OS/2 FAQ List: User's Edition (4 Apr 94)

(1.5) High Performance File System (HPFS)

Why should I use HPFS?  What does it offer me?  Does it work with DOS?

HPFS is an installable file system (IFS) provided with OS/2 which may 
optionally be used instead of (or alongside) the standard DOS-style FAT 
(File Allocation Table) file system.  HPFS offers long file names (up to 
254 characters including the path, greatly exceeding the "8 dot 3" limit 
in DOS's FAT file system), contiguous storage of extended attributes 
(without the EA DATA. SF file used by FAT), resistance to file 
fragmentation, improved media error handling, smaller cluster size, 
support for larger file storage devices (up to 512 GB), and speedier disk 
operation, particularly on large hard disks, on systems with more than 6 
MB of RAM.  HPFS is not case sensitive, although it does preserve case in 
file names.

However, HPFS is not currently supported on removeable media, although 
some programs (e.g. BACKUP) preserve long file names on such FAT disks. 
 Also, native mode DOS cannot access a HPFS partition {{ (without a 
special utility). }}  However, DOS/Windows sessions running under OS/2 can 
use all files that conform to the "8 dot 3" naming conventions, even if 
they are stored on HPFS volumes.  (FAT is not required for compatibility 
with DOS and Windows applications.)

Related information:

(3.4) Disk Utilities 
(4.3) Hard Disk Partitioning 
(4.4) Starting OS/2 from Diskette

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