Purpose

This quick reference guide is a compilation of some of the more useful keyboard shortcuts (outside of the normal operations) that can be invaluable to a technician while working on a Macintosh. It is important to note that most of them require Tiger or later distributions, and feel free to make adjustments to this list as their shortcuts change, or you make adjustments.

Symbol Guide

Name	Symbol	Abbreviation
Command		cmd
Control		cntrl
Shift		shft
Option		opt
Function	F	Fn
Escape		esc

Startup

Use these shortcuts while the system is still booting.

Key Command	Description
X	Force MacOSX Startup - useful in multi-boot systems
Option-Cmd-Shift-Del	Bypass primary start-up volume and seek a different startup volume (such as CD or External disk)
C	Start from CD that has system folder
N	Attempt a Network Boot
T	Start up in Firewire Target Disk Mode. Useful for data retrieval
Shift	Boot into Safe Mode and temporarily disable login items and non-essential kernel extensions

Zapping out the P-RAM

P-RAM is basically a place on the Mac where values and information is stored while the computer is powered down. In many bizarre cases PRAM has kept corrupt permissions or other strange artifacts from program outputs and caused problems. If you continually find yourself scratching your head trying to fix a computer, try zapping the P-RAM before throwing the book at it.

"Zapping PRAM" is a way of resetting PRAM back to its original factory values. The basic procedure is to hold down this key combination: Command-Option-P-R while powering on the Macintosh and waiting for the start-up sound. The latest recommendation from Apple requires holding down the keys until the start-up sound has repeated three more times. (Avoid holding down the power key too long because this reportedly triggers a problem on certain Macs, in which a ROM-based debugger dialog appears unexpectedly on the screen at a later time. You can type "G" to make the processor "Go" ahead from its suspended debugging state and continue operating normally.)

After resetting PRAM, check Chooser settings and Control Panels settings, including Color, Keyboard, Mouse, General Controls, Memory, Network, Sound and Startup Disk. With PowerBooks, check the various power-management options, too.

The most thorough, and most difficult, way to reset PRAM is by removing the computer's power cord and the battery on the motherboard that powers PRAM in the absence of normal power. Pushing the power switch a few times and waiting for a half-hour or more should flush everything out, including things you may prefer to retain, such as manufacture date, the number of power-on hours, and the date and time settings. (If the battery that backs up PRAM runs low, all sorts of bizarre problems can occur on the system, and the battery must be replaced. One typical symptom is that the Mac clock changes to strange values between the Mac's zero date of Jan. 1, 1904 and the current date.)

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