Adjacent Track Interference test evaluates the effect of multiple writing of a track onto the neighboring tracks. The test measures the change of TAA, SNR, and BER values after writing the adjacent tracks.

The test uses the Servo Position Error Signal (PES) to prevent writing the sectors, where the Servo PES signal exceeds a user-specified tolerance. The test subsequently retries writing in those “skipped” sectors until the requested number of writes is performed in each sector. The improved WATI 2 test uses a new algorithm of retires in order to perform writing faster.

For example, if PES in tolerance probability of a single write operation is 70% and you would like to make 1000 write operations achieving 50% succeeded sectors:

the original WATI test performs approximately 7000 write operations,
the new WATI 2 test requires approximately 1400 write operations.

test time comparison

Figure 1. Test Time Comparison between Original WATI and WATI 2

The WATI 2 test is only available for RWA-2000 series equipped with RWA Control 2 board (Guzik P/N 325800). If your RWA has the older RWA Control board (Guzik P/N 306180), and you would like to use the new WATI mode, please contact sales@www.guzik.com for upgrade. Please send us the RWA EEPROM Dump with your request.

Improved Adjacent Track Interference Test (WATI 2)

Figure 1. Test Time Comparison between Original WATI and WATI 2