Hi Juan, Well, the word "internals", to me, means stuff that's not documented. As such, there is no official source. The people who are the official source have specifically decided to NOT officially provide information on "internals". As there is no official source, gathering information on internals is a bit haphazard at best. My primary sources of internals info are: 1.) Oracle 8i Internal Services, aka, "The Steve Adams book". I=20 think it's fair to say this is the single best source of internals=20 info available. 2.) http://www.ixora.com.au , aka, "The Steve Adams Website". I think it's fair to say this is the single second best source of internals info = available. 3.) Interesting info can sometimes be found on Google, given the = correct search terms. Not reliable, but sometimes fruitful. 4.) Various MetaLink documents sometimes touch on internals = information. There's no way to know which ones, you just have to stumble across it. 5.) Asking the right question, in the right forum, with the right=20 participants, may yield some useful info. But the best way to grow the knowledge base of Oracle internals is to=20 investigate. Set up tests and experiments with clearly defined=20 boundary conditions, and what results you expect. Run your test. Publish your results. -Mark -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Juan Carlos Reyes Pacheco Sent: Thursday, September 16, 2004 9:07 AM To: oracle-l@xxxxxxxxxxxxx Subject: official source for Oracle internals Hi list,=20 Which is the official source for Oracle Internals, Metalink, SYS schema = try and test, Oracle University, experts, Tom Kyte, google. If one day someone decide to learn them and update, which is the first = place he should go. Thanks in Advance =20 Juan Carlos Reyes Pacheco OCP -- //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l