I try to kill cdrecord; but it doesn't respond (my guess is that it's stuck in kernel mode waiting on a response from the dvd burner; so the kernel won't send it the signal until it leaves kernel mode (total guess)).
The noise is making me very sad; so I bite the bullet: Alt + SysRq + s (force-sync filesystem); Alt + SysRq + r (I thought it was reboot. Instead it does something with the keyboard: "Turns off keyboard raw mode and sets it to XLATE.").
So, after fighting with the keyboard for a minute (yay Alt + SysRq + r); I open the doc that contains all of the keys and what they do; tail /var/log/messages for good measure; sync a few more times; then Alt + SysRq + b (reBoot; of course).
So once the system rebooted I could eject the tray to see what was wrong... I accidentally dropped in two discs instead of one; I was hearing one slide under the other.
And reading sysrq.txt now it tells me that I should have done Alt + SysRq + u ("Unmount" --> Remount all filesystems read-only) after sync and before boot.
