Who Write Undo Information From The DbCache To The Physically UndoDatafile.

Hi,
I Got An Question , Been Searching The Documentation .. Not Getting An Hang Of It.  

I Would Like To Know , If Undo Block Is Brought In The Buffer Cache, During An Update.. SO What Process Write The Undo Block [Old Image] To The Physically Undo Datafile.  

And The Storage Way To Save Information On The Undo Datafile Is Diffrent From Normal Datafile..  

I Would Like Some One To Help Me Explain .. Who Writes The Undo Image And How Is The Flow Work On From Buffer Cache To Undo Datafile.  

Can U Give Me Autentication Of This In The Oracle 9i Documentation.  

My Basic Logic Say So , DBWR Does The Writting Of The Data From The Cache To The Datafile. And UnDo Is Also An Datafile...But A Senior Dba Says Its The Server Process That Does The Writes In The Undo Datafile.  

Its An Senior Dba Word..So I Am Wondering. How Can I Give An Explanation Of Dbwr Doing Writing ..And Not Server Process.  

<http://groups-beta.google.com/group/comp.databases.oracle.server/browse_thread/thread/b086f1f5cb8848a4/d0ead446037ee5a8?hl=en#>

 Thank You ,
 Sheldon Quinny

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