The IBM's PC equivalent of the Amiga's RDB is the master boot record (MBR).
Unlike its PC equivalent, the RDB doesn't directly contain metadata for each partition.
The partition data includes the start, length, filesystem, boot priority, buffer memory type and "flavor", though the latter was never used.
The data in the rigid disk block must start with the ASCII bytes "RDSK".
Thus it could safely coexist with a master boot record, which is forced to be found at block 0.