I'm really not sure, and I'd rather not speculate blindly. I've read about the basics of Mercury Line Memory in the past, and have some books that describe it,

I'm really not sure, and I'd rather not speculate blindly. I've read about the basics of Mercury Line Memory in the past, and have some books that describe it, but I don't know the hard details. BTW, Mercury Line Memory was not the first form of memory used in programmable computers. The "oldest" or "first" is debatable, but the earliest were switches/relays and vacuum tubes (AFAIK). I'd bet jgrahamc would know...