Maintaining consistency is an issue. In many cases, though, the external attributes are generally extractable from the file content itself, so you can do a reb

Maintaining consistency is an issue. In many cases, though, the external attributes are generally extractable from the file content itself, so you can do a rebuild if the data gets corrupted. The BeOS mail application used the extended attributes extensively. Its mail store was basically a bunch of flat files containing the messages (perhaps in folders corresponding to the mail folders), and the extended attributes were used to index the date, sender, etc. These indices were then used to generate mail views, respond to searches, etc. - the mail app could effectively be a custom file system browser that used the extended attributes to speed itself up and quickly access and search mail metadata.