The Capture Devices pane shows you the list of devices that busTRACE can capture I/O activity against. A hierarchical device tree will appear showing you the controllers and the devices that connect to them. For example:

By placing a checkmark next to a device, you are specifying that you would like to capture I/O activity going to that device. By removing the checkmark, no I/O activity for that device will be captured. You can set or remove the checkmark at any time, even while the busTRACE capture is active.

• If you hold down the shift key while clicking a tree item with children, all child items of the selected item will also have their capture status checked or unchecked (i.e. recursive selection).
• If you hold down the shift key while clicking a tree item without children, and the currently selected device shares the same parent as the item whose checkbox you are altering, then all siblings between the two items will have their status checked or unchecked. This is often used to enable/disable the capture on a range of LUNs within the device tree.

Note how each device is given a unique icon / color icon. This same icon is displayed in the I/O Capture List when I/O is captured for the device. You can also click on the device icon color to select a new color from the drop color list. When capturing I/O activity across multiple devices simultaneously, this makes it easier for you to determine which device is being sent the I/O request.

busTRACE is fully Plug and Play aware. If you remove a device, or attach a device, busTRACE will automatically refresh itself to show you the new device tree.

The hierarchical view is showing you the list of devices as Windows has created them. If you are interested in capturing I/O activity for a device, you need to set a checkmark on that device, and not necessarily its parent item (i.e. the controller).

For example, if you have a "Plextor DVD Recorder" connected to the "Secondary IDE Channel," you would place a checkmark next to the Plextor device. Placing a checkmark next to the "Secondary IDE Channel item" will typically have no effect as I/Os are flowing to the device and not the controller. This can be confusing at first as it is true that I/Os do flow through the hardware controller. However, we're capturing I/O activity from the operating system's perspective. In Windows, I/Os are directed to the actual device object and not necessarily the controller object.

If you want to learn more about how Windows creates device objects, please review Microsoft's Windows Driver Development Kit.

Configuration Options

You can use the toolbar options, or right click on a device name, to alter the way devices are displayed to you or to filter out specific I/O activity. The System / Device Explorer option shows you detailed information about the system being analyzed.

Rescan SCSI/ATAPI Bus

As mentioned above, busTRACE is fully Plug and Play aware. However, not all bus architectures can detect if a device has been added or removed. For example, the parallel ATA/ATAPI bus and SCSI bus cannot detect if any such change has occurred.

Under busTRACE, you can request the OS to rescan its SCSI/ATAPI buses to see if any devices have been added or removed. Simply select Rescan SCSI/ATAPI Bus from the Tools main menu.

See Also:

• busTRACE Screen Layout
• System Explorer