A content addressable memory (CAM) includes a memory region containing a plurality of word memories, an address storage section for storing address data specifying a partial region of the memory region, and overwriting means for overwriting the contents of word memories in a region in the memory region...http://www.google.com/patents/US6385072?utm_source=gb-gplus-sharePatent US6385072 - Content addressable memory using part of memory region to store data which should not be erased
