The CDB Exerciser is showing me more data transferred than what was truly transferred by the device. Why?
Some port/miniport drivers do not properly report the number of bytes transferred. This is often caused by a hardware limitation. For example, we may pass down a buffer size of 1024 bytes, but the device returns back 256 bytes. The port/miniport driver should return back that the device transferred 256 bytes. Instead, it might report back the full length of 1024 bytes. We have put in special handlers to attempt to detect this situation and display only the data that is transferred in the CDB window. However, our workaround is not possible with all commands. This problem is common when the device is an ATAPI device, and DMA mode is enabled. To assist you in discovering this issue, we fill the buffer with the value CCh before issuing the command. The Raw Data window will always show you the data transferred as reported back to us from the port/miniport driver.
