Ask the Slot Expert: Why do RNGs generate such large numbers?

Why does the RNG have to pick a number from 0 to 4 billion and then map it to the virtual reel? Couldn't the RNG easily pick a random number between 1 and the number of virtual stops? Does the fact it picks such a large number affect the volatility of the game?

Thanks,
Jim

Dear Jim,

I can think of three reasons why the output of an RNG falls into such a large range. First, the larger range means that the RNG can have a larger period -- that is, the number of numbers that can be generated before the RNG repeats itself.

Second, the large range means that the output can be used for almost any purpose. For example, an RNG that generates numbers between 1 and 32 is useless for a machine with 256 stops. The output from an RNG that generates numbers between 1 and 4 billion can always be mapped to a maximum of 32, 256 or any number less than or equal to 4 billion.

Finally, the large range and long period make it more difficult to reverse engineer the RNG algorithm -- if an RNG cheat was somehow able to gain access to the raw RNG output.

The RNG has no effect on a machine's volatility or long-term payback. Those statistics are determined solely by the virtual reel layout and pay table. The RNG is just a method to select virtual stops such that each virtual stop is equally likely to be chosen.

Best of luck in and out of the casinos,
John

Send your slot and video poker questions to John Robison, Slot Expert, at slotexpert@comcast.net. Because of the volume of mail I receive, I regret that I can't reply to every question.