.\" $OpenBSD: mount_kernfs.8,v 1.23 2005/04/28 17:32:35 biorn Exp $ .\" $NetBSD: mount_kernfs.8,v 1.6 1995/03/18 14:57:24 cgd Exp $ .\" .\" Copyright (c) 1992, 1993, 1994 .\" The Regents of the University of California. All rights reserved. .\" All rights reserved. .\" .\" This code is derived from software donated to Berkeley by .\" Jan-Simon Pendry. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)mount_kernfs.8 8.2 (Berkeley) 3/27/94 .\" .Dd March 27, 1994 .Dt MOUNT_KERNFS 8 .Os .Sh NAME .Nm mount_kernfs .Nd mount the /kern file system .Sh SYNOPSIS .Nm mount_kernfs .Op Fl o Ar options .Ar /kern .Ar mount_point .Sh DESCRIPTION The .Nm command attaches an instance of the kernel parameter namespace to the global filesystem namespace. The conventional mount point is .Pa /kern . This command is invoked by .Xr mount 8 when using the syntax .Bd -ragged -offset 4n .Nm mount Op options -t kernfs .Ar /kern .Ar mount_point .Ed .Pp This command is normally executed by .Xr mount 8 at boot time. .Pp The filesystem includes several regular files which can be read, some of which can also be written. The contents of the files are in a machine-independent format, either a string, or an integer in decimal ASCII. Where numbers are returned, a trailing newline character is also added. .Pp The options are as follows: .Bl -tag -width Ds .It Fl o Ar options Options are specified with a .Fl o flag followed by a comma separated string of options. See the .Xr mount 8 man page for possible options and their meanings. .El .Pp Statistics reported by .Xr df 1 on the .Pa /kern filesystem will indicate the amount of unwired/physical memory instead of .Sq disk space , and the number of vnodes used/allocated instead of .Sq inodes . The filesystem's block size is the system's page size. .Sh FILES .Bl -tag -width domainname -compact .It Pa boottime Time at which the system was last booted (decimal ASCII). .It Pa byteorder _BYTE_ORDER for this kernel. .It Pa copyright Kernel copyright message. .It Pa domainname The domainname, with a trailing newline. Behaves like a hostname. .It Pa hostname The hostname, with a trailing newline. The hostname can be changed by writing to this file. A trailing newline will be stripped from the hostname being written. .It Pa hz Frequency of the system clock (decimal ASCII). .It Pa ipsec The currently configured IPsec Security Associations. .It Pa loadavg The 1, 5 and 15 minute load average in kernel fixed-point format. The final integer is the fix-point scaling factor. All numbers are in decimal ASCII. .It Pa machine Architecture this kernel was compiled for. .It Pa model Model of the processor this machine is running on. .It Pa msgbuf Kernel message buffer, also read by .Xr syslogd 8 , through the .Pa log device, and by .Xr dmesg 8 . .It Pa ncpu Number of CPUs in this machine. .It Pa osrelease OS release number. .It Pa osrev OS revision number (BSD from .Aq Pa sys/param.h ) . .It Pa ostype OS type for this kernel ("OpenBSD"). .It Pa pagesize Machine pagesize (decimal ASCII). .It Pa physmem Number of pages of physical memory in the machine (decimal ASCII). .\" .It Pa root .\" the system root directory. .\" In a chroot'ed environment, .\" .Nm .\" can be used to create a new .\" .Pa /kern .\" mount point. .\" .Pa /kern/root .\" will then refer to the system global root, not the current process root. .It Pa posix _POSIX_VERSION for this kernel. .It Pa rootdev Root device. .It Pa rrootdev Raw root device. .It Pa time Second and microsecond value of the system clock. Both numbers are in decimal ASCII. .It Pa usermem Number of pages of physical memory available for user processes. .It Pa version Kernel version string. The head line for .Pa /etc/motd can be generated by running: .Dq Ic "sed 1q /kern/version" . .El .Sh SEE ALSO .Xr mount 2 , .Xr fstab 5 , .Xr dmesg 8 , .Xr mount 8 , .Xr syslogd 8 , .Xr umount 8 .Sh HISTORY The .Nm utility first appeared in .Bx 4.4 . .Sh CAVEATS This filesystem may not be NFS-exported. .Pp Due to non-atomic operations and the potential for race conditions, programs should not depend on information obtained from this filesystem.