Comment by h0l0cube

This was definitely a thing in the optical disc era of games where seek times were horrendous. In record mode, this is done by just overloading the file read functions, recording a list of file, seek position, and read size instructions, and then using that to build a .dat file. In play mode, the function is overloaded to ignore file opens and seeks, and to just read from the contiguous file. This requires the load to be perfectly deterministic, and preferably without redundancy.