DeviceTree is a driver development support
utility that allows the user to examine the Device Objects and Driver Objects
present in a system. The utility also
shows the relations among these objects.
DeviceTree is useful for driver and system
debugging and diagnosis.
The current version of DeviceTree is V2.6 – While the tool has been successfully
tested in a wide-variety of environments on Windows XP and Windows 2000, users
must recognize that it is a support utility for use by knowledgeable kernel
mode developers in test environments.
Because of the depth of the information that it gathers and reports, DeviceTree is capable of crashing the system. Though these crashes are extremely rare, we
recommend that DeviceTree not be used on production
systems.
DeviceTree was written by OSR Open Systems
Resources, Inc. (http://www.osr.com) and is
distributed in the Windows DDK under license.
DeviceTree requires administrator privilege
to run. It may not be run from a remote
disk volume or via terminal server – it must be run from a local disk drive.
DeviceTree has two “views” – The Driver view
(shown by pressing the D button on DeviceTree’s
tool bar) and the PnP view (shown by pressing the P button on DeviceTree’s tool bar).
The Driver view lists all
the drivers in the system, by name, and the Device Objects associated with
these drivers. Selecting
a driver or Device Object in the left pane of DeviceTree
results in detailed information being displayed about the selected object in
the right pane. Unnamed Device
Objects are indicated by the name “(unnamed)”.
In the Driver view, the details displayed in the right pane include
driver name, load address, size, handle count, and which I/O and Fast I/O
operations (if any) are supported by the driver. A summary of devices owned by the driver is
also shown.
Driver Objects are
denoted by DRV in the Driver
view. Device Objects owned by the Driver
Object are shown under the Driver Object with the legend DEV. Where one Device Object has another Device
Object attached, either via the AttachedDevices
pointer or via a Volume Parameter Block (VPB), the Device Object that is
attached is shown with the legend ATT.
The Plug and Play view shows
the Device Objects in the system and their relationship to each other in the
Plug and Play “Device Tree”. The left
pane starts with the root of the tree, the “Root Enumerator” (the PnP Manager). Expanding a level in the tree shows the
devices enumerated at that level. An
individual branch of the PnP device tree may thus be expanded from its root (on
the left) all the way to a particular leaf (on the right).
When a Device Object is
selected in the left pane, detailed information is shown about that Device
Object in the right pane.
A few points regarding
the notation used in the Plug and Play view might be useful. PDO indicates a Device Object that is
a Physical Device Object. FDO
indicates a Device Object that is either a Functional Device Object or a Filter
driver Functional Device Object. As
knowledgeable kernel-mode developers will know, a PnP driver instantiates a
Functional Device Object over the Physical Device Object created by an
underlying bus driver. A FDO layered
over an PDO is shown above, or “further to the right”
in DeviceTree’s display. When an FDO is shown to be layered over
another FDO, the second FDO is likely to be the Device Object for a filter
driver. When a PDO is shown in color
(purple), it indicates a PDO that has been reported as owned by it’s preceding FDO, but that is actually owned by another
driver.
DeviceTree supports IA32 architecture
Windows 2000 and Windows XP systems. It
does support Microsoft Windows 95, Microsoft Windows 98, Microsoft
Windows Millennium. It does not support
any IA64 configuration at the present time.
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