OIDs wraparaound: postgresql (different versions) behavior

The PostgreSQL manual explain that from 8.1 the default behavior
(governed by default_with_oids system parameter) is to create user
tables "without oids".

Well, at the page
http://www.postgresql.org/docs/8.1/interactive/datatype-oid.html , the
manual report this:
"Object identifiers (OIDs) are used internally by PostgreSQL as primary
keys for various system tables."

What do i look and take care about the OID wraparound phenomenon? (On a
DBA perspective)
There is a possibility for a data inconsistency? (Or possibles database
blocking errors?)
What's the differents server behaviors for this phenomenon on differents
realeases?

Thank in advance for replies.

Best regards,
Francesco.

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Francesco Dalla Ca'
Settore Gestione Sistemi CINECA
Via Magnanelli 6/3  40033 Casalecchio di Reno (BO)
Bologna, Italy             http://www.cineca.it
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