.
About HPFS (High Performace Filesystem)
HPFS is the precursor to NTFS and is, in a nutshell, NTFS minus the security features embeded into NTFS. Instead of storing cluster chains in a single linked list format, HPFS stores its information in sorted B-Tree's. This makes searching for files very fast.
Instead of keeping the directory tables and other descriptors at the start of the disk, HPFS bands them at regular intervals throughout the disk and in the middle of the disk, with the theory being that the heads only have to move half as much in any direction.
More information about HPFS can be found at: http://web.archive.org/web/20120204050411/http://www.nondot.org/sabre/os/files/FileSystems/HPFS/