This is a collection of the (poorly documented) key-sequences that do things. It’s probably possible to find all this information within Apple’s Knowledge Base, but it’s currently scattered across multiple entries. In any case, this came from a number of smart people, but Marc Pawliger started the list and Tim Hume collected the various responses. Miro, Andy, Darin, Chris, Barry, the other Marc, Greg, Jon and Ned offered clarifications. I just turned it into a web-page.
It’s pretty sad that there are so many “hidden” things in an OS that’s supposed to be so easy to use. I hadn’t thought about it before, but the sheer volume of them has surprised me. I knew of the existence of a lot of these shortcuts myself, but I’d never tried to think of them all at once until I started compiling this page. Now that I have many of them in one place (there’s more to be added – I think there always will be), I find myself wondering about ease of use. Anyway, enjoy.
Eject removable media ( I think Boot ROMs prior to 2.4f1 excluded the CD drive )
Bring up OF system picker on New World machines – boot to 9 on pre-New World machines
Bring up Mac OS X boot partition selector (DTKs only?)
When OF system picker is active, open the CD tray
Hold down until 2nd chime, will boot into Mac OS 9 ?
cmd-x (or just x?)
Will boot into Mac OS X if 9 and X are on the same partition and that’s the partition you’re booting from.
prevent native drivers from loading (System 7 until 9.x?)
Bypass startup drive and boot from external (or CD). This actually forces the system to NOT load the driver for the default volume, which has the side effect mentioned above. For SCSI devices it searches from highest ID to lowest for a partition with a bootable system. Not sure about IDE drives.
Boot from a specific SCSI ID # (# = SCSI ID number)
Zap PRAM. Hold down until second chime.
Clear NV RAM. Similar to reset-all in Open Firmware.
Boot into open firmware
Force Quadra AV machines to use TV as a monitor
Boot from ROM (Mac Classic only)
Force an AV monitor to be recognized as one
Boot from CD. If set to boot to X and no CD is present, may boot to 9.
Force the internal hard disk to be the startup device
Hold down until Mac logo, will attempt to boot from network server (using BOOTP or TFTP)
Force PowerBooks to reset the screen
Put FireWire machine into FireWire Target Disk mode
Attempt to boot using the devalias zip from first bootable partition found
Reset power manager (with computer off)
(Classic only) Disable Extensions
(OS X, 10.1.3 and later) Disables login items. Also disables non-essential kernel extensions (safe boot mode)
(Classic only) Boot with Virtual Memory off
(OS X only) show console messages (verbose mose) during boot. Also invokes Safe Mode
(OS X only) boot into single user mode
(Mac IIci only) Set date to 20 Sep 1989 to get a graphical easter egg
(Mac IIfx only) Set date to 19 Mar 1990 to get a graphical easter egg
Erase startup disk under 7.1(?)
After display of Happy Mac icon
(Classic only) Invoke Extensions Manager
(Classic only) Disable Extensions including MacsBug