Around about 1990 on, 2 companies tried to expand the basic Midi so as to allow more sounds etc, 1 was Roland with the GS system, (Popular in the US and used on all Windows computers) and 2 was Yamaha with the XG system, (Adopted by pretty much the rest of the world) theoretically both should be able play standard files, but as is usual both manufactures wanted to dominate and so things were changed to try and outdo the other, and this is why mappings between manufactures don’t match.
(One of the downsides of a free market, fortunately the ups outweigh the downs)
Bill
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English Riviera:
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