The WLK 1.2 version of the optical logo test would need at least two identical test drives to validate if the drive reports unique serial number. If the test drive is a Read only drive then it would need two identical test drives and one writable drive. The writable drive is to burn test data for verifying the read functionality of the read only test drive.
The optical logo test verifies if the identical test drives report unique serial numbers. But there is a test issue that would cause the test case to fail. The test case failures are covered by the following erratas.
Filter ID: 1254
Filter ID: 1255
This test case would be fixed for the next release of the WLK.