> > M.A.C.H. 3 and Us. Vs. Them also do this, although in their cases it's for in-game > > target data and not executable code (IIRC). > > Correct me if I'm wrong but wasn't M.A.C.H. 3 practically the reason MAME realized > capturing output frames from a Laserdisc player and then store them lossless into a > CHD was not an optimal idea to keep preserving data this way?
I really don't know anything about that decision; someone else would have to answer the question.
That said, from having read through the MAMEtesters bug that you linked to, I'm not sure what that would have to do with lossless storage in a CHD. The bug makes it sound as though the real issue was that the video and audio were captured from a damaged disc, and that damage would render the game unplayable past a certain point.