RickB

So - you hit the nail on the head. My day job involves stuff like DSP compiler development, algorithm optimisation and so on. Understanding processor and instruction set architecture is one thing, but it's a different ball game to poking bare metal. I don't suppose you have conveniently documented processor models and hardware specs to work with either!

MAME is even more hardcore! I have no idea how folks managed to reverse engineer ROMS to get them working - they could be entirely custom hardware throughout. I recall that in the late 80s some of the ATARI arcade machines like APB and RoadBlasters were based on the same hardware system, but I don't know how much they really had in common.

For the moment this is just curiousity about how some of these machines were programmed. Maybe when I retire I'd have the time to go deeper down the rabbit hole. Following on from what Mort said, I fired up Albert Square and started to look seriously at the contents of RAM, just as a game to see if I could figure out where the counters were and how they related to the compensators (since both EastEnders and Albert Square have reasonably easy to spot "happy times"). And yeah, it's tough. I think I found three separate counters related to spending credits, always incrementing, not always by 1, with some counters being 8-bit and others 16-bit. No rhyme or reason I could figure out at all. My main achievement was finding where the ASCII display memory was mapped into RAM - whoopie doo

I never got so involved in playing fruit machines that I really considered it a problem. As a student I sometimes spent more money than I should. When I started working it was a few quid here and there - amounts I figured I could afford to lose. I suppose it was still a waste as I never really "won" overall. I still like to bung £20 in the machines when I go to the seaside just for nostalgia's sake, but it's getting harder and harder to find any machines I have fond memories of. Just from the point of view of being able to play those games again, MFME is fantastic. It is probably true to say that MFME is now the only way to play quite a few of the older games - pubs never seem to have old-style fruit machines any more, and even the seaside amusements are changing. MFME also makes it also possible to play these games exhaustively - perhaps trying features that never seemed worthwhile, or exploring how the machine behaves onces it's stuffed full of (virtual) cash.

So I had the original C64 version of Knightmare. It wasn't great, nowhere near as good as the TV show. It *did* feature Granitarse though The video goes on to mention an Amiga version of Knightmare. It looks totally different, with a similar engine to Eye of the Beholder and similar games.

Anybody remember Vegas Jackpot on C64? I played this one too, but it was very limited.

I remember playing Advanced Fruit Machine Simulator on the C64. Codemasters games were great. Never played Fruit Bank, though.

Aha. Thanks Mort, I suspected it wouldn't be so simple as adjusting a simple counter. Maybe one day an ex-employee from Maygay will publish some of this stuff on github or something. If not then it seems the code may have disappeared along with the companies, which would be very sad indeed. It just makes all the work that went into MFME all the more impressive. I know that the MAME project reverse engineered various arcade systems the hard way, and MFME must be no different in that respect.

I'm very new to MFME but I'm already very curious about the payout algorithms used by various machines. They vary wildly in how they behave in situations where you'd think the machine would be very keen to pay out. The old Maygay EastEnders machine was very easy to "read", but some others - such as X Marks the Spot or Crazy Fruits were nigh on impossible to suss out. Since we have no access to the original source code, including the system libraries, it's not really feasible to work these things out by looking at the disassembly (while I am totally fine with C and C++, even if I knew the mnemonics for 6502 or 68000 assembly language, you'd also need an intimate understanding of the hardware and memory maps to really get anywhere). And even though tools exist for converting assembly language back into a higher level language, it would still be very hard to understand without hints from variable and function names, code comments, and detailed knowledge of the hardware. So, it looks like trial and error might be the only way. In MFME, I've played around with using the "C" button to put the machine into configuration mode, then set up the "In" value to try and manipulate the machine's own idea of its current payout status (adjusting it to something like 10%). Am I on the right track? This doesn't seem to have worked so far. Not sure if I'm fiddling with the wrong value, or accidentally overflowing an internal counter, or similar. Thanks for any insight you can give me

This is one of the first computer games I ever played. I would have been about 6 years old! This was a super frustrating but addictive game. I think my mum actually managed to complete the starship - I never had the patience.