System Folder
Encyclopedia
The System Folder is the directory in classic versions of Mac OS
(those prior to OS X
) that holds various files required for the system to operate, such as font
s, system extensions, control panels, and preferences.
Note: On Mac OS X, files in /Library are not loaded at boot time when booting into Safe Mode.
in the filesystem hierarchy, but does not need to be. The Mac OS identifies the "System Folder" by undocumented characteristics that are independent of its name (it has different names in non-English versions of the Mac OS), or its location in the directory hierarchy. The Macintosh Finder
displays this "blessed" folder with a special icon. A "live" System Folder can freely be moved to any location in the directory hierarchy while the OS is operating, and it will continue to operate with no problems after the folder has been moved and after the system is restarted with the folder in its new location.
When the Finder copies a "blessed" folder to a new volume, the copy is "blessed" as well. On a system with more than one disk volume, it is thus easy to create functioning backups of a system simply by dragging the folder. It is also easy to maintain older and newer versions of the OS "in parallel", each on its own volume, and revert to the old one if problems are encountered with the new one.
This degree of flexibility distinguishes the classic Mac OS from most other operating systems, including Mac OS X.
All versions of Mac OS permit multiple copies of the operating system on a single volume. Mac OS 9
added formal support for this by permitting the user to select from multiple copies of the system on the same volume via the Startup Disk control panel, primarily used for selecting which volume to boot from.
Prior to this, one would have to manually bless the copy of the System Folder that they wished to use. A folder can be de-blessed by removing either the System or Finder files from it, which are the two files required for booting. (New World Macintoshes also need the Mac OS ROM file.) Some versions of Mac OS, 8.5
and upwards included (but not X
), check the blessed System Folder before shutdown and warn the user if the System Folder is missing any of the key system files, to prevent them from inadvertently rendering the hard drive unbootable. An alternative to manually blessing the system folders in the Mac OS was to use a utility like System Picker
.
, are controlled by adding or removing items from folders in the System Folder.
This process was made more convenient when Apple implemented the Extensions Manager
, itself a Control Panel that was originally a shareware utility by Ricardo Batista. This allowed activation and deactivation of Control Panels, Extensions, Startup Items and Shutdown Items, and could be invoked fairly early in the boot process by holding down the space bar on the keyboard.
One notable absence was the managements of Fonts. For this, Apple allowed Third-party development of font management programs
such as Extensis
Suitcase, Adobe Type Manager and AlSoft MasterJuggler.
Mac OS
Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...
(those prior to OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
) that holds various files required for the system to operate, such as font
Typeface
In typography, a typeface is the artistic representation or interpretation of characters; it is the way the type looks. Each type is designed and there are thousands of different typefaces in existence, with new ones being developed constantly....
s, system extensions, control panels, and preferences.
| System Folder location | Mac OS X equivalent | Description |
|---|---|---|
| Extensions | /System/Library/Extensions /Library/Extensions |
Classic Mac: Stores OS extensions (init format) Mac OS X: Stores kernel extensions and drivers (kext format) |
| Startup Items | /System/Library/StartupItems /Library/StartupItems |
Stores files or scripts to be executed at boot time. |
| Control Panels | /System/Library/PreferencePanes /Library/PreferencePanes |
Classic Mac: Stores system configuration programs, which are loaded at boot time. Mac OS X: Stores the various properties that appear in System Preferences. |
| Preferences | /Library/Preferences | Stores various application and system preferences. |
Note: On Mac OS X, files in /Library are not loaded at boot time when booting into Safe Mode.
Location and "blessed" folders
It is normally located directly below the root directoryRoot directory
In computer file systems, the root directory is the first or top-most directory in a hierarchy. It can be likened to the root of a tree — the starting point where all branches originate.-Metaphor:...
in the filesystem hierarchy, but does not need to be. The Mac OS identifies the "System Folder" by undocumented characteristics that are independent of its name (it has different names in non-English versions of the Mac OS), or its location in the directory hierarchy. The Macintosh Finder
Macintosh Finder
The Finder is the default file manager used on Mac OS and Mac OS X operating systems; it is responsible for the overall user-management of files, disks, network volumes and the launching of other applications...
displays this "blessed" folder with a special icon. A "live" System Folder can freely be moved to any location in the directory hierarchy while the OS is operating, and it will continue to operate with no problems after the folder has been moved and after the system is restarted with the folder in its new location.
When the Finder copies a "blessed" folder to a new volume, the copy is "blessed" as well. On a system with more than one disk volume, it is thus easy to create functioning backups of a system simply by dragging the folder. It is also easy to maintain older and newer versions of the OS "in parallel", each on its own volume, and revert to the old one if problems are encountered with the new one.
This degree of flexibility distinguishes the classic Mac OS from most other operating systems, including Mac OS X.
All versions of Mac OS permit multiple copies of the operating system on a single volume. Mac OS 9
Mac OS 9
Mac OS 9 is the final major release of Apple's Mac OS before the launch of Mac OS X. Introduced on October 23, 1999, Apple positioned it as "The Best Internet Operating System Ever," highlighting Sherlock 2's Internet search capabilities, integration with Apple's free online services known as...
added formal support for this by permitting the user to select from multiple copies of the system on the same volume via the Startup Disk control panel, primarily used for selecting which volume to boot from.
Prior to this, one would have to manually bless the copy of the System Folder that they wished to use. A folder can be de-blessed by removing either the System or Finder files from it, which are the two files required for booting. (New World Macintoshes also need the Mac OS ROM file.) Some versions of Mac OS, 8.5
Mac OS 8
Mac OS 8 is an operating system that was released by Apple Computer on July 26, 1997. It represented the largest overhaul of the Mac OS since the release of System 7, some six years previously. It puts more emphasis on color than previous operating systems...
and upwards included (but not X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
), check the blessed System Folder before shutdown and warn the user if the System Folder is missing any of the key system files, to prevent them from inadvertently rendering the hard drive unbootable. An alternative to manually blessing the system folders in the Mac OS was to use a utility like System Picker
System Picker
System Picker is a freeware Classic Mac OS utility that allows the blessing of several System Folders. It was designed for System 6 and System 7, but is confirmed to work on Mac OS 8. It allows for multiple System Folders to be present on the same drive, working around the limitations of the...
.
User accessibility and customization
The System Folder is less protected than the Mac OS X system folder, in that the contents are all viewable and most files and folders are editable. However it was possible to prevent inexperienced users from accidentally altering the contents by using the Protect System Folder Contents checkbox in the General Controls Control Panel. The Startup and Shut Down programs, Appearance themes, control panels, fonts, and extensions, as well as items in the Apple MenuApple menu
The Apple menu has been a feature in Apple's Mac OS since its inception. It is the first item on the left hand side of the menu bar. The Apple menu's role has changed throughout the release history of Mac OS, but the menu has always featured a version of the Apple logo.-System 6 and earlier:In...
, are controlled by adding or removing items from folders in the System Folder.
This process was made more convenient when Apple implemented the Extensions Manager
Extension conflict
Extension conflicts were sometimes a problem on Apple Macintosh computers running versions of Mac OS prior to X, especially System 7. Extensions were bundles of code that extended the operating system's capabilities by directly patching OS calls, thus receiving control instead of the operating...
, itself a Control Panel that was originally a shareware utility by Ricardo Batista. This allowed activation and deactivation of Control Panels, Extensions, Startup Items and Shutdown Items, and could be invoked fairly early in the boot process by holding down the space bar on the keyboard.
One notable absence was the managements of Fonts. For this, Apple allowed Third-party development of font management programs
Font-management program
Font management software is utility software that computer users use to browse and preview fonts and typically to install and uninstall fonts. In addition, depending on the individual font management program's capabilities, users can also...
such as Extensis
Extensis
Extensis is a software company based in Portland, Oregon. Its three main products are Extensis Portfolio, Suitcase Fusion, and Universal Type Server....
Suitcase, Adobe Type Manager and AlSoft MasterJuggler.