From: Apgar@Apple.com (Gar)
Newsgroups: comp.sys.mac.system
Subject: Re: How do you zap PRAM under Sys7?
Date: 21 Aug 92 01:41:45 GMT
Followup-To: comp.sys.mac.system
Organization: Apple

In article <22521@sybase.sybase.com>, bill@kirkwood.sybase.com (Bill
McFarland) wrote:
> 
> What is parameter RAM, why would one "zap" it (what does "zap" mean?), how
> do you know if you need to zap it?


With the exception of Date and Time, all system-wide preferences are reset
to
default values by zapping parameter RAM (PRAM).  To zap PRAM under System
7,
hold down the Command-Option-p-r keys during startup (Make sure the Caps 
Lock key is up!).  The Macintosh will restart shortly after displaying the
"Welcome to Macintosh" screen, which indicates that PRAM has been reset. 
The Date and Time settings are actually read out of PRAM before it is
zapped, 
then written back in afterwards. Note that if a MacintoshUs battery is 
drained, the date and time are reset to the default value (12:00 am, 
January 1, 1904) after each startup.

System Preferences Stored in PRAM
---------------------------------
The following are system-wide preferences that may affect all applications:
* 32-bit Addressing (Memory Control Panel)
  (default: 24-bit addressing)
* Brightness settings (Brightness Control Panel)
  (default: mid-range on the slider)
* Highlight Color (Color Control Panel)
  (default: black)
* Cursor blink rate (General Control Panel)
  (default: middle setting)
* Menu blink count (General Control Panel)
  (default: 3 times)
* Date, Time and displayed format (General Control Panel and Alarm DA)
  (default: 12:00 am, January 1, 1904)
* Keyboard Repeat Rate and Repeat Delay (Keyboard Control Panel)
  (default for repeat: one away from Fast)
  (default for delay: one away from Long)
* Disk Cache size (Memory Control Panel)
  (default: 16K)
* Monitor Settings and Location of extra monitors (Monitors Control Panel)
  (default: primary monitor only, set to Black & White)
* Mouse Tracking and Double-click Speeds (Mouse Control Panel)
  (default for tracking: Very Slow)
  (default for double-click: Middle setting)
* Beep Sound (Sound Control Panel)
  (default: Simple Beep, even though it is not highlighted)
* Startup Disk Choice (Startup Disk Control Panel)
  (default: none set, will use standard volume search method)
* Default application font is reset to Geneva.
* Serial port speeds for printer and modem ports are reset to 9600 bps.
* AppleTalk active/inactive (Chooser)
  (default: AppleTalk is active.)
* Selected network (Network control panel)
  (default: Built-in LocalTalk port is selected)
* Macintosh IIfx serial port (IIfx Serial Switch Control Panel)
  (default: Faster is selected)
* Macintosh Quadra 68040 CPU cache (Cache Switch Control Panel)
  (default: Faster is selected)
* Macintosh Portable speaker is reset to more audible volume.
* Macintosh Quadra/Powerbook RAM Disk (RAM Disk Control Panel)
  (default: RAM disk is off, size is set to 192K)

Finder Preferences
------------------
The following are Finder-specific preferences (Note that some preferences
affecting portions of the user interface extend to other applications, 
such as window title shading.):
* Font used for Finder views (Views Control Panel)
  (default: Geneva 9)
* Icon Alignment Settings for Finder (Views Control Panel)
  (default: straight grid, "Always snap to grid" deselected)
* Icon List View Settings for Finder (Views Control Panel)
  (default: smallest icon; display sizes, kinds, labels, and dates;
  Deselect "Calculate Folder Sizes" and "Show Disk Info in Header")
* Trash Can warning dialog (setting in Get Info for the Trash Can)
  (default: warn before emptying)

With the exception of virtual memory, these parameters may be reset by 
deleting the Finder  Preferences file, which is located in the Preferences 
folder inside the System Folder.  Since System  7 will not allow this 
file to be modified if it is on the startup disk, you will need to disable 
it  instead.  To do this, drag the Finder Preferences file out of the 
Preferences folder and restart the Macintosh.  System 7 will create a 
new Finder Preferences with default values automatically.   You may 
then delete the old Finder Preferences file.

NOTE: The Virtual Memory, File Sharing and Window Color settings are 
stored with their respective Control Panel files and cannot be reset 
using these methods.  Virtual Memory and File Sharing can be temporarily 
disabled, however, by pressing the Shift Key while starting the Macintosh 
Hold the key down until "Extensions Off" appears in the "Welcome to
Macintosh" 
screen.

Apgar@Apple.com                   I said it, NOT Apple.