When there is a USB drive connected at boot time, the kernel displays the message "....HDIO_GET_IDENTITY failure...." before starting the X system which is only going to confuse and alarm users as it is basically useless and has no relevance to the actual operation of the system. I first noticed this on the Ubuntu 12.04 Alpha and subsequently Beta kernels, and confirmed it on the 3.3.0-rc6 kernel (which has additional diagnostic/debug messages). It just looks like someone has forgotten to comment out this bit of diagnostic code in the kernel package, or it is not placed correctly in the diagnostic code segments that are not compiled in the production kernels. This was originally reported at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/941271
The bug seems to be only apparent when a USB connected rotational drive does not support certain features when interrogated by the kernel at start-up, so for most drives it may not appear but for my tiny 8GB SEAGATE ST68022CF non-SMART drive they do. It still occurs on the 3.5.0-18-generic kernel on my Ubuntu 12.04 system.