Jag's World Header




Mad With Macintosh


What's In The Sytstem Folder?

This article gives brief descriptions of the files and folders you'll find in

the System Folder of a Macintosh computer installed with system software

version 7.0. The article indicates how the 7.1 System Folder differs.


DISCUSSION ------------------------------------------------------


System Software


The Macintosh stores system software in two types of memory: Read Only

Memory (ROM) and Random Access Memory (RAM). Sections of the operating system

are contained permanently in ROM. This type of system software, which is built

into the hardware, is called firmware.

The system software that you install provides updates (new routines and

corrected versions of old routines) between major ROM revisions. These updates

are provided in System and Finder files, device drivers, and other resources

found in the System Folder. When a system boots up, it loads the data from the

System Folder and places the data in RAM, where it's stored until you shut down

the system.


System Folder


You can't open many of the files in the System Folder because most of them

are resource files, not applications. Their use is restricted to the system.

But you can remove or copy them, and you can add files to the System Folder.

The exact content of a System Folder depends on the Macintosh model and other

equipment used with the Macintosh. At the top level, the System Folder

generally contains these items:


* The System file


* The Finder file


* The System Enabler (System 7.1)


* Clipboard file


* Note Pad File


* Scrapbook File


* Apple Menu Items folder


* Control Panels folder


* Extensions folder


* Fonts folder (System 7.1)


* Preferences folder


* PrintMonitor Documents folder


* Startup Items folder



The following sections describe the top-level files in the System Folder.


System File


This is the most important file on a startup volume, and it's the first file

loaded during the boot process. It contains the RAM-based portions of the Mac

ToolBox and operating system, ROM extensions and patches, fonts, and sounds.

All applications and the operating system share the System file's collection of

resources. Every Macintosh startup disk requires this file to start up and run

the Macintosh computer.


Finder File


The Finder is the application that presents and maintains the Macintosh

desktop. The Finder keeps track of what files belong in which folders and

where they appear on the desktop. It manages disks and files, and it launches

other programs. Every Macintosh startup disk requires this file to start up

and run the Macintosh computer.

Ordinarily, the operating system designates the Finder as the startup

application. This means it's the application that takes control when you first

start the system. With System 7, the Finder stays open while you're running

other applications.


System Enabler


All new Macintosh models shipping after the release of version 7.1 include a

System Enabler specific for that model or a particular family of models, like

the Macintosh PowerBook family. System Enablers provide compatibility between

Macintosh CPU hardware and system software. You add a System Enabler rather

than reinstalling a new system. System Enablers are located at the top level

of the System Folder -- not in the Extensions folder.


Clipboard File


The Clipboard stores data that you have cut or copied.


Notepad File


The Notepad desk accessory uses resources found in this file.


Scrapbook File


This file stores graphics and text for the Scrapbook desk accessory. The

Scrapbook retains information even after the system shuts down.

Note: If you delete the Clipboard, Notepad, or Scrapbook files, the system

will recreate them.


Apple Menu Items Folder


You install files in the Apple menu by dragging them into the Apple Menu

Items folder. You can put any file or alias that opens when double-clicked

(applications, documents, server volumes) in the Apple menu. When you install

System 7, the Alarm Clock, Calculator, Chooser, Key Caps, and Scrapbook desk

accessories and a Control Panels folder alias appear in the Apple menu.


Control Panels Folder


The Control Panels folder contains resources that allow you to set features

for your computer. The system draws upon data and instructions provided in

these control panel files, sometimes called Control Panel Device Resource files

(cdev files). The specific control files included with the Macintosh system

depends on configuration requirements and user preferences. Here are some of

the control panels you may find in this folder:


* Color

If you have a color monitor, the Color control panel lets you select

highlight and window colors.


* Date & Time

This control panel allows setting the computer system date and time.


* Easy Access

Easy Access supports features the Macintosh provides for disabled people:


* Mouse Keys - a substitute for using the mouse


* Sticky Keys - a way to input complex key sequences more easily


* Slow Keys


* File Sharing Monitor

The File Sharing Monitor control panel lets you observe file sharing

activity. It shows you the name of any connected users, and it lets you

disconnect any connected users.


* General Controls

This control panel allows changing features like desktop pattern and rate of

insertion point blinking.


* Keyboard

This lets you select keyboard layout, and key repeat and delay rates.


* Labels

The Labels control panel provides the colors and names for the Finder Label

menu. You can change the label names and colors corresponding to the label



* Map

The Map control panel lets you type in a city name to see geographic

location information.


* Memory

This is where you set the disk cache size, and turn on or off virtual memory

and 32-bit addressing.


* Monitors

The Monitors control panel is where you select monitor characteristics

(number of grays or colors). You can also set monitor orientation when you have

more than one monitor connected to your computer.


* Mouse

The Mouse control panel lets you select tracking and double-click speeds for

your Mouse device.


* Network

The Network control panel shows the available data links (LocalTalk,

EtherTalk, TokenTalk). These resources are called AppleTalk Devices (adev

files). You select which data link to use for network operations. Switching

data links causes a temporary loss of network connections.


* Numbers

Here is where you set number display format.


* Sharing Setup

In this control panel you can start File Sharing or Program Linking. And you

enter information here to identify your computer on the network.


* Sound

This is for specifying the type and volume of sound for your computer.


* Startup Disk

If you have more than one volume attached to your computer, you can specify

the startup disk in this control panel.


* Token Ring

This is used to set transmission speed of the Apple Token Ring 4/16 NB

card, to set other operational timers, and to assign a locally administered

address used for network management instead of the default hardware address.


* Users & Groups

This control panel allows you to designate who has access privileges to your



* Views

Here you select the font, icon arrangement, and list information shown on

the desktop.


Extensions Folder


The Extensions folder contains:


* System extensions, called INITs in System 6 (for example, network drivers)


* Chooser extensions, sometimes called Remote Devices (rdev files) (for

example, AppleShare, CD-ROM, and printer drivers)


* System applications (for example, PrintMonitor)


* PostScript fonts


When you start your computer, the Extensions folder is the first place the

system looks when loading system extensions.


Printer Software


Printer drivers, sometimes called printer resources, provide the interface

to specific printers. You indicate your choice of printers in the Chooser.

When you select a printer with the Chooser, the system draws upon the resources

in these files. A system must have the resource files corresponding to the

printers used with the system.

Here's a list of some printer drivers included with system software version



* AppleTalk ImageWriter


* ImageWriter


* LaserWriter

This is for all LaserWriter printers except the LaserWriter Pro series.


* LQ AppleTalk ImageWriter


* LQ ImageWriter


* Personal LaserWriter SC


* Personal LW LS


* StyleWriter


* Laser Prep

LaserWriter driver versions 6.0 and earlier, and AppleShare Print Server 2.0

require the Laser Prep file. This file works with the LaserWriter driver to

provide PostScript, the language the LaserWriter uses to print text and

graphics. The Laser Prep file is rolled into LaserWriter driver version 6.1

and later.


* Printer Share

Printer Share is part of GrayShare, and the extension allows sharing

StyleWriter II, Apple Color Printer, LaserWriter Select 300, and Personal

LaserWriter 300 printers.




Other Chooser Extensions


If you have a CD-ROM drive, you need the appropriate software to access it,

like the Apple CD-ROM file. Foreign File Access handles the conversion of File

Manager calls to High Sierra or ISO 9660 discs.


Network Software


Network software provides the interface to network data links (for example,

EtherTalk, or TokenTalk).



A/ROSE stands for Apple Real-Time Operating System Environment. It's a

system extension that allows communication between the Macintosh main logic

board and Macintosh Coprocessor Platform (MCP) based NuBus cards that run the

Apple Real-Time Operating System.

A/ROSE runs as a driver under the standard Macintosh operating system. It

downloads, starts, stops, sets priorities, and communicates with real-time

processes that run on any A/ROSE-compatible NuBus card.


* EtherTalk Phase 2

EtherTalk software allows communication with AppleTalk network services over

Ethernet networking interface cards and media.


* Network Extension

The Network control panel uses resources in this extension.


* TokenTalk Phase 2

TokenTalk software allows communication with AppleTalk network services over

Token Ring networking interface cards and media.


* File Sharing Extension

This allows other users on a network to see information you designate for





This application runs in the background to send spooled information to the

printer. When printing is complete, PrintMonitor empties the PrintMonitor

Documents folder. System 6 also requires Backgrounder for background printing.


Fonts Folder


If you install system software version 7.1, you'll have a Fonts Folder that

provides a single location for fonts, including TrueType, Adobe Type 1, and

bitmapped fonts. System software earlier than version 7.1 stores TrueType and

bitmapped fonts in the System file.


Preferences Folder


The Preferences Folder stores preference files that keep default or current

settings for programs. Examples include these preference files created by

Microsoft word processing applications: Word Settings, MsWorksPref, and Excel

Settings. It also contains dictionary and help files. System 7-compatible

applications create and maintain these files automatically.


PrintMonitor Documents Folder


From your Macintosh computer, you can print to a LaserWriter or a

StyleWriter printer while you do other work. For instance, you can print and

continue working on a document at the same time. This is called "background


When you turn on background printing for printers in the Chooser,

PrintMonitor temporarily stores files waiting in the print queue in the

PrintMonitor Documents folder until the printer is ready to print them. This is

all done in the background.


Startup Items Folder


Place in this folder the aliases of all applications and documents that

you'd like to have opened automatically when you start up your Macintosh

computer. Don't put system extensions in this folder.


©1996-04 JagWerks Media