svn commit: r53529 - head/en_US.ISO8859-1/htdocs/releases/12.1R/relnotes

[Glen Barber]

Author: gjb
Date: Sun Nov  3 23:56:24 2019
New Revision: 53529
URL: https://svnweb.freebsd.org/changeset/doc/53529

Log:
  Add a note regarding the default CPUTYPE starting with 13.0.
  
  Submitted by:	imp
  Sponsored by:	Rubicon Communications, LLC (netgate.com)

Modified:
  head/en_US.ISO8859-1/htdocs/releases/12.1R/relnotes/relnotes.xml

Modified: head/en_US.ISO8859-1/htdocs/releases/12.1R/relnotes/relnotes.xml
==============================================================================
--- head/en_US.ISO8859-1/htdocs/releases/12.1R/relnotes/relnotes.xml	Sun Nov  3 20:41:24 2019	(r53528)
+++ head/en_US.ISO8859-1/htdocs/releases/12.1R/relnotes/relnotes.xml	Sun Nov  3 23:56:24 2019	(r53529)
@@ -791,4 +791,55 @@
 	1.12.0.</para>
     </sect2>
   </sect1>
+
+  <sect1 xml:id="future-releases">
+    <title>General Notes Regarding Future &os; Releases</title>
+
+    <sect2 xml:id="future-releases-cputype">
+      <title>Default <varname>CPUTYPE</varname> Change</title>
+
+      <para>Starting with &os;-13.0, the default
+	<varname>CPUTYPE</varname> for the &arch.i386;
+	architecture will change from <literal>486</literal> to
+	<literal>686</literal>.</para>
+
+      <para>This means that, by default, binaries produced will
+	require a 686-class <acronym>CPU</acronym>, including but
+	not limited to binaries provided by the &os; Release
+	Engineering team.  &os; 13.0 will continue to support
+	older <acronym>CPU</acronym>s, however users needing this
+	functionality will need to build their own releases for
+	official support.</para>
+
+      <para>As the primary use for i486 and i586
+	<acronym>CPU</acronym>s is generally in the embedded market,
+	the general end-user impact is expected to be minimal, as new
+	hardware with these <acronym>CPU</acronym> types has long
+	faded, and much of the deployed base of such systems is
+	nearing retirement age, statistically.</para>
+
+      <para>There were several factors taken into account for this
+	change.  For example, i486 does not have 64-bit atomics, and
+	while they can be emulated in the kernel, they cannot be
+	emulated in the userland.  Additionally, the 32-bit amd64
+	libraries have been i686 since their inception.</para>
+
+      <para>As the majority of 32-bit testing is done by developers
+	using the lib32 libraries on 64-bit hardware with the
+	<varname>COMPAT_FREEBSD32</varname> option in the kernel,
+	this change ensures better coverage and user experience.
+	This also aligns with what the majority of &linux;
+	distributions have been doing for quite some time.</para>
+
+      <para>This is expected to be the final bump of the default
+	<varname>CPUTYPE</varname> in &arch.i386;.</para>
+
+      <para>
+	<important>
+	  <para>This change does not affect the &os; 12.x
+	    series of releases.</para>
+	</important>
+      </para>
+    </sect2>
+  </sect1>
 </article>