RBA,SCN,UBA,DBA,XID

Redo byte address - RBA
size 10 bytes
RBA=LOG Sequence Numer.block number within redo log.byte number within log

System Change/Commit Number
size 6 bytes
SCN=base(2 bytes).Wrap(4 bytes)

Database Block Address - DBA
size 4 bytes
DBA=upper 10 bites(file number) & Lower 22 bits(block Number)

Undo block Address - UBA
size 7 bytes
UBA=dba of undo block.Sequence number.Record number in block

Transaction ID - XID
size 8 bytes
XID=USN(undo segment number) of transaction.undo segment header transaction table slot.Sequence number(wrap)

Redo log
 header
 redo records
   redo record header (contains Thread,RBA,LENgth of record in bytes,SCN,date timestamp)
   change vectors
     header (contains CHANGE number, change TYP, CLSass, Absolute file number, Relative DBA, SCN, Sequence Number, Operation Code)
     array of change record lengths
     array of change records