File System Changes

SunOS release 5.7 and SunOS release 4 file systems are similar, but there are changes in the locations and names of system directories and files. There are also new file systems and new pseudo file systems, and one directory was removed.

Some of the changes to file system locations and names are:

• The /dev directory has changed from a flat directory to a hierarchical one.

• The /etc directory has changed and contains specific system configuration information. Several files and subdirectories have been added, removed, or changed.

• The /etc/vfstab tab file replaces /etc/fstab.

• The /etc/lp directory replaces /etc/printcap.

• The SunOS release 5.7 /sbin directory contains the rc scripts used to alter system run levels as well as the rcs script used to initialize the system prior to mounting file systems.

• The SunOS release 5.7 /usr directory contains sharable files and executables provided by the system.

• The /var directory contains files that change size during normal operation. Several files and subdirectories in the /var directory have been added, removed, or changed.

• The /var/mail directory replaces /var/spool/mail.

• The /sys directory is no longer needed because the kernel is dynamically loaded.

• The /RFS file system has been removed.

• The terminfo database replaces termcap.

Pseudo File Systems

The TFS pseudo file system is not included in the SunOS release 5.7 software.

Following are the pseudo file system systems that are included:

• CACHEFS--used to improve performance of slow devices such as CD-ROM.

• PROCFS--memory resident file system that contains a list of active processes, by process number, in the /proc directory. See the proc(4) man page.

• FDFS--lists explicit names for opening files using file descriptors.

• FIFOFS--contains pipe files that give processes common access to data.

• NAMEFS--used mostly by STREAMS for dynamic mounts of file descriptors on top of files.

• SWAPFS--provides default swap device when the system boots or you create additional swap space.

Added File Systems

The following file systems are included in the SunOS release 5.7 directory structure:

• The kernel (now called unix) and the kernel modules are stored in the /kernel directory.

• The optional /opt file system can be used to store third-party or unbundled software. If /opt is not a separate file system, it may be a symbolic link to /usr/opt.

• The /vol file system provides the default file system for the Volume Management daemon, vold(1M). See the volfs(7) man page.