Niall, You obviously missed a cue when planning your database. It should have been created with a 32k blocksize, allowing 2070 extents in your database. ;) Seriously though, I don't understand the purpose of table 7-6 at all. Was this doc written April 1st? Jared ----------------- On the other hand it has had some nice howlers in there from time to time. My favourite reason for running oracle on unix is that according to the 9i documentation there is a limit on the number of extents for *the database* of (assuming an 8k block size) 504. http://tinyurl.com/2l5ye refers. Not sure how the data dictionary gets created since I have more than 504 segments owned by sys in my 9.2 database, so I'd have to fit several segments in the same extent not even all segments should fity in 1 extent works :( - Niall Litchfield Oracle DBA