450 lines
6.7 KiB
HTML
450 lines
6.7 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>Hardware Utilities </TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="Linux System Administrators Guide"
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HREF="index.html"><LINK
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REL="UP"
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TITLE="Hardware, Devices, and Tools"
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HREF="device-list.html"><LINK
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REL="PREVIOUS"
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TITLE="Hardware, Devices, and Tools"
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HREF="device-list.html"><LINK
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REL="NEXT"
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TITLE="Kernel Modules"
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HREF="x1926.html"></HEAD
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><BODY
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CLASS="SECT1"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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LINK="#0000FF"
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VLINK="#840084"
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><DIV
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CLASS="NAVHEADER"
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><TABLE
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SUMMARY="Header navigation table"
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WIDTH="100%"
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>Linux System Administrators Guide: </TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="device-list.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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>Chapter 4. Hardware, Devices, and Tools</TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="x1926.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="SECT1"
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><H1
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CLASS="SECT1"
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><A
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NAME="HWUTILS"
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></A
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>4.1. Hardware Utilities</H1
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="MAKEDEV"
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></A
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>4.1.1. The <B
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CLASS="COMMAND"
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>MAKEDEV</B
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> Script</H2
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><P
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>Most device files will already be created and will be there
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ready to use after you install your Linux system. If by some chance
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you need to create one which is not provided then you should first
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try to use the <B
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CLASS="COMMAND"
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>MAKEDEV</B
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> script. This script is
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usually located in <TT
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CLASS="FILENAME"
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>/dev/MAKEDEV</TT
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> but might also
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have a copy (or a symbolic link) in
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<TT
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CLASS="FILENAME"
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>/sbin/MAKEDEV</TT
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>. If it turns out not to be in
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your path then you will need to specify the path to it
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explicitly.</P
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><P
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>In general the command is used as:
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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> <TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>/dev/MAKEDEV -v ttyS0</B
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></TT
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>
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<TT
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CLASS="COMPUTEROUTPUT"
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>create ttyS0 c 4 64 root:dialout 0660</TT
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>
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</PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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This will create the device file <TT
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CLASS="FILENAME"
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>/dev/ttyS0</TT
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>
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with major node 4 and minor node 64 as a character device with
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access permissions 0660 with owner root and group dialout.</P
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><P
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><TT
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CLASS="FILENAME"
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>ttyS0</TT
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> is a serial port. The major and
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minor node numbers are numbers understood by the kernel. The kernel
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refers to hardware devices as numbers, this would be very difficult
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for us to remember, so we use filenames. Access permissions of 0660
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means read and write permission for the owner (root in this case)
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and read and write permission for members of the group (dialout in
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this case) with no access for anyone else.</P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="MKNOD"
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></A
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>4.1.2. The <B
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CLASS="COMMAND"
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>mknod</B
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> command</H2
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><P
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><B
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CLASS="COMMAND"
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>MAKEDEV</B
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> is the preferred way of creating
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device files which are not present. However sometimes the
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<B
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CLASS="COMMAND"
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>MAKEDEV</B
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> script will not know about the device
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file you wish to create. This is where the <B
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CLASS="COMMAND"
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>mknod</B
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>
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command comes in. In order to use <B
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CLASS="COMMAND"
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>mknod</B
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> you need
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to know the major and minor node numbers for the device you wish to
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create. The <TT
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CLASS="FILENAME"
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>devices.txt</TT
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> file in the kernel
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source documentation is the canonical source of this
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information.</P
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><P
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>To take an example, let us suppose that our version of the
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<B
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CLASS="COMMAND"
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>MAKEDEV</B
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> script does not know how to create the
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<TT
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CLASS="FILENAME"
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>/dev/ttyS0</TT
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> device file. We need
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to use <B
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CLASS="COMMAND"
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>mknod</B
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> to create it. We know from looking at the
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<TT
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CLASS="FILENAME"
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>devices.txt</TT
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> that it should be a character
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device with major number 4 and minor number 64. So we now know all
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we need to create the file.
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<TABLE
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BORDER="1"
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BGCOLOR="#E0E0E0"
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WIDTH="100%"
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><TR
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><TD
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><FONT
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COLOR="#000000"
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><PRE
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CLASS="SCREEN"
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> <TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>mknod /dev/ttyS0 c 4 64</B
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></TT
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>
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<TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>chown root.dialout /dev/ttyS0</B
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></TT
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>
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<TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>chmod 0644 /dev/ttyS0</B
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></TT
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>
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<TT
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CLASS="PROMPT"
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>#</TT
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> <TT
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CLASS="USERINPUT"
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><B
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>ls -l /dev/ttyS0</B
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></TT
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>
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<TT
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CLASS="COMPUTEROUTPUT"
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> crw-rw---- 1 root dialout 4, 64 Oct 23 18:23 /dev/ttyS0
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</TT
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>
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</PRE
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></FONT
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></TD
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></TR
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></TABLE
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>
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As you can see, many more steps are required to create the file. In
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this example you can see the process required however. It is
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unlikely in the extreme that the ttyS0 file would not be provided by
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the <B
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CLASS="COMMAND"
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>MAKEDEV</B
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> script, but it suffices to illustrate
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the point.</P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="LSPCI"
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></A
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>4.1.3. The <B
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CLASS="COMMAND"
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>lspci</B
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> command</H2
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><P
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>lspci</P
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><P
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>TO BE ADDED</P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="LSDEV"
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></A
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>4.1.4. The <B
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CLASS="COMMAND"
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>lsdev</B
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> command</H2
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><P
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>lsdev</P
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><P
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>TO BE ADDED</P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="LSUSB"
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></A
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>4.1.5. The <B
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CLASS="COMMAND"
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>lsusb</B
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> command</H2
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><P
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>lsusb</P
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><P
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>TO BE ADDED</P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="LSRAID"
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></A
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>4.1.6. The <B
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CLASS="COMMAND"
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>lsraid</B
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> command</H2
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><P
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>lsraid</P
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><P
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>TO BE ADDED</P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="HDPARM"
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></A
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>4.1.7. The <B
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CLASS="COMMAND"
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>hdparm</B
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> command</H2
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><P
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>hdparm</P
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><P
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>TO BE ADDED</P
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></DIV
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><DIV
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CLASS="SECT2"
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><H2
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CLASS="SECT2"
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><A
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NAME="MORE-HWRESOURCES"
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></A
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>4.1.8. More Hardware Resources</H2
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><P
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>More information on what hardware resources the kernel is using
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can be found in the <TT
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CLASS="FILENAME"
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>/proc</TT
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> directory. Refer to
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<A
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HREF="proc-fs.html"
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>Section 3.7</A
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> in chapter 3.
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</P
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></DIV
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></DIV
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CLASS="NAVFOOTER"
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VALIGN="top"
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HREF="device-list.html"
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ACCESSKEY="P"
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>Prev</A
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>Next</A
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>Hardware, Devices, and Tools</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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