1*61587Sbostic.\" Copyright (c) 1990, 1991, 1993 2*61587Sbostic.\" The Regents of the University of California. All rights reserved. 344666Sbostic.\" 447672Scael.\" %sccs.include.redist.man% 544666Sbostic.\" 6*61587Sbostic.\" @(#)mem.4 8.1 (Berkeley) 06/05/93 747672Scael.\" 847672Scael.Dd 947672Scael.Dt MEM 4 hp300 1047672Scael.Os 1147672Scael.Sh NAME 1247672Scael.Nm mem , 1347672Scael.Nm kmem 1447672Scael.Nd main memory 1547672Scael.Sh DESCRIPTION 1644666SbosticThe file 1747672Scael.Nm /dev/mem 1847672Scaelis an interface to the physical memory of the 1947672Scaelcomputer. 2047672ScaelByte offsets in this file are interpreted as physical memory addresses. 2147672ScaelReading and writing this file is equivalent to reading and writing 2247672Scaelmemory itself. 2347672ScaelAn error will be returned if an attempt is made to reference 2447672Scaelan offset outside of 2547672Scael.Nm /dev/mem . 2647672Scael.Pp 2747672ScaelKernel virtual memory is accessed via the file 2847672Scael.Nm /dev/kmem 2947672Scaelin the same manner as 3047672Scael.Nm /dev/mem . 3147672ScaelOnly kernel virtual addresses that are currently mapped to memory are allowed. 3247672Scael.Sh HP300 3347672ScaelOn the 3447672Scael.Tn HP300 , 3547672Scaelthe last byte of physical memory is always 3647672Scael.Li 0xFFFFFFFF . 3747672ScaelTherefore, on an 3847672Scael.Tn HP300 3947672Scaelwith 4047672Scael8Mb of memory, physical memory would start 4147672Scaelat 4247672Scael.Li 0xFF800000 . 4347672ScaelOn the 4447672Scael.Tn HP300 , 4547672Scaelkernel virtual memory runs from 4647672Scael.Li 0 4747672Scaelto about 4847672Scael.Li 0x2400000 . 4947672Scael.Sh FILES 5047672Scael.Bl -tag -width /dev/kmem -compact 5147672Scael.It Pa /dev/mem 5247672Scael.It Pa /dev/kmem 5347672Scael.El 5447672Scael.Sh HISTORY 5547672ScaelThe files 5647672Scael.Nm mem 5747672Scaeland 5847672Scael.Nm kmem 5947672Scaelappeared in 6047672Scael.At v6 . 61