- By Kevin M. White
- Dec 6, 2011
This chapter is from the book
- What are the four default top-level folders visible in the Finder?
- What are six common system resources? What purpose does each resource serve? Where are they located in the file hierarchy?
- What are the four system resource domains? What purpose does each domain serve?
- Why does the Finder hide certain folders at the root of the system volume?
- What two methods can be used to hide items from the Finder?
- What is file system metadata? What are some examples of file system metadata?
- What are some of the common file flags used by Lion?
- What does Lion use bundles or packages for?
- How does the system identify which application to open when a user double-clicks on a file?
- What are some privacy and security concerns with the Spotlight service?
- What are the differences between zip archives and disk images?
- How does the Spotlight search service use metadata?
- Where does Spotlight store its metadata index databases? How about the Spotlight plug-ins?
- What backup destinations does Time Machine support?
- How does Time Machine maintain a backup history of the file system?
- What types of files are omitted from Time Machine backups?
- Why is Time Machine inefficient at backing up large databases?
- Why might a previously backed-up item no longer be available in Time Machine?
- The four default top-level folders visible in the Finder are Applications, containing applications all local users have access to; Library, containing system resources all local users have access to; System, containing necessary system resources; and finally, Users, containing all the local user home folders.
- Six common system resources are extensions, which attach themselves to the system kernel to provide hardware and peripheral driver support; frameworks, which are shared code libraries that provide additional software resources for both applications and system processes; fonts; preference files, which contain application and system configuration information; LaunchAgents and LaunchDaemons, used by launchd to provide services that automatically start when they are needed or at system startup; and finally, logs, which are text files that contain error and progress entries from nearly any application or system service.
- The four system resource domains are User, containing applications and system resources specific to each user account; Local, containing applications and system resources available to all users on the local Mac; Network (optional), containing applications and system resources available to any Mac that has an automated network share; and finally, System, containing applications and system resources required to provide basic system functionality.
- The Finder hides traditional UNIX resources from average users because they don’t need to have access to those items. If users do need access to these UNIX items, they can access them from the Terminal.
- The Finder will not show items with periods at the beginning of their filename or items with the hidden file flag enabled.
- Metadata is information stored outside of a file or folder. It provides additional information about files and folders. Examples include file flags, extended file attributes, and permissions.
- Common file flags include the locked flag, which locks files from changes, and the hidden flag, which hides the item in the Finder.
- Bundles and packages are used to combine complex items into individual folders. Packages have the additional advantage of appearing as a single item in the Finder. This allows software developers to combine resources into a single item and prevents users from messing with those resources.
- Files are identified primarily by their filename extension. Launch Services maintains a database of known applications and which file types they can open. When you double-click on a file in the Finder, Launch Services tries to find an appropriate match. You can override the default application selection in the Finder.
- Though Spotlight indexes file and folder permissions, it will allow other users to search the contents of locally attached non-system volumes when ownership is ignored on those volumes.
- Zip archives are created with the Finder from a specific selection of items. Zip archives are compatible with many operating systems. On the other hand, disk images are made using Disk Utility and allow you to create highly flexible archive volumes that can contain nearly anything.
- The Spotlight search service creates index databases of file system metadata so that it can perform normally time-intensive searches nearly instantly.
- Spotlight metadata index databases are stored at the root of every volume in a /.Spotlight-V100 folder. However, a Legacy FileVault user’s database is stored in his encrypted home folder. Also, the Mail application maintains its own database in each user’s home folder at ~/Library/Mail/V2/MailData/Envelope Index. Spotlight plug-ins can be located in any Library in a folder named Spotlight.
- Time Machine can back up to any Mac OS Extended volume, or network shares hosted from Time Capsule or a Mac OS X Server.
- Time Machine starts with a full copy of the file system; then it records any changes to the file system, and only copies the changes. It creates a simulation of the full file system using hard links for files that have not changed.
- Time Machine always ignores temporary files, Spotlight indexes, items in the Trash, and anything else that can be considered a cache. Time Machine will also ignore any files an application has defined as exempt, or any files you have defined as exempt in the Time Machine preferences.
- Time Machine is inefficient at backing up large databases because it must back up the entire database file every time any change, no matter how small, is made to the database.
- A previously backed-up item will not be available if your backup volume has become full and Time Machine has had to start deleting older items to make room for newer items.