Today I had my HD103SJ just disappear from windows with no messages. Restarted and it was all there, nicely. But it got me worried and I got HD Tune to check on it. I get a "warning" at Ultra MDA CRC Count.
Changed the sata cable (and slot), but the numbers still appear there.
The SMART data is accumulative fixing the cause of the UDMA error won't reset the error count. If the count does not increase then you have fixed the problem. You won't get data corruption because of this error, the controller has detected the error and resent the correct data. If you get too many errors then it will slow down your transfer rate.