I run a network of machines each having 4 hard drives. Most are installed as JBOD (just a bunch of disks), but some are installed as RAID, where / is on a RAID1 device. After upgrading to 11.10, the RAID machines display a blank screen right at the beginning of the boot process and stop there - most of the time. The system does respond to Ctrl+Alt+Del at that state, and, every once in a while after many successive reboots, the system does boot successfully. I tested this on two different hardware configurations (nVidia chipset and Intel chipset) and with both 64- and 32-bit Ubuntu with no difference in results. The JBOD machines do not suffer from this issue.
Any suggestions are appreciated.