HSFS is a file system type that allows users access to files on High Sierra or ISO 9660 format CD-ROM
disks from within the SunOS operating system. Once mounted, a HSFS file system provides standard SunOS read-only file system operations and semantics. That is, users can
read files and list files in a directory on a High Sierra or ISO 9660 CD-ROM, and applications can use standard UNIX system calls on these
files and directories.
This file system also contains support for the Rock Ridge Extensions. If the extensions are contained on the CD-ROM, then the file system will provide all of the
file system semantics and file types of UFS, except for writability and hard links.
If your /etc/vfstab file contains a line similar to
and /hsfs exists, you can mount an HSFS file system with either of the following commands:
/dev/dsk/c0t6d0s0 -/hsfs hsfs -no ro
mount -F hsfs -o ro device-special directory-name
Normally, if Rock Ridge extensions exist on the CD-ROM, the file system will automatically use those extensions. If you do not want to use the Rock Ridge extensions,
use the ``nrr'' (No Rock Ridge) mount option. The mount command would then be:
Files on a High Sierra or ISO 9660 CD-ROM disk have names of the form filename.ext;version, where filename and the optional ext consist of a sequence of uppercase alphanumeric characters (including ``_''), while the version consists
of a sequence of digits, representing the version number of the file. HSFS converts all the uppercase characters in a file name to lowercase, and truncates the ``;'' and
version information. If more than one version of a file is present on the CD-ROM, only the file with the highest version number is accessible.
mount -F hsfs -o ro,nrr device-special directory-name
Conversion of uppercase to lowercase characters may be disabled by using the -o nomaplcase option to mount(1M). (See mount_hsfs(1M)).
If the CD-ROM contains Rock Ridge extensions, the file names and directory names may contain any character supported under UFS.
The names may also be upper and/or lower case and will be case sensitive. File name lengths can be as long as those of UFS.
Files accessed through HSFS have mode 555 (owner, group and world readable and executable), uid 0 and gid 3. If a directory on the CD-ROM
has read permission, HSFS grants execute permission to the directory, allowing it to be searched.
With Rock Ridge extensions, files and directories can have any permissions that are supported on a UFS file system; however, despite any write permissions, the file
system is read-only, with EROFS returned to any write operations.
High Sierra and ISO 9660 CD-ROMs support only regular files and directories, thus HSFS supports only these file
types. A Rock Ridge CD-ROM can support regular files, directories, and symbolic links, as well as device nodes, such as block, character, and FIFO.