--- wikisrc/ports/xen/howto.mdwn	2014/12/24 08:32:49	1.27
+++ wikisrc/ports/xen/howto.mdwn	2014/12/24 14:35:23	1.28
@@ -250,6 +250,12 @@ As with non-Xen systems, you should have
 kernel that works without Xen) and fallback versions of the non-Xen
 kernel, Xen, and the dom0 kernel.
 
+The [HowTo on Installing into
+RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)
+explains how to set up booting a dom0 with Xen using grub with
+NetBSD's RAIDframe.  (This is obsolete with the use of NetBSD's native
+boot.)
+
 Configuring Xen
 ---------------
 
@@ -298,8 +304,58 @@ Ensure that the contents of /etc/rc.d/xe
 correct set of daemons.  Ensure that the domU config files are valid
 for the new version.
 
-Creating unprivileged domains (domU)
-====================================
+
+Unprivileged domains (domU)
+===========================
+
+This section describes general concepts about domUs.  It does not
+address specific domU operating systems or how to install them.
+
+Provided Resources for PV domains
+---------------------------------
+
+TODO: Explain that domUs get cpu, memory, disk and network.
+Explain that randomness can be an issue.
+
+Virtual disks
+-------------
+
+TODO: Explain how to set up files for vnd and that one should write all zeros to preallocate.
+TODO: Explain in what NetBSD versions sparse vnd files do and don't work.
+
+Virtual Networking
+------------------
+
+TODO: explain xvif concept, and that it's general.
+
+There are two normal styles: bridging and NAT.
+
+With bridging, the domU perceives itself to be on the same network as
+the dom0.  For server virtualization, this is usually best.
+
+With NAT, the domU perceives itself to be behind a NAT running on the
+dom0.  This is often appropriate when running Xen on a workstation.
+
+One can construct arbitrary other configurations, but there is no
+script support.
+
+Config files
+------------
+
+TODO: give example config files.   Use both lvm and vnd.
+
+TODO: explain the mess with 3 arguments for disks and how to cope (0x1).
+
+Starting domains
+----------------
+
+TODO: Explain "xm start" and "xl start".  Explain rc.d/xendomains.
+
+TODO: Explain why 4.1 rc.d/xendomains has xl, when one should use xm
+on 4.1.
+
+Creating specific unprivileged domains (domU)
+=============================================
 
 Creating domUs is almost entirely independent of operating system.  We
 first explain NetBSD, and then differences for Linux and Solaris.
@@ -447,7 +503,7 @@ working vif-bridge is also provided with
 
     #!/bin/sh
     #============================================================================
-    # $NetBSD: howto.mdwn,v 1.26 2014/12/24 01:38:26 gdt Exp $
+    # $NetBSD: howto.mdwn,v 1.27 2014/12/24 08:32:49 jnemeth Exp $
     #
     # /usr/pkg/etc/xen/vif-bridge
     #
@@ -824,13 +880,16 @@ to use PCI devices in a domU. Here's a k
     sd*     at scsibus? target ? lun ?      # SCSI disk drives
     cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives
 
-Links and further information
-=============================
 
--   The [HowTo on Installing into RAID-1](http://mail-index.NetBSD.org/port-xen/2006/03/01/0010.html)
-    explains how to set up booting a dom0 with Xen using grub 
-    with NetBSD's RAIDframe.  (This is obsolete with the use of
-    NetBSD's native boot.)
--   An example of how to use NetBSD's native bootloader to load
-    NetBSD/Xen instead of Grub can be found in the i386/amd64 boot(8)
-    and boot.cfg(5) manpages.
+NetBSD as a domU in a VPS
+=========================
+
+The bulk of the HOWTO is about using NetBSD as a dom0 on your own
+hardware.  This section explains how to deal with Xen in a domU as a
+virtual private server where you do not control or have access to the
+dom0.
+
+TODO: Perhaps reference panix, prmgr, amazon as interesting examples.
+
+TODO: Somewhere, discuss pvgrub and py-grub to load the domU kernel
+from the domU filesystem.