1.\" 2.\"Copyright (c) 2010 iXsystems, Inc. 3.\"All rights reserved. 4.\" written by: Xin LI <delphij@FreeBSD.org> 5.\" 6.\"Redistribution and use in source and binary forms, with or without 7.\"modification, are permitted provided that the following conditions 8.\"are met: 9.\"1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\"2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\"THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\"ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\"IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\"ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\"FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\"DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\"OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\"HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\"LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\"OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\"SUCH DAMAGE. 26.\" 27.Dd February 8, 2010 28.Dt NVRAM 4 29.Os 30.Sh NAME 31.Nm nvram 32.Nd "non-volatile RAM" 33.Sh SYNOPSIS 34To compile this driver into the kernel, 35place the following line in your 36kernel configuration file: 37.Bd -ragged -offset indent 38.Cd "device nvram" 39.Ed 40.Pp 41Alternatively, to load the driver as a 42module at boot time, place the following line in 43.Xr loader.conf 5 : 44.Bd -literal -offset indent 45nvram_load="YES" 46.Ed 47.Sh DESCRIPTION 48The 49.Nm 50driver provides access to BIOS configuration NVRAM on i386 and amd64 51systems. 52.Pp 53PC motherboard uses a small non-volatile memory to store BIOS settings 54which is usually part of its clock chip and sometimes referred as 55.Dq CMOS SRAM . 56This driver exposes bytes 14 through 128 of the NVRAM, or a total of 57114 bytes, at offset zero of the device file 58.Pa /dev/nvram . 59.Pp 60This driver is useful for cloning machines that shares the same hardware 61configuration and need same BIOS setting tweaks. 62.Sh IMPLEMENTATION NOTES 63The BIOS NVRAM's bytes 16 through 31 are checksummed at byte 32. 64This driver 65.Em does not 66take care for these checksums. 67.Sh EXAMPLES 68Backup existing BIOS NVRAM to 69.Pa nvram.bin : 70.Pp 71.Dl dd if=/dev/nvram of=nvram.bin 72.Pp 73Restore BIOS NVRAM from 74.Pa nvram.bin : 75.Pp 76.Dl dd if=nvram.bin of=/dev/nvram 77.Sh SEE ALSO 78.Xr dd 1 79.Sh HISTORY 80The 81.Nm 82device driver first appeared in 83.Fx 6.4 . 84.Sh AUTHORS 85.An -nosplit 86The 87.Nm 88device driver was written by 89.An Peter Wemm . 90This manual page was written by 91.An Xin LI . 92