Mentioned how to use /dev/vda without /dev/sr1 link

doc/qemu_xorriso.wiki

@@ -59,11 +59,17 @@ which had access to the Internet when the guest was installed.
 
 Preparations on guest system Debian GNU/Linux 6.0.3 i386
 
-There appears no /dev/sr for the passthrough drive. Since libburn
+There appears no /dev/sr for the passthrough drive. Thus libburn will not
-on Linux currently insists in finding a /dev/sr which points to the
+list it by its drive search function. One may use it nevertheless. But
-drive, there is need for an udev rule.
+xorriso will only do so if prefix "mmc:" is used with the address:
+{{{
+  -dev mmc:/dev/vda
+}}}
+The drive will be listed by libburn if there is a symbolic link /dev/sr*
+pointing to it. On Debian 6, this link persists only if it is created
+by an udev rule.
 
-/lib/udev/rules.d/50-udev-default.rules:
+In /lib/udev/rules.d/50-udev-default.rules:
 {{{
     KERNEL=="vda", SYMLINK+="sr1"
 }}}
@@ -72,6 +78,8 @@ libburn on Linux needs rw-permission for the drive's device node.
 The virtual device /dev/vda is in group "disk". Usual for CD drives is
 group "cdrom", to which i (or the Debian installer ?) have added my
 normal user when i installed the guest system.
+Like with the symbolic link, such a change persists on Debian 6 only as
+udev rule.
 
 In /lib/udev/rules.d/91-permissions.rules:
 {{{
@@ -291,8 +299,9 @@ Blanking to multi-session capability:
   $ xorriso -outdev /dev/sr1 -blank as_needed
 }}}
 This will need as long as writing the DVD-RW up to its end.
-Blanking option "as_neede" lets xorriso decide what to do in order
+Blanking option "as_needed" lets xorriso decide what to do in order
-to make the medium type writable from scratch.
+to make the medium writable from scratch. With DVD-RW it will decide for
+-blank "all".
 
 The report on stderr should end by
 {{{
@@ -310,7 +319,7 @@ The report on stderr should end by
 
 ----------------------------------------------------------------------
  
-Writing multiple sessions (DVD-R write type Incremental):
+Writing multiple sessions (DVD-RW write type Incremental):
 
 This time do not perform command  -close "on", so that the medium
 stays writable: