BSD 4_3_Net_2 release

[unix-history] / usr / src / share / man / man4 / man4.tahoe / mem.4

diff --git a/usr/src/share/man/man4/man4.tahoe/mem.4 b/usr/src/share/man/man4/man4.tahoe/mem.4
index 6e50635..e27f53f 100644 (file)
--- a/usr/src/share/man/man4/man4.tahoe/mem.4
+++ b/usr/src/share/man/man4/man4.tahoe/mem.4
@@ -1,70 +1,127 @@
-.\" Copyright (c) 1986 Regents of the University of California.
-.\" All rights reserved.  The Berkeley software License Agreement
-.\" specifies the terms and conditions for redistribution.
+.\" Copyright (c) 1986, 1991 Regents of the University of California.
+.\" All rights reserved.

 .\"
 .\"

-.\"    @(#)mem.4       6.2 (Berkeley) 6/30/87
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"    This product includes software developed by the University of
+.\"    California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.

 .\"
 .\"

-.TH MEM 4 "June 30, 1987"
-.UC 7
-.SH NAME
-mem, kmem, vmem \- main memory
-.SH DESCRIPTION
-.lg
-.I Mem
-is a special file that is an image of the main memory
-of the computer.
-It may be used, for example, to examine
-(and even to patch) the system.
-.PP
-Byte addresses in
-.I mem
-are interpreted as physical memory addresses.
-References to non-existent locations cause errors to be returned.
-.PP
-Examining and patching device registers is likely
-to lead to unexpected results when read-only or write-only
-bits are present.
-.PP
-The file
-.I kmem
-is the same as 
-.I mem
-except that kernel virtual memory
-rather than physical memory is accessed.
-.PP
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     @(#)mem.4      6.3 (Berkeley) 3/27/91
+.\"
+.Dd March 27, 1991
+.Dt MEM 4 tahoe
+.Os
+.Sh NAME
+.Nm mem ,
+.Nm kmem ,
+.Nm vmem
+.Nd main memory
+.Sh DESCRIPTION
+The special file
+.Nm /dev/mem
+is an interface to the physical memory of the computer.
+Byte offsets in this file are interpreted as physical memory addresses.
+Reading and writing this file is equivalent to reading and writing
+memory itself.
+Only offsets within the bounds of
+.Nm /dev/mem
+are allowed.
+.Pp
+Kernel virtual memory is accessed through the interface
+.Nm /dev/kmem
+in the same manner as
+.Nm /dev/mem .
+Only kernel virtual addresses that are currently mapped to memory are allowed.
+.Pp

 The file
 The file

-.I vmem
-allows access to the mapped portion of the VERSAbus
-i/o space.  On the Tahoe the upper megabyte
+.Nm /dev/vmem
+allows access to the mapped portion of the
+.Tn VERSAbus
+.Tn I/O
+space.  On the Tahoe the upper megabyte

 of the physical address space is accessible through
 this file (0xfff00000 through 0xffffffff). 
 Accesses to the upper 64 kilobytes of
 of the physical address space is accessible through
 this file (0xfff00000 through 0xffffffff). 
 Accesses to the upper 64 kilobytes of

-the i/o space result in VERSAbus transfers with a
+the
+.Tn I/O
+space result in
+.Tn VERSAbus
+transfers with a

 16-bit address (the offset in this region) and a
 16-bit address (the offset in this region) and a

-``non-privileged short i/o'' VERSAbus address modifier.
+.Dq No non-privileged short Tn I/O
+.Tn VERSAbus
+address modifier.

 Accesses to the remainder of the mapped region,
 Accesses to the remainder of the mapped region,

-result in VERSAbus transfers with a 24-bit address
-and a ``non-privileged standard'' VERSAbus address
+result in
+.Tn VERSAbus
+transfers with a 24-bit address
+and a ``non-privileged standard''
+.Tn VERSAbus
+address

 modifier.  This region is actually part of the region
 between 0xfeff0000 and 0xffff0000
 modifier.  This region is actually part of the region
 between 0xfeff0000 and 0xffff0000

-which generates VERSAbus transfers with a 24-bit address.
-Accesses to the remainder of the one gigabyte i/o space
+which generates
+.Tn VERSAbus
+transfers with a 24-bit address.
+Accesses to the remainder of the one gigabyte
+.Tn I/O
+space

 generate transfers that utilize a 32-bit address with
 a ``non-privileged extended'' address modifier.  Any
 32-bit address generated by a cpu access to this part
 generate transfers that utilize a 32-bit address with
 a ``non-privileged extended'' address modifier.  Any
 32-bit address generated by a cpu access to this part

-of the i/o space have the upper two bits zero; thus,
+of the
+.Tn I/O
+space have the upper two bits zero; thus,

 for example, an access to physical address 0xfe000000
 causes the address 0x3e000000 to be supplied in the
 for example, an access to physical address 0xfe000000
 causes the address 0x3e000000 to be supplied in the

-resultant VERSAbus read/write cycle.
-.PP
+resultant
+.Tn VERSAbus
+read/write cycle.
+.Pp

 On the Tahoe, the 
 On the Tahoe, the 

-per-process data for the current process
-begins at virtual address 0xbffff000.
-.SH FILES
-/dev/mem,
-/dev/kmem,
-/dev/vmm
-.SH BUGS
+base address for the
+per-process data of the current process
+is virtual address 0xbffff000.
+.Sh FILES
+.Bl -tag -width Pa -compact
+.It Pa /dev/mem
+.It Pa /dev/kmem
+.It Pa /dev/vmm
+.El
+.Sh HISTORY
+The
+.Nm mem ,
+.Nm kmem
+files appeared in
+.At v6 .
+The file
+.Nm vmem
+appeared in
+.Bx 4.3 tahoe .
+.Sh BUGS

 Memory files are accessed one byte
 at a time, an inappropiate method for some
 device registers.
 Memory files are accessed one byte
 at a time, an inappropiate method for some
 device registers.