While (so far unsuccessfully, see #216324) booting of the 2008.0 beta1 LiveCD any attempt to go into a shell by typing "shell" at the root block device prompt results in every character being typed appearing twice on the command-line. This is not a keyboard problem, as it works fine when I boot SystemRescueCD-1.0.1 or Vista. It's one of those cheap USB keyboards that comes standard with Dell systems. A tip on the Ubuntu forums (http://ubuntuforums.org/showthread.php?t=535341) to add noapic irqpoll acpi=force during boot did not help.
root@sysresccd /root % lsusb Bus 007 Device 001: ID 0000:0000 Bus 003 Device 001: ID 0000:0000 Bus 008 Device 001: ID 0000:0000 Bus 006 Device 001: ID 0000:0000 Bus 005 Device 003: ID 413c:3012 Dell Computer Corp. Bus 005 Device 002: ID 413c:2003 Dell Computer Corp. Keyboard Bus 005 Device 001: ID 0000:0000 Bus 002 Device 002: ID 0644:0200 TEAC Corp. Bus 002 Device 001: ID 0000:0000 Bus 004 Device 001: ID 0000:0000 Bus 001 Device 001: ID 0000:0000
Based on the discussion in http://forums.gentoo.org/viewtopic-t-577952.html I changed a BIOS setting related to the SATA mode, and the keyboard problem is now gone. Just like in the thread, this was with a Dell Inspiron 530.
Then I guess this isn't an issue with our media :P
Well, when the SATA mode was in "IDE" SystemRescueCD booted without keyboard problems while the Gentoo LiveCD had the double characters, so I guess there was *something* going on. Switching the SATA mode at least made the problem go away for me...
Come to think of it, the problem might have been that after Grub had done its thing and loading of the kernel had started my CD-player could not be found anymore (solved by switching SATA mode) so the boot-procedure halted. Perhaps it halted before the relevant keyboard driver could be loaded.