busTRACE This WEB page comes from the busTRACE 8.0 User's Manual. (Table of Contents)

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busFAULT allows you to simulate a failure on one or more CDBs sent to a specified device. For example, you can specify that all Write commands sent to a disk drive fail with a user specified return value. This feature can be beneficial for several reasons including:

  • Allows MultiPath users to force a failure on one device to test failover handling
  • Allows software engineers and test engineers to force a failure on a device to test how the software handles unexpected failures

To gain access to this application, simply run the busTRACE Start Menu and choose the Simulate a failure on one or more specified devices option.

Device List

On the left-most side of the window, busFAULT displays the list of devices where you can force a fault to occur. You simply select the device you want to generate the fault on and adjust the fault settings in the Settings window to the right.

The devices listed here are the same devices that appear within the main busTRACE application. To adjust which devices busFAULT and busTRACE support, click on the Driver Settings button in the lower left.

NOTE: Only those devices that busFAULT support can be selected. Those devices that do not process CDBs (e.g. non-storage USB devices), will appear grayed out.


When you select a device from the device list, the available options will appear in the right Settings window. At the top of this window, you can select the type of fault you would like to generate:

When busFAULT is activated on a device, any I/O request (with matching criteria) sent to the device will FAIL. This could be an I/O request sent by the operating system or sent by a user application. Both SCSI Request Block IRPs and SCSI Pass Through IOCTLs are checked and faulted as requested. If you are faulting your Windows boot drive, you may cause system instability issues. Extra caution is recommended.

Options Button

If you click on the Options button (lower left), you can adjust how the list of devices are displayed:


Show "Drive Letter"

If one or more drive letters are attached to a displayed storage device, we will show the drive letter(s) next to the device name.

Show "Device ID"

If we are able to determine a device's location (e.g. Target ID, LUN, etc.), we will append the location information after the device name if you place a checkmark on this option.

Show "Device Pointer"

Placing a checkmark on this field will show you the PDEVICE_OBJECT pointer value for each device in the device tree. This is an advanced feature intended for kernel driver writers who require this level of information.