svn commit: r40110 - head/en_US.ISO8859-1/books/faq

[Eitan Adler]

Author: eadler
Date: Tue Nov 20 18:25:04 2012
New Revision: 40110
URL: http://svnweb.freebsd.org/changeset/doc/40110

Log:
  Disk geometry stopped being a problem around 1997.
  
  Noted by:	scottl
  Approved by:	bcr (mentor)

Modified:
  head/en_US.ISO8859-1/books/faq/book.xml

Modified: head/en_US.ISO8859-1/books/faq/book.xml
==============================================================================
--- head/en_US.ISO8859-1/books/faq/book.xml	Tue Nov 20 18:24:58 2012	(r40109)
+++ head/en_US.ISO8859-1/books/faq/book.xml	Tue Nov 20 18:25:04 2012	(r40110)
@@ -1476,81 +1476,6 @@
       </qandaentry>
 
       <qandaentry>
-	<question id="geometry">
-	  <para>Which geometry should I use for a disk drive?</para>
-	</question>
-
-	<answer>
-	    <note>
-	      <para>By the <quote>geometry</quote> of a disk, we mean
-		the number of cylinders, heads and sectors/track on a
-		disk.  We will refer to this as C/H/S for convenience.
-		This is how the PC's BIOS works out which area on a disk
-		to read/write from.</para>
-	    </note>
-
-	  <para>This causes a lot of confusion among new system
-	    administrators.  First of all, the
-	    <emphasis>physical</emphasis> geometry of a SCSI drive is
-	    totally irrelevant, as &os; works in term of disk blocks.
-	    In fact, there is no such thing as <quote>the</quote>
-	    physical geometry, as the sector density varies across the
-	    disk.  What manufacturers claim is the <quote>physical
-	    geometry</quote> is usually the geometry that they have
-	    determined wastes the least space.  For IDE disks, &os; does
-	    work in terms of C/H/S, but all modern drives internally
-	    convert this into block references.</para>
-
-	  <para>All that matters is the <emphasis>logical</emphasis>
-	    geometry.  This is the answer that the BIOS gets when it
-	    asks the drive <quote>what is your geometry?</quote> It then
-	    uses this geometry to access the disk.  As &os; uses the
-	    BIOS when booting, it is very important to get this right.
-	    In particular, if you have more than one operating system on
-	    a disk, they must all agree on the geometry.  Otherwise you
-	    will have serious problems booting!</para>
-
-	  <para>For SCSI disks, the geometry to use depends on whether
-	    extended translation support is turned on in your controller
-	    (this is often referred to as <quote>support for DOS disks
-	    >1GB</quote> or something similar).  If it is turned off,
-	    then use <replaceable>N</replaceable> cylinders, 64 heads
-	    and 32 sectors/track, where <replaceable>N</replaceable> is
-	    the capacity of the disk in MB.  For example, a 2 GB disk
-	    should pretend to have 2048 cylinders, 64 heads and 32
-	    sectors/track.</para>
-
-	  <para>If it <emphasis>is</emphasis> turned on (it is often
-	    supplied this way to get around certain limitations in
-	    &ms-dos;) and the disk capacity is more than 1 GB, use
-	    <replaceable>M</replaceable> cylinders, 63 sectors per track
-	    (<emphasis>not</emphasis> 64), and 255 heads, where
-	    <replaceable>M</replaceable> is the disk capacity in MB
-	    divided by 7.844238 (!).  So our example 2 GB drive
-	    would have 261 cylinders, 63 sectors per track and 255
-	    heads.</para>
-
-	  <para>If you are not sure about this, or &os; fails to detect
-	    the geometry correctly during installation, the simplest way
-	    around this is usually to create a small DOS partition on
-	    the disk.  The BIOS should then detect the correct geometry,
-	    and you can always remove the DOS partition in the partition
-	    editor if you do not want to keep it.  You might want to
-	    leave it around for programming network cards and the like,
-	    however.</para>
-
-	  <para>Alternatively, there is a freely available utility
-	    distributed with &os; called
-	    <filename>pfdisk.exe</filename>.  You can find it in the
-	    <filename class="directory">tools</filename> subdirectory on
-	    the &os; CD-ROM or on the various &os; FTP sites.  This
-	    program can be used to work out what geometry the other
-	    operating systems on the disk are using.  You can then enter
-	    this geometry in the partition editor.</para>
-	</answer>
-      </qandaentry>
-
-      <qandaentry>
 	<question id="disk-divide-restrictions">
 	  <para>Are there any restrictions on how I divide the disk
 	    up?</para>
@@ -1606,8 +1531,8 @@
 
 	<answer>
 	  <para>This is classically a case of &os; and some other
-	    OS conflicting over their ideas of disk <link
-	      linkend="geometry">geometry</link>.  You will have to
+	    OS conflicting over their ideas of disk
+	      geometry.  You will have to
 	    reinstall &os;, but obeying the instructions given above
 	    will almost always get you going.</para>
 	</answer>