Disk-Based File Systems (System Administration Guide: Devices and File Systems)

System Administration Guide: Devices and File Systems

Disk-Based File Systems

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 described in the following table.

Disk-Based File System	Format Description
UFS	UNIX file system (based on the BSD Fat Fast File system that was provided in the 4.3 Tahoe release). UFS is the default disk-based file system for the Solaris OS. Before you can create a UFS file system on a disk, you must format the disk and divide it into slices. For information on formatting disks and dividing disks into slices, see Chapter 10, Managing Disks (Overview).
ZFS	The ZFS file system is new in the Solaris Express release. For more information, see the Solaris ZFS Administration Guide.
HSFS	High Sierra, Rock Ridge, 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-ROMs, and is a read-only file system. Solaris HSFS supports Rock Ridge extensions to ISO 9660. When present on a CD-ROM, these extensions provide all UFS file system features and file types, except for writability and hard links.
PCFS	PC file system, which allows read- and write- access to data and programs on DOS-formatted disks that are written for DOS-based personal computers.
UDFS	The Universal Disk Format (UDFS) file system, the industry-standard format for storing information on the optical media technology called DVD (Digital Versatile Disc or Digital Video Disc).

Each type of disk-based file system is customarily associated with a particular media device, as follows:

UFS with hard disk
HSFS with CD-ROM
PCFS with diskette
UDF with DVD

However, these associations are not restrictive. For example, CD-ROMs and diskettes can have UFS file systems created on them.

The Universal Disk Format (UDFS) File System

For information about creating a UDFS file system on removable media, see How to Create a File System on Removable Media.

The UDF file system is the industry-standard format for storing information on DVD (Digital Versatile Disc or Digital Video Disc) optical media.

The UDF file system is provided as dynamically loadable 32-bit and 64-bit modules, with system administration utilities for creating, mounting, and checking the file system on both SPARC and x86 platforms. The Solaris UDF file system works with supported ATAPI and SCSI DVD drives, CD-ROM devices, and disk and diskette drives. In addition, the Solaris UDF file system is fully compliant with the UDF 1.50 specification.

The UDF file system provides the following features:

Ability to access the industry-standard CD-ROM and DVD-ROM media when they contain a UDF file system
Flexibility in exchanging information across platforms and operating systems
A mechanism for implementing new applications rich in broadcast-quality video, high-quality sound, and interactivity using the DVD video specification based on UDF format

The following features are not included in the UDF file system:

Support for write-once media, (CD-RW), with either the sequential disk-at-once recording and incremental recording
UFS components such as quotas, ACLs, transaction logging, file system locking, and file system threads, which are not part of the UDF 1.50 specification

The UDF file system requires the following:

At least the Solaris 7 11/99 release
Supported SPARC or x86 platform
Supported CD-ROM or DVD-ROM device

The Solaris UDF file system implementation provides the following:

Support for industry-standard read/write UDF version 1.50
Fully internationalized file system utilities