The Workplace Shell introduces several new reasons for choosing the High Performance File System (HPFS) instead of the File Allocation Table (FAT) format for your most heavily used disks and partitions. The main ones are:
Performance
Although the FAT file system is much faster in OS/2 V2.0 than it was in OS/2 Version 1.3, there are still areas where HPFS is faster. One major advantage is the reduction of disk fragmentation, discussed below. Another is the performance when reading large files; the "EA_DATA. SF" file on a FAT file system can exceed 600 KB, which could impair the performance of instantiating WPFileSystem objects.
Fragmentation
Since the WPS encourages users to move files around and create new folders (directories), the file system is more heavily used than it would be under DOS. Past experiences with heavily used DOS workstations and LAN Servers leads us to feel there is a distinct possibility that fragmentation will cause performance problems on FAT-based disks.
Use of Extended Attributes
Since Extended Attributes (EAs) are used extensively by all directories and files within the desktop structure, there are important considerations for file transfer between the different file systems. These EAs store settings information, such as file type, without which the system cannot function properly. In general, we recommend installing a common file system on all machines to prevent potential problems with lost EAs. EAs are discussed more fully in Extended Attributes and Extended Attributes.
Long Filenames
The WPS allows a user to rename a file by editing the icon description. On HPFS, this name will be stored as it is typed, including spaces. On FAT, however, the name is truncated by removing vowels. Not only might this cause problems with duplicate filenames, it also introduces an inconsistency between what the user sees in a folder and in drives which would not otherwise occur with HPFS.
Support for Multiple Operating Systems
Multiple operating systems may be required by some users. This would lead to the user installing different file systems on the various partitions to support the different operating systems. For example, a user might need to be able to boot from DOS occasionally, to run programs that don't work in a VDM. To do this he could format the C: partition as HPFS, for OS/2 V2.0, and the D: partition as FAT, for DOS.