| XBDBACK(4) | Device Drivers Manual (xen) | XBDBACK(4) | 
xbdback —
pseudo-device xbdback
xbdback interface forms the backend part of the
  paravirtualized drivers used by Xen domains to offer a block device interface,
  similar to a hard disk. xbdback interfaces are backed
  either by a physical device directly, or an image file mounted through
  vnd(4).
All xbdback interfaces follow the
    “xbdbackXiY” naming convention, where ‘X’
    represents the guest domain identifier, and ‘Y’ an arbitrary
    identifier. This identifier is usually associated to the device node as seen
    by the guest using major(3) and
    minor(3) numbers. For example,
    identifier “769” (0x301) means major 3 and
    minor 1, identified as “hda1” under Linux
    convention. For NetBSD, the guest device name
    specified in the guest configuration file does not matter, and can be chosen
    arbitrarily.
A xbdback interface will appear as a
    xbd(4) block device inside a
    NetBSD guest domain. In the XenStore,
    xbd and xbdback are
    identified by “vbd” (virtual block device) entries.
xbdback interface for the
      given guest domain, and its size, in bytes.EBUSY), the device is likely to be already
      mounted. It must be unmounted first, as the system will refuse to open it
      a second time.xbdback driver first appeared in
  NetBSD 4.0.
xbdback driver was written by
  Manuel Bouyer
  <bouyer@NetBSD.org>.
| June 7, 2011 | NetBSD 10.0 |