Inside Macintosh: More Macintosh Toolbox /

Chapter 9 - Desktop Manager

About the Desktop Database

In earlier versions of system software, Finder information for each volume was stored in the volume's Desktop file, a resource file created and used by the Finder and invisible to the user. This strategy meets the needs of a single-user system with reasonably small volumes. The Desktop file is still used on ejectable volumes with a capacity less than 2 MB so that these floppy disks can be shared with Macintosh computers running earlier versions of system software. (Note, however, that resources can't be shared. Since the Finder is always running in System 7, it keeps each floppy disk's Desktop file open, so your application can't read or write to it.)

Because resources can't be shared, a different strategy has been used for AppleShare volumes, which are available to multiple users over a network. The Desktop Manager in System 7 uses the strategy for large local volumes that AppleShare file servers have previously used for shared volumes. When a volume is first mounted, the Finder collects the bundle information from all applications on the disk and builds the desktop database. Whenever an application is added to or removed from the disk, the Finder updates the desktop database. Through Desktop Manager routines, the database is also accessible to any other application running on the system.