For a few months now, I've started seeing this, too. Never happened before on the same server.Linked to a kernel upgrade, perhaps? Linux 2.6.16.19, up 121 days, so the kernel is 4 months old. Hmm, can be the time of first seeing this, dunno. (AMD Athlon MP, IDE-ATA, but I doubt that it matters.)
Cheers, Luna Kid