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Name

filesystem - file system organization

Synopsis


/
/usr
/export

Description

The file system tree is organized for administrative convenience. Distinct areas within the file system tree are provided for files that are private to one machine, files that can be shared by multiple machines of a common architecture, files that can be shared by all machines, and home directories. This organization allows sharable files to be stored on one machine but accessed by many machines using a remote file access mechanism such as NFS. Grouping together similar files makes the file system tree easier to upgrade and manage.

The file system tree consists of a root file system and a collection of mountable file systems. The mount(2) program attaches mountable file systems to the file system tree at mount points (directory entries) in the root file system or other previously mounted file systems. Two file systems, / (the root) and /usr, must be mounted in order to have a completely functional system. The root file system is mounted automatically by the kernel at boot time; the /usr file system is mounted by the system start-up script, which is run as part of the booting process.

Root File System

The root file system contains files that are unique to each machine. It contains the following directories:

/dev
Primary location for special files. Typically, device files are built to match the kernel and hardware configuration of the machine.
/dev/dsk
Block disk devices.
/dev/pts
Pseudo-terminal devices.
/dev/rdsk
Raw disk devices.
/dev/rmt
Raw tape devices.
/dev/sad
Entry points for the STREAMS Administrative driver.
/dev/term
Terminal devices.
/etc
Host-specific administrative configuration files and databases. /etc may be viewed as the directory that defines the machine’s identity.
/etc/acct
Accounting system configuration information.
/etc/cron.d
Configuration information for cron(1M) .
/etc/default
Defaults information for various programs.
/etc/dfs
Configuration information for exported file systems.
/etc/fs
Binaries organized by file system types for operations required before /usr is mounted.
/etc/inet
Configuration files for Internet services.
/etc/init.d
Shell scripts for transitioning between run levels.
/etc/lib
Shared libraries needed during booting.
/etc/lp
Configuration information for the printer subsystem.
/etc/mail
Mail subsystem configuration.
/etc/net
Configuration information for transport independent network services.
/etc/opt
Configuration information for optional packages.
/etc/rc0.d
Scripts for entering or leaving run level 0. See init(1M) .
/etc/rc1.d
Scripts for entering or leaving run level 1. See init(1M) .
/etc/rc2.d
Scripts for entering or leaving run level 2. See init(1M) .
/etc/rc3.d
Scripts for entering or leaving run level 3. See init(1M) .
/etc/saf
Service Access Facility files.
/etc/skel
Default profile scripts for new user accounts. See useradd(1M) .
/etc/sm
Status monitor information.
/etc/sm.bak
Backup status monitor information.
/etc/tm
Trademark files; contents displayed at boot time.
/etc/uucp
UUCP configuration information. See uucp(1C) .
/export
Default root of the exported file system tree.
/home
Default root of a subtree for user directories.
/kernel
Subtree of Platform Independent loadable kernel modules required as part of the boot process. It includes the generic part of the core kernel that is platform-independent, /kernel/genunix. See kernel(1M) .
/mnt
Default temporary mount point for file systems. This is an empty directory on which file systems may be temporarily mounted.
/opt
Root of a subtree for add-on application packages.
/platform
Subtree of Platform Specific objects which need to reside on the root filesystem. It contains a series of directories, one per supported platform. The semantics of the series of directories is equivalent to / (root).
/platform/*/kernel
Platform Dependent objects with semantics equivalent to /kernel. It includes the file unix ,the core kernel that is platform dependent. See kernel(1M) .
/platform/*/lib
Platform Dependent objects with semantics equivalent to /lib.
/platform/*/sbin
Platform Dependent objects with semantics equivalent to /sbin.
/proc
Root of a subtree for the process file system.
/sbin
Essential executables used in the booting process and in manual system recovery. The full complement of utilities is available only after /usr is mounted.
/tmp
Temporary files; cleared during the boot operation.
/var
Root of a subtree for varying files. Varying files are files that are unique to a machine but that can grow to an arbitrary (that is, variable) size. An example is a log file.
/var/adm
System logging and accounting files.
/var/cron
Log files for cron(1M) .
/var/mail
Directory where users’ mail is kept.
/var/news
Community service messages. Note: this is not the same as USENET-style news.
/var/nis
NIS+ databases.
/var/opt
Root of a subtree for varying files associated with optional software packages.
/var/preserve
Backup files for vi(1) and ex(1) .
/var/sadm
Databases maintained by the software package management utilities.
/var/saf
Service access facility logging and accounting files.
/var/spool
Root directory for files used in printer spooling, mail delivery, cron(1M) , at(1) , etc.
/var/spool/cron
cron(1M) and at(1) spooling files.
/var/spool/locks
Spooling lock files.
/var/spool/lp
Line printer spool files. See lp(1) .
/var/spool/mqueue
Mail queued for delivery.
/var/spool/pkg
Spooled packages.
/var/spool/uucp
Queued uucp(1C) jobs.
/var/spool/uucppublic
Files deposited by uucp(1C) .
/var/tmp
Transitory files; this directory is not cleared during the boot operation.
/var/uucp
uucp(1C) log and status files.
/var/yp
Databases needed for backwards compatibility with NIS and ypbind(1M) ; unnecessary after full transition to NIS+.

/usr File System

Because it is desirable to keep the root file system small and not volatile, on disk-based systems larger file systems are often mounted on /home, /opt, /usr, and /var.

The file system mounted on /usr contains architecture-dependent and architecture-independent sharable files. The subtree rooted at /usr/share contains architecture-independent sharable files; the rest of the /usr tree contains architecture-dependent files. By mounting a common remote file system, a group of machines with a common architecture may share a single /usr file system. A single /usr/share file system can be shared by machines of any architecture. A machine acting as a file server may export many different /usr file systems to support several different architectures and operating system releases. Clients usually mount /usr read-only so that they do not accidentally change any shared files.

The /usr file system contains the following subdirectories:

/usr/4lib
a.out libraries for the Binary Compatibility Package. See
/usr/bin
Primary location for standard system utilities.
/usr/bin/sunview1
SunView executables. This directory is only present when the Binary Compatibility Package is installed.
/usr/ccs
C compilation system.
/usr/ccs/bin
C compilation commands and system utilities.
/usr/ccs/lib
Libraries and auxiliary files.
/usr/demo
Demo programs and data.
/usr/dt
root of a subtree for CDE Motif.
/usr/dt/bin
Primary location for CDE Motif system utilities.
/usr/dt/include
Header files for CDE Motif.
/usr/dt/lib
Libraries for CDE Motif.
/usr/dt/man
On-line reference manual pages for CDE Motif.
/usr/games
Game binaries and data.
/usr/include
Include headers (for C programs, etc).
/usr/kernel
Subtree of Platform Independent loadable kernel modules, not needed in the root filesystem.
/usr/platform
Subtree of Platform Specific objects which does not need to reside on the root filesystem. It contains a series of directories, one per supported platform. The semantics of the series of directories is equivalent to /platform, except for subdirectories which don’t provide utility under one or the other (for example: /platform/include isn’t needed).
/platform/*/include
Platform Dependent headers with semantics equivalent to /usr/include.
/platform/*/kernel
Platform Dependent objects with semantics equivalent to /usr/kernel.
/platform/*/lib
Platform Dependent objects with semantics equivalent to /usr/lib.
/platform/*/sbin
Platform Dependent objects with semantics equivalent to /usr/sbin.
/usr/lib
Program libraries, various architecture-dependent databases, and executables not invoked directly by the user (system daemons, etc).
/usr/lib/acct
Accounting scripts and binaries. See acct(1M) .
/usr/lib/dict
Database files for spell(1) .
/usr/lib/class
Scheduling class-specific directories containing executables for priocntl(1) and dispadmin(1M) .
/usr/lib/font
troff(1) font description files.
/usr/lib/fs
File system type dependent modules; generally not intended to be invoked directly by the user.
/usr/lib/iconv
Conversion tables for iconv(1) .
/usr/lib/libp
Profiled libraries.
/usr/lib/locale
Localization databases.
/usr/lib/lp
Line printer subsystem databases and back-end executables.
/usr/lib/mail
Auxiliary programs for the mail(1) subsystem.
/usr/lib/netsvc
Internet network services.
/usr/lib/nfs
Auxiliary NFS-related programs and daemons.
/usr/lib/pics
Position Independent Code (PIC) archives needed to rebuild the run-time linker.
/usr/lib/refer
Auxiliary programs for refer(1) .
/usr/lib/sa
Scripts and commands for the system activity report package. See sar(1) .
/usr/lib/saf
Auxiliary programs and daemons related to the service access facility.
/usr/lib/spell
Auxiliary programs and databases for spell(1) . This directory is only present when the Binary Compatibility Package is installed.
/usr/lib/uucp
Auxiliary programs and daemons for uucp(1C) .
/usr/local
Commands local to a site.
/usr/net/servers
Entry points for foreign name service requests relayed using the network listener. See listen(1M) .
/usr/oasys
Commands and files related to the optional Framed Access Command Environment (FACE) package. See face(1) .
/usr/old
Programs that are being phased out.
/usr/openwin
Installation or mount point for the OpenWindows software.
/usr/sadm
System administration files and directories.
/usr/sadm/bin
Binaries for the Form and Menu Language Interpreter (FMLI) scripts. See fmli(1) .
/usr/sadm/install
Executables and scripts for package management.
/usr/sbin
Executables for system administration.
/usr/sbin/static
Statically linked version of selected programs from /usr/bin and /usr/sbin. These are used to recover from broken dynamic linking and before all pieces necessary for dynamic linking are present.
/usr/share
Architecture-independent sharable files.
/usr/share/man
On-line reference manual pages (if present).
/usr/share/lib
Architecture-independent databases.
/usr/share/lib/keytables
Keyboard layout description tables.
/usr/share/lib/mailx
Help files for mailx(1) .
/usr/share/lib/nterm
nroff(1) terminal tables.
/usr/share/lib/pub
Character set data files.
/usr/share/lib/spell
Auxiliary scripts and databases for spell(1) .
/usr/share/lib/tabset
Tab setting escape sequences.
/usr/share/lib/terminfo
Terminal description files for terminfo(4) .
/usr/share/lib/tmac
Macro packages and related files for text processing tools, for example, nroff(1) and troff(1) .
/usr/share/lib/zoneinfo
Time zone information.
/usr/share/src
Source code for utilities and libraries.
/usr/snadm
SNAG files.
/usr/ucb
Berkeley compatibility package binaries. See
/usr/ucbinclude
Berkeley compatibility package headers.
/usr/ucblib
Berkeley compatibility package libraries.
/usr/vmsys
Commands and files related to the optional FACE package. See face(1) . Berkeley compatibility package libraries.

/export File System

A machine with disks may export root file systems, swap files, and /usr file systems to diskless or partially-disked machines that mount them into the standard file system hierarchy. The standard directory tree for sharing these file systems from a server is:

/export
The default root of the exported file system tree.
/export/exec/architecture-name
The exported /usr file system supporting architecture-name for the current release.
/export/exec/architecture-name.release-name
The exported /usr file system supporting architecture-name for release-name.
/export/exec/share
The exported common /usr/share directory tree.
/export/exec/share.release-name
The exported common /usr/share directory tree for release-name.
/export/root/hostname
The exported root file system for hostname.
/export/swap/hostname
The exported swap file for hostname.
/export/var/hostname
The exported /var directory tree for hostname.

See Also

at(1) , ex(1) , face(1) , fmli(1) , iconv(1) , lp(1) , mail(1) , mailx(1) , nroff(1) , priocntl(1) , refer(1) , sar(1) , sh(1) , spell(1) , troff(1) , uucp(1C) , vi(1) , acct(1M) , cron(1M) , dispadmin(1M) , fsck(1M) , init(1M) , kernel(1M) , mknod(1M) , mount(1M) , useradd(1M) , ypbind(1M) , mount(2) , intro(4) , terminfo(4)



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