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Describe slices and partitions a little better.

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An an aside, most of this part of the chapter is marked up
incorrectly--e.g., <quote> is used where something like <devicename>
is much more appropriate.  This delta doesn't help, but keeps things
relatively consistent.

PR:		30062
Submitted by:	Mike Meyer <mwm@mired.org>
This commit is contained in:
Dima Dorfman 2001-08-28 12:36:43 +00:00
parent cd4ba70ca7
commit bcf62d4c42
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=10485
1 changed files with 27 additions and 8 deletions
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35
en_US.ISO8859-1/books/handbook/disks/chapter.sgml
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@ -1,7 +1,7 @@
<!--
The FreeBSD Documentation Project
$FreeBSD: doc/en_US.ISO8859-1/books/handbook/disks/chapter.sgml,v 1.55 2001/08/24 01:05:20 logo Exp $
$FreeBSD: doc/en_US.ISO8859-1/books/handbook/disks/chapter.sgml,v 1.56 2001/08/24 20:44:08 chern Exp $
-->
<chapter id="disks">
@ -177,7 +177,7 @@
<literal>wcd</literal> before 4.0-RELEASE.</entry>
</row>
<row>
<entry>SCSI hard drives</entry>
<entry>SCSI hard drives and USB Mass storage devices</entry>
<entry><literal>da</literal> from 3.0-RELEASE,
<literal>sd</literal> before 3.0-RELEASE.</entry>
</row>
@ -223,6 +223,11 @@
</tgroup>
</table>
<para>All the drives attached through a specific driver are
numbered starting at 0. So the first IDE drive would be
<quote>ad<emphasis>0</emphasis></quote>. You seldom need to use
these devices.</para>
<sect2 id="slicesandpartitions">
<title>Slices and Partitions</title>
<indexterm><primary>slices</primary></indexterm>
@ -231,17 +236,31 @@
<para>Physical disks usually contain
<firstterm>slices</firstterm>, unless they are
<quote>dangerously dedicated</quote>. Slice numbers follow
the device name, prefixed with an <literal>s</literal>:
<quote>da0<emphasis>s1</emphasis></quote>.</para>
the device name, prefixed with an <literal>s</literal>,
starting at 1. So <quote>da0<emphasis>s1</emphasis></quote>
is the first slice on the first SCSI drive. There can only be
four physical slices on a disk, but you can have logical
slices inside physical slices of the appropriate type. These
extended slices are numbered starting at 5, so
<quote>ad0<emphasis>s5</emphasis></quote> is the first
extended slice on a disk. These devices are used by file
systems that expect to occupy a slice.</para>
<para>Slices, <quote>dangerously dedicated</quote> physical
drives, and other drives contain
<firstterm>partitions</firstterm>, which are represented as
letters from <literal>a</literal> to <literal>h</literal>.
<literal>b</literal> is reserved for swap partitions, and
<literal>c</literal> is an unused partition the size of the
entire slice or drive. This is explained in <xref
linkend="disks-adding">.</para>
This letter is appended to the device name, so
<quote>da0<emphasis>a</emphasis></quote> is the a partition on
the first da drive, which is <quote>dangerously dedicated</quote>.
<quote>ad1s3<emphasis>e</emphasis></quote> is the fifth partition
in the third slice of the second IDE disk drive.</para>
<para>The boot code expects partition <literal>a</literal> to be
the root partition. Partition <literal>b</literal> is normally
reserved for swap partitions, and <literal>c</literal> is an
unused partition the size of the entire slice or drive. This
is explained in <xref linkend="disks-adding">.</para>
</sect2>
</sect1>