220 lines
4.8 KiB
HTML
220 lines
4.8 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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>Floppies</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="Using Disks and Other Storage Media"
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HREF="disk-usage.html"><LINK
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REL="PREVIOUS"
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TITLE="Network Attached Storage - Draft"
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HREF="net-attached.html"><LINK
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REL="NEXT"
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TITLE="CD-ROMs"
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HREF="cdrom.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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ALINK="#0000FF"
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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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BORDER="0"
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CELLPADDING="0"
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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="net-attached.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 5. Using Disks and Other Storage Media</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="cdrom.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="FLOPPIES"
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></A
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>5.5. Floppies</H1
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><P
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>A floppy disk
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consists of a flexible membrane covered on one
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or both sides with similar magnetic substance as a hard disk. The
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floppy disk itself doesn't have a read-write head, that is included
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in the drive. A floppy corresponds to one platter in a hard disk,
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but is removable and one drive can be used to access different
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floppies, and the same floppy can be read by many drives, whereas
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the hard disk is one indivisible unit.</P
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><P
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>Like a hard disk, a floppy is divided into tracks and sectors
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(and the two corresponding tracks on either side of a floppy
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form a cylinder), but there are many fewer of them than on a
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hard disk.</P
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><P
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>A floppy drive can usually use several different types of disks;
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for example, a 3.5 inch drive can use both 720 KB and 1.44 MB disks.
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Since the drive has to operate a bit differently and the operating
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system must know how big the disk is, there are many device files
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for floppy drives, one per combination of drive and disk type.
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Therefore, <TT
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CLASS="FILENAME"
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>/dev/fd0H1440</TT
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> is the first floppy
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drive (fd0), which must be a 3.5 inch drive, using a 3.5 inch, high
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density disk (H) of size 1440 KB (1440), i.e., a normal 3.5 inch HD
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floppy.
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</P
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><P
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>The names for floppy drives are complex, however, and Linux
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therefore has a special floppy device type that automatically
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detects the type of the disk in the drive. It works by trying to
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read the first sector of a newly inserted floppy using different
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floppy types until it finds the correct one. This naturally requires
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that the floppy is formatted first. The automatic devices are called
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<TT
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CLASS="FILENAME"
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>/dev/fd0</TT
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>,
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<TT
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CLASS="FILENAME"
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>/dev/fd1</TT
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>, and so
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on.</P
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><P
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>The parameters the automatic device uses to access a disk can
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also be set using the program <B
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CLASS="COMMAND"
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>setfdprm</B
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>
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. This can
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be useful if you need to use disks that do not follow any usual
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floppy sizes, e.g., if they have an unusual number of sectors, or if
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the autodetecting for some reason fails and the proper device file is
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missing.</P
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><P
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>Linux can handle many nonstandard floppy disk formats
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in addition to all the standard ones. Some of these require using
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special formatting programs. We'll skip these disk types for now,
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but in the mean time you can examine the
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<TT
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CLASS="FILENAME"
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>/etc/fdprm</TT
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> file. It specifies the settings
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that <B
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CLASS="COMMAND"
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>setfdprm</B
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> recognizes.</P
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><P
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>The operating system must know when a disk has been changed in
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a floppy drive, for example, in order to avoid using cached data
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from the previous disk. Unfortunately, the signal line that is used
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for this is sometimes broken, and worse, this won't always be
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noticeable when using the drive from within MS-DOS. If you are
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experiencing weird problems using floppies, this might be the
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reason. The only way to correct it is to repair the floppy drive.</P
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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SUMMARY="Footer navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="net-attached.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="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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ACCESSKEY="H"
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>Home</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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><A
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HREF="cdrom.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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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>Network Attached Storage - Draft</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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><A
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HREF="disk-usage.html"
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ACCESSKEY="U"
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>Up</A
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></TD
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><TD
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WIDTH="33%"
|
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ALIGN="right"
|
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VALIGN="top"
|
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>CD-ROMs</TD
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></TR
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></TABLE
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></DIV
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></BODY
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></HTML
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> |