Editing MESI protocol (section)

=== Read For Ownership ===
A ''Read For Ownership (RFO)'' is an operation in [[cache coherency]] protocols that combines a read and an invalidate broadcast.  The operation is issued by a processor trying to write into a cache line that is in the shared (S) or invalid (I) states of the MESI protocol. The operation causes all other caches to set the state of such a line to I. A read for ownership transaction is a read operation with intent to write to that memory address. Therefore, this operation is exclusive. It brings data to the cache and invalidates all other processor caches that hold this memory line. This is termed "BusRdX" in tables above.