Disk-based file systems are stored on physical media such as hard disks, CD-ROMs, and diskettes. Disk-based file systems can be written in different formats. The available formats are:
UFS - UNIX file system (based on the BSD Fast File system that was provided in the 4.3 Tahoe release). UFS is the default disk-based file system in Solaris system software.
HSFS - High Sierra and ISO 9660 file system. High Sierra is the first CD-ROM file system; ISO 9660 is the official standard version of the High Sierra File System. The HSFS file system is used on CD-ROM, and is a read-only file system. Solaris HSFS supports Rock Ridge extensions to ISO 9660, which, when present on a CD-ROM, provide all UFS file system semantics and file types except for writability and hard links.
PCFS - PC file system, which allows read/write access to data and programs on DOS-formatted disks written for DOS-based personal computers.
Each type of disk-based file system is customarily associated with a particular media device:
UFS with hard disk
HSFS with CD-ROM
PCFS with diskette
These associations are not, however, restrictive. For example, CD-ROMs and diskettes can have UFS file systems put on them.