freelists and dba_free_space

we are running Oracle 9.2.0.5 and I am fairly new at this DBA stuff. I need some clarification on space management.

1. Where can I see the number of available blocks (or bytes) from the freelist?
2. Is dba_free_space a view for the freelist?
3. When and how does the freelist get updated?
4. When and how does dba_free_space reflect blocks that become free?
5. within dba_tables what does the avg_row_len tell me? bytes, used columns, characters?

We just purged 2.5 million records from a table this weekend, and I can't seem to find that free space reflected anywhere. I guess I could see that possibly enough records from any one block were not removed to drop the blocks below pctused, I just don't think that is the case though. The data that was purged was data from 4 years ago, I would think it would have been located closely enough on the datafiles that quite a few blocks would have been freed.

Thanks for any info,
Ben Received on Mon Feb 13 2006 - 15:41:22 CST