SunOS 4.0 filesystem(7) man page

gistfile1.txt

Miscellaneous Information Manual                                 FILESYSTEM(7)



NAME
       filesystem - file system organization

SYNOPSIS
       /
       /usr

DESCRIPTION
       The SunOS file system tree is organized for easy administration.  Dis‐
       tinct 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 the sharable files to be
       stored on one machine, while being accessed by many  machines  using  a
       remote  file  access mechanism such as Sun's Network File System (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(8) 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
       fully functional system.  The root file system is mounted automatically
       by  the  kernel  at  boot  time; the /usr file system is mounted by the
       /etc/rc.boot script, which is run as part of the booting process.

       The root file system contains files that are unique to each machine; it
       can  not  be  shared among machines.  The root file system contains the
       following directories:

       /dev      Character and block  special  files.   Device  files  provide
                 hooks  into  hardware devices or operating system facilities.
                 The MAKEDEV(8)  command  builds  device  files  in  the  /dev
                 directory.   Typically,  device  files are built to match the
                 kernel and hardware configuration of the machine.

       /etc      Various configuration files and system administration  data‐
                 bases  that  are  machine specific.  You can think of /etc as
                 the “home directory” of a machine,  defining  its  “iden‐
                 tity.”  Executable programs are no longer kept in /etc.

       /home     Mount  points  for  home  directories.  This directory may be
                 arranged so that shared  user  files  are  placed  under  the
                 directory  /home/machine-name  on  machines  serving  as file
                 servers.  Machines may then be locally configured with  mount
                 points  under  /home for all of the file servers of interest,
                 with the name of the mount point being the name of  the  file
                 server.

       /mnt      A  generic mount point.  This is an empty directory available
                 for temporarily mounting file systems on.

       /sbin     Executable programs that  are  needed  in  the  boot  process
                 before  /usr  is mounted.  /sbin contains only those programs
                 that are needed in order  to  mount  the  /usr  file  system:
                 hostname(1),  ifconfig(8C),  init(8),  mount(8),  and  sh(1).
                 After /usr is mounted, the full complement of  utilities  are
                 available.

       /tmp      Temporary files that are deleted at reboot time.

       /var      Files,  such  as  log files, that are unique to a machine but
                 that can grow to an arbitrary (“variable”) size.

       /var/adm  System logging and accounting files.

       /var/preserve
                 Backup files for vi(1) and ex(1).

       /var/spool
                 Subdirectories for  files  used  in  printer  spooling,  mail
                 delivery, cron(8), at(1), etc.

       /var/tmp  Transitory files that are not deleted at reboot time.

       Because it is desirable to keep the root file system small, larger file
       systems are often mounted on /var and /tmp.

       The file system mounted on  /usr  contains  architecture-dependent  and
       architecture-independent   shareable  files.   The  subtree  rooted  at
       /usr/share contains architecture-independent shareable 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 architec‐
       ture  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 to prevent their accidentally modifying
       any shared files.  The /usr file system contains the following  subdi‐
       rectories:

       /usr/5bin                System V executables.

       /usr/5include            System V include files.

       /usr/5lib                System V library files.

       /usr/bin                 Executable  programs.   The bulk of the system
                                utilities are located here.

       /usr/dict                Dictionary databases.

       /usr/etc                 Executable system administration programs.

       /usr/games               Executable game programs and data.

       /usr/include             Include files.

       /usr/lib                 Program libraries  and  various  architecture-
                                dependent databases.

       /usr/pub                 Various data files.

       /usr/ucb                 Executable programs descended from the Berke‐
                                ley Software Distribution.

       /usr/share               Subtree for architecture-independent shareable
                                files.

       /usr/share/man           Subdirectories for the on-line reference man‐
                                ual pages.

       /usr/share/lib           Architecture-independent databases.

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

       /export                  The 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 SunOS release-name.

       /export/share            The exported common /usr/share directory tree.

       /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.

       /export/dump/hostname    The exported dump file for hostname.

       /export/crash/hostname   The  exported  crash dump directory for host‐
                                name.

   Changes from Previous Releases
       The file system layout described here is quite a bit different from the
       layout  employed  previous  to release 4.0 of SunOS.  For compatibility
       with earlier releases of SunOS, and other versions of the UNIX  system,
       symbolic  links  are provided for various files and directories linking
       their previous names to their current locations.   The  symbolic  links
       provided include:

       /bin —> /usr/bin        All  programs  previously  located in /bin are
                                now in /usr/bin.

       /lib —> /usr/lib        All files previously located in /lib  are  now
                                in /usr/lib.

       /usr/adm —> /var/adm    The  entire  /usr/adm directory has been moved
                                to /var/adm.

       /usr/spool —> /var/spool
                                The entire /usr/spool directory has been moved
                                to /var/spool.

       /usr/tmp —> /var/tmp    The  /usr/tmp  directory  has  been  moved  to
                                /var/tmp.

       /etc/termcap —> /usr/share/lib/termcap

       /usr/5lib/terminfo —> /usr/share/lib/terminfo

       /usr/lib/me —> /usr/share/lib/me

       /usr/lib/ms —> /usr/share/lib/ms

       /usr/lib/tmac —> /usr/share/lib/tmac

       /usr/man —> /usr/share/man

       The following program binaries have been moved from  /etc  to  /usr/etc
       with  symbolic  links  to  them  left  in /etc: arp, clri, cron, chown,
       chroot, config, dkinfo, dmesg, dump, fastboot,  fasthalt,  fsck,  halt,
       ifconfig,  link,  mkfs,  mknod,  mount,  ncheck,  newfs,  pstat, rdump,
       reboot, renice,  restore,  rmt,  rrestore,  shutdown,  umount,  update,
       unlink, and vipw.

       In  addition,  some files and directories have been moved with no sym‐
       bolic link left behind in the old location:

              Old Name            New Name

              /etc/biod           /usr/etc/biod

              /etc/fsirand        /usr/etc/fsirand

              /etc/getty          /usr/etc/getty

              /etc/in.rlogind     /usr/etc/in.rlogind

              /etc/in.routed      /usr/etc/in.routed

              /etc/in.rshd        /usr/etc/in.rshd

              /etc/inetd          /usr/etc/inetd

              /etc/init           /usr/etc/init

              /etc/nfsd           /usr/etc/nfsd

              /etc/portmap        /usr/etc/portmap

              /etc/rpc.lockd      /usr/etc/rpc.lockd

              /etc/rpc.statd      /usr/etc/rpc.statd

              /etc/ypbind         /usr/etc/ypbind

              /usr/lib/sendmail.cf
                                  /etc/sendmail.cf

              /usr/preserve       /var/preserve

              /usr/lib/aliases    /etc/aliases

              /stand              /usr/stand

              /etc/yp             /var/yp

       Note: with this new file system organization, the approach to repairing
       a  broken  file  system  changes.   One must mount /usr before doing an
       fsck(8), for example.  If the mount point for /usr has been  destroyed,
       /usr  can  be  mounted  temporarily  on /mnt or /tmp.  If the root file
       system on a standalone system is so badly damaged that  none  of  these
       mount  points exist, or if /sbin/mount has been corrupted, the only way
       to repair it may be to re-install the root file system.

SEE ALSO
       at(1), ex(1), hostname(1), sh(1), vi(1),  intro(4),  nfs(4P),  hier(7),
       ifconfig(8C), init(8), MAKEDEV(8), mount(8), fsck(8), rc(8)



                                10 January 1988                  FILESYSTEM(7)