Oracle RBA

Redo Byte Address (RBA) 

An RBA points to a specific location in a particular redo thread. It is ten bytes long and has three components: 

Redo log file sequence number (4 bytes)

Block number within log (4 bytes) 

the byte offset into the block at which the redo record starts (2 bytes) 

RBAs are not necessarily unique within their thread, because the log file sequence number may be reset to 1 in all threads if a database is opened with the RESETLOGS option.