148225Sbostic.\" Copyright (c) 1991 The Regents of the University of California. 248225Sbostic.\" All rights reserved. 347676Scael.\" 4*48960Scael.\" %sccs.include.redist.roff% 547676Scael.\" 6*48960Scael.\" @(#)mem.4 5.3 (Berkeley) 05/02/91 748225Sbostic.\" 8*48960Scael.Dd 9*48960Scael.Dt MEM 4 i386 10*48960Scael.Os 11*48960Scael.Sh NAME 12*48960Scael.Nm mem , 13*48960Scael.Nm kmem 14*48960Scael.Nd memory files 15*48960Scael.Sh DESCRIPTION 16*48960ScaelThe special file 17*48960Scael.Nm /dev/mem 18*48960Scaelis an interface to the physical memory of the computer. 19*48960ScaelByte offsets in this file are interpreted as physical memory addresses. 20*48960ScaelReading and writing this file is equivalent to reading and writing 21*48960Scaelmemory itself. 22*48960ScaelOnly offsets within the bounds of 23*48960Scael.Nm /dev/mem 24*48960Scaelare allowed. 25*48960Scael.Pp 26*48960ScaelKernel virtual memory is accessed through the interface 27*48960Scael.Nm /dev/kmem 28*48960Scaelin the same manner as 29*48960Scael.Nm /dev/mem . 30*48960ScaelOnly kernel virtual addresses that are currently mapped to memory are allowed. 31*48960Scael.Pp 32*48960ScaelOn 33*48960Scael.Tn ISA 34*48960Scaelthe 35*48960Scael.Tn I/O 36*48960Scaelmemory space begins at physical address 0x000a0000 3747676Scaeland runs to 0x00100000. 38*48960ScaelThe 39*48960Scaelper-process data 40*48960Scaelsize 41*48960Scaelfor the current process 42*48960Scaelis 43*48960Scael.Dv UPAGES 44*48960Scaellong, and ends at virtual 4547676Scaeladdress 0xfe000000. 46*48960Scael.Sh FILES 47*48960Scael.Bl -tag -width Pa -compact 48*48960Scael.It Pa /dev/mem 49*48960Scael.It Pa /dev/kmem 50*48960Scael.El 51*48960Scael.Sh HISTORY 52*48960ScaelThe 53*48960Scael.Nm mem , 54*48960Scael.Nm kmem 55*48960Scaelfiles appeared in 56*48960Scael.At v6 . 57