Apple Training Series: Mac OS X System Administration Reference, Volume 1

List some important differences between HFS Plus and UFS.

Is it safe to delete all of those dot files Windows users see when you save a file on a Windows file server?

What does diskarbitrationd do when you connect a USB storage device?

What is the main difference between an alias and a symbolic link?

What does the df command do?

HFS Plus is normally case-preserving but not case-sensitive. (A case-sensitive version is available.) HFS Plus provides native support for files with resource and data forks, and it is journaled by default on Mac OS X v10.3 and later. UFS is case-sensitive. It provides no native support for forked files. Journaling is not available for UFS.

No. Windows does not hide dot files the way most UNIX systems do. If the files are .DS_Store files, they are safe to delete as they contain only the icon position and other layout information for the Finder. However, resource fork shadow files (those that begin with ._) may not be safe to delete, as they may contain data belonging to the other half of that file.

diskarbitrationd probes the disk to determine its file-system format, checks the disk for unusable files, mounts the file system, and updates the disk arbitration table.

When you move the original file, the alias is updated to point to the new location. The symbolic link is not updated and is left dangling.

The df command displays disk capacity and the amount of free and available disk space on file systems.