kernel errors

From: Matt Keys 
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I've seen strange errors appear in syslog for a few months but I don't 
know if it's just regular noise .. :

kernel: [323132.131302] ata2: SError: { UnrecovData Handshk }

kernel: [323132.138825] ata2.00: failed command: WRITE FPDMA QUEUED

kernel: [323132.146351]          res 40/00:04:78:7d:1f/00:00:20:00:00/40 
Emask 0x10 (ATA bus error)

kernel: [320393.074209] ata4.00: irq