8. Another holdover from the days of the disk is the C-key start-up This was used to start up from a bootable disk. But I also use it to start from a thumb drive I have with OS X installed - useful for rescue. I expect this will be used when the new Disk Warriors on a USB drive arrives, developed because new Mac no longer have disk drives for those Macs with disk, starting up with the mouse (Or track pad) key pressed will eject a disk. That also works with an Eject key or F12.