Have a WD2500SD-01KCB0 drive hooked up to an Adaptec HostRAID SATA2 1420 controller.  Drive is still in warranty.

Log Name:      System
Source:        disk
Event ID:      11
Level:         Error
Keywords:      Classic
Description:
The driver detected a controller error on \Device\Harddisk2\DR2.

Log Name:      System
Source:        aar81xx
Event ID:      15
Level:         Error
Keywords:      Classic
Description:
The device, \Device\Scsi\aar81xx1, is not ready for access yet.

Replaced cable and put another drive in this system.  Put drive into another machine, and running diagnostics now.  SMART tests are fine... but when are they not? =)

More later...