busTRACE includes a powerful data corruption analysis feature. This feature only applies to storage class devices such as hard drives, solid state drives, and CD/DVD/BD drives.

When invoked, our data corruption analysis feature will look at all blocks read from the device and all blocks written to the device. If miscompares are detected, busTRACE will notify you where the failure occurred. For example, let's say all zeros are written to LBA 100 on your hard drive. Some time later, the LBA is read back but the first two bytes have FFh instead of 00h. In such a case, busTRACE will flag this as possible data corruption.

In addition to comparing read after writes, busTRACE will also compare reads against reads. For example, let's say the operating system reads back LBA 100 and it has all zeros. Later on, the OS re-reads LBA 100 (with no write occurring in between) and it is no longer all zeros. In such a case, busTRACE will also flag this as potential data corruption.

To enable this feature, simply select the Data Corruption Analysis feature from the Tools main menu. The following introductory page will appear:

When you click on the Next button, a progress dialog will appear showing you how far into the analysis you are. busTRACE will notify you if any data corruption is detected. busTRACE will inform you of how many data corruption errors and warnings were detected.

If the analysis detected any errors or warnings, you will be given the option of copying the results to the clipboard or saving it to a file.

To assist you in analyzing corrupted I/O activity, any I/Os where corruption are detected will be automatically bookmarked. In addition, an informative comment will be attached to the I/O.

If busTRACE was unable to perform a full data corruption analysis, a warning may appear in the analysis report. Below is a description of some of the more common warnings.

WARNING: MDLs were not captured. This is likely caused by the user disabling the MDL capture feature. Data corruption analysis results may not be valid.

The user disabled the "Capture IRP MDL" setting. This can also occur if you read in a capture from a version of busTRACE prior to busTRACE 10.0. The data corruption analysis results may be invalid if you are testing I/O activity through the file system. If performing raw reads/writes, then the results should be valid.

busTRACE was not configured to capture the entire data transfer on one or more devices.

When you capture I/O activity, you can configure busTRACE to not capture all the data being transferred. In its default state, busTRACE captures up to 512 bytes of data transfer per I/O (2048 for CD/DVD devices). If you do not configure busTRACE to capture larger I/O activity, you are limiting busTRACE's ability to perform a reliable data corruption analysis. Under this condition, the previously cited warning would appear.

Enabling Automatic Data Corruption Analysis

You may find yourself wanting busTRACE to automatically perform a data corruption analysis each time you stop the capture process. To do so, select Options from the Tools main menu and click on the I/O Handling tab.

Simply place a checkmark next to the Perform automatic data corruption analysis when capture stops option. When enabled, busTRACE will automatically launch its data corruption analysis feature every time you stop the capture process. If no error or warning occurs during the analysis, all you will see on screen is a momentary progress indicator showing you the analysis progress.

See Also:

• Analyzing Captured I/O Activity