Man page or keyword search:   man All Sections 1 - General Commands 2 - System Calls 3 - Subroutines, Functions 4 - Special Files 5 - File Formats 6 - Games and Screensavers 7 - Macros and Conventions 8 - Maintenence Commands 9 - Kernel Interface New Commands Server 4.4BSD AIX Alpinelinux Archlinux Aros BSDOS BSDi Bifrost CentOS Cygwin Darwin Debian DigitalUNIX DragonFly ElementaryOS Fedora FreeBSD Gentoo GhostBSD HP-UX Haiku Hurd IRIX Inferno JazzOS Kali Knoppix LinuxMint MacOSX Mageia Mandriva Manjaro Minix MirBSD NeXTSTEP NetBSD OPENSTEP OSF1 OpenBSD OpenDarwin OpenIndiana OpenMandriva OpenServer OpenSuSE OpenVMS Oracle PC-BSD Peanut Pidora Plan9 QNX Raspbian RedHat Scientific Slackware SmartOS Solaris SuSE SunOS Syllable Tru64 UNIXv7 Ubuntu Ultrix UnixWare Xenix YellowDog aLinux   9747 pages apropos Keyword Search (all sections) Output format html ascii pdf view pdf save postscript

NVRAM(4)		 BSD Kernel Interfaces Manual		      NVRAM(4)

NAME
     nvram — non-volatile RAM

SYNOPSIS
     To compile this driver into the kernel, place the following line in your
     kernel configuration file:

	   device nvram

     Alternatively, to load the driver as a module at boot time, place the
     following line in loader.conf(5):

	   nvram_load="YES"

DESCRIPTION
     The nvram driver provides access to BIOS configuration NVRAM on i386 and
     amd64 systems.

     PC motherboard uses a small non-volatile memory to store BIOS settings
     which is usually part of its clock chip and sometimes referred as “CMOS
     SRAM”.  This driver exposes bytes 14 through 128 of the NVRAM, or a total
     of 114 bytes, at offset zero of the device file /dev/nvram.

     This driver is useful for cloning machines that shares the same hardware
     configuration and need same BIOS setting tweaks.

IMPLEMENTATION NOTES
     The BIOS NVRAM's bytes 16 through 31 are checksummed at byte 32.  This
     driver does not take care for these checksums.

EXAMPLES
     Backup existing BIOS NVRAM to nvram.bin:

	   dd if=/dev/nvram of=nvram.bin

     Restore BIOS NVRAM from nvram.bin:

	   dd if=nvram.bin of=/dev/nvram

SEE ALSO
     dd(1)

HISTORY
     The nvram device driver first appeared in FreeBSD 6.4.

AUTHORS
     The nvram device driver was written by Peter Wemm.	 This manual page was
     written by Xin LI.

BSD			       February 8, 2010				   BSD

Vote for polarhome