[src/trunk]: src/share/man/man4 Document the naming convention.

[jym <jym%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/34cdbf557e9b
branches:  trunk
changeset: 765841:34cdbf557e9b
user:      jym <jym%NetBSD.org@localhost>
date:      Tue Jun 07 17:13:43 2011 +0000

description:
Document the naming convention.

diffstat:

 share/man/man4/xbdback.4 |  36 ++++++++++++++++++++++++++++++------
 1 files changed, 30 insertions(+), 6 deletions(-)

diffs (62 lines):

diff -r 24f9397970f5 -r 34cdbf557e9b share/man/man4/xbdback.4
--- a/share/man/man4/xbdback.4  Tue Jun 07 16:41:14 2011 +0000
+++ b/share/man/man4/xbdback.4  Tue Jun 07 17:13:43 2011 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: xbdback.4,v 1.2 2011/01/11 10:48:05 wiz Exp $
+.\"    $NetBSD: xbdback.4,v 1.3 2011/06/07 17:13:43 jym Exp $
 .\"
 .\" Copyright (c) 2011 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -27,7 +27,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd January 8, 2011
+.Dd June 7, 2011
 .Dt XBDBACK 4 xen
 .Os
 .Sh NAME
@@ -42,15 +42,39 @@
 used by
 .Tn Xen
 domains to offer a block device interface, similar to a hard disk.
+.Nm
+interfaces are backed either by a physical device directly,
+or an image file mounted through
+.Xr vnd 4 .
 .Pp
+All
+.Nm
+interfaces follow the
+.Dq xbdbackXiY
+naming convention, where
+.Sq X
+represents the guest domain identifier, and
+.Sq Y
+an arbitrary identifier.
+This identifier is usually associated to the device node as seen
+by the guest using
+.Xr major 3
+and
+.Xr minor 3
+numbers.
+For example, identifier
+.Do 769 Dc Po 0x301 Pc
+means major
+.Em 3
+and minor
+.Em 1 ,
+identified as
+.Dq hda1
+under Linux convention.
 For
 .Nx ,
 the guest device name specified in the guest configuration file
 does not matter, and can be chosen arbitrarily.
-.Nm
-interfaces are backed either by a physical device directly,
-or an image file mounted through
-.Xr vnd 4 .
 .Pp
 A
 .Nm