Patrick put Ubuntu Linux on his 2007 iMac recently. But he has to fiddle with the audio some to get it to sound good. Leo says that isn't uncommon and is probably a driver issue.
He's been using SuperDuper to boot from an external hard drive, but it now says he doesn't have permission to do it. Leo says that SuperDuper will work fine for the Mac partition but is getting confused with the Linux partition. SuperDuper will backup your permissions for Mac, but you may need to do the Linux permissions separately. SuperDuper may be modifying the ownership as it does backup. Here are a few ideas for Linux Command: type CHMOD will change permissions. CHOWN will change the ownership of a given file. MAN is a command that will teach you what each command will do. Or you can google the command and learn just about anything about Linux.