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Comment by dghughes | Hacker News Reader

My former job of a slot machine tech would often involve setting up a slot machine. The PAR (paytable and reel) sheet had set groupings you could pick. Integrity and Compliance, local government regulators, security, management, superiors, surveillance all watching me like a hawk while I enabled it then seal the chips.

edit: just a note that for years I wasn't even allowed to see or touch a PAR sheet. Literally, not even see or touch the things. They were securely locked up.

Much of a slot machine is "random" but to a point where the house never lost. If it were truly random not pseudo random there would be no way to control what was won or maybe nobody would win at all. Organized chaos really. And most of the time the slot is a 10 or even 20 year old barely functioning piece of junk. The machine has been paid off (so to speak) so any money it makes is pure profit.

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> If it were truly random not pseudo random there would be no way to control what was won or maybe nobody would win at all.

This doesn’t make much sense. You don’t need to manipulate an RNG to ensure the house has an edge - and to my understanding this is generally not done in the big casino venues because it’s not even necessary. Because what you’re essentially suggesting is that machines purposely use poor quality PRNGs - which is absolutely not true. They have in the past unintentionally and have only been burned by it. Utilizing a PRNG does make auditing easier though. And it’s much easier to produce a reliable PRNG than find a reliable source of randomness that is not vulnerable to manipulation. (Having said that, mechanical real machines got by for years without any algorithmic RNG)

Games of chance that utilize effectively true randomness (since the behavior is unpredictable even to the house) have been around for millennia.

Roulette is perhaps an easier example. A typical American wheel has 38 positions: 1-36, 0 and 00. If you bet on a single number and hit, a 1/38 chance, you don't win 37x your bet, you only win 35x. If you bet on Red, or Odd, those pay 1-1 but the odds of winning are less than 50%, there are 18 winning results and 20 losing results. The payouts are always lower than the true probability of that specific outcome. If two people play opposite colors, one Red and one Black, the casino will break even on numbers but collect both wagers when 0 or 00 wins.

Another example is sports betting with a point spread. You bet $11 to win $10, on supposedly an 50-50 wager (the purpose of the point spread).

Slot machines work off the same principles. It's ok for the outcomes to be random, because the payouts are always less than the true probabilities.

The outcome of each individual spin is random. The reason a slot machine is always profitable is due to the payouts. To put it simply, a result that will occur once every 100 spins only pays out 90 credits. The various PAR sheets allow casinos to adjust how much to tilt the odds in their favor. For the 1 in 100 example, the various pay tables might have that particular outcome pay 87, 89, 91 or 94 credits, allowing a casino to decide between 6% all the way up to 13% hold. But that particular combination of reels will still occur only 1 in 100 spins (theoretically, because it is in fact random, not cycling through a script).

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