[QUOTE][i]Originally posted by gsprince [/i]
[B]"one instance can have two or more databases opened at the same time"

Are u sure on this jmodic?. I was under the impression its the other way.

BTW, I have non ops databases with different instance name and database names [/B][/QUOTE]

My humble appologies to all for my nonsences in this thread! I don't know what I was thinking... Sure you are right, as was mary in the original question. So, the correct statement is:

In OPS two or more instances can have one (common) database opened at the same time On the other hand, one instance can never open more than one database at the same time.

Again, sorry for the confusion.

What sonaliak's tnsnames files show are not in fact instances, they are "tnsnames alliases" or "service names" as they are now called in 8i (although they sometimes are refered as "instance names" or simmilar, even in Oracle documentation and help files). To avoid further confusion, I'm talking about SUP.WORLD, prod.WORLD etc from his tnsnames.ora. This are only aliases, pointing to actual databases. Sonaliak, you have four different databases with (most probably) four different instances, operating on theree different machines. Only one of them (the one on host Oracle816) is 8i, all other three are pre-8i releases. But your tnsnames alliase definitely are not pointing to the same database.