[CentOS] Hard drive errors

One of my CentOS boxes has started giving me errors.  The box is
CentOS-4.4 (i386) fully updated.  It has a pair of SATA drives in a
software raid 1 configuration.

The errors I see are:

    ata1: command 0xca timeout, stat 0x50 host_stat 0x24
    ata1: status=0x50 { DriveReady SeekComplete }
    Info fld=0x1e22b8, Current sda: sense key No Sense
    ata2: command 0xca timeout, stat 0x50 host_stat 0x24
    ata2: status=0x50 { DriveReady SeekComplete }
    Info fld=0x1e2598, Current sdb: sense key No Sense

If it was just coming from one drive, I would say it was a bad drive,
but this is happening on both drives.

Can anyone give me a starting place to diagnose this?

Thanks.

--
Bowie