1.\" $OpenBSD: nvram.4,v 1.4 2007/05/31 19:19:55 jmc Exp $ 2.\" 3.\" Copyright 2004 Joshua Stein <jcs@openbsd.org> 4.\" All rights reserved. 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 ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.Dd $Mdocdate: May 31 2007 $ 27.Dt NVRAM 4 i386 28.Os 29.Sh NAME 30.Nm nvram 31.Nd driver for reading PC NVRAM contents 32.Sh SYNOPSIS 33.Cd "pseudo-device nvram 1" 34.Sh DESCRIPTION 35The 36.Nm 37device provides read-only access to the non-volatile memory contained in the 38MC146818 real-time clock. 39.Pp 40This data is provided as a seekable character device, 41.Pa /dev/nvram . 42Checksums of the NVRAM contents are calculated over bytes 2 to 31 and stored 43in byte 32. 44A valid checksum is required for the driver to initialize. 45.Sh FILES 46.Bl -tag -width /dev/nvram 47.It Pa /dev/nvram 48.El 49.Sh HISTORY 50.Nm 51support was originally included in 52.Ox 3.7 . 53