Following is an interesting discussion about Keno RNG from the Yahoo Keno Forum:
Ive been spending a lot of time researching these video keno
machines and the supposed RNG's they have in them and here's a few
things iv'e discovered about how an RNG really works (and its not
the way were led to believe)
Conventional electronic gaming machines work in the following
manner. Each game has a set of rules, known as a combination, and a
set of winning and non-winning outcomes. A player makes a wager and
starts the game and the machine determines the result of the bet.
This determination involves a random number generator (RNG) being
used to select one of the winning or non-winning outcomes, of which
there could be millions of possibilities, and the game then
displaying this outcome in some fashion.
An example of the above would be a video spinning reel game. Once
the player presses a "Bet" button, the RNG is used to select
a "stopping position" for each of the reels. These are the final
positions of the spinning reels, to be displayed at the end of the
game. The game software does not immediately display these stopping
positions. Rather, it first starts the reels spinning from the
previous stopping positions and continues to spin the reels until
each of the RNG derived stopping positions comes into view on
screen. As each stopping position reaches the correct point on
screen, the reels are stopped. Thus, the player gets the impression
that the derivation of the final position of each reel was done at
the end of the reel spin rather than at the beginning.
The reason why game outcomes should be known before the game cycle
finishes is that, in the event of a failure of a machine during the
game cycle, it is important that the machine does not alter its
behaviour. By predetermining and storing the outcome in non-volatile
memory, the machine can ensure that if power is lost during a game
cycle then, upon resumption of power, the game can continue to the
same conclusion.
Another approach to a predetermined outcome would be to model a
physical system using software within the gaming machine. In the
example of a keno or bingo game, the previous predetermined method
would be for the software to select a ball which is going to be
produced from the on-screen cage, and then display an animation of
this outcome occurring. The problem with this method is that, unless
a large number of animations are stored, it quickly becomes apparent
that this is not an accurate simulation of a keno game. Modelling
the physical system using software would mean, in the case of keno,
starting all of the 40 or so virtual "balls" at random positions
within a virtual "cage". The simulation software would then simulate
the effects of gravity, collisions and all the other forces which
would cause the balls to move around randomly within the cage. As
the simulation progressed, it would be represented on the gaming
machine's screen. At the end of the simulation one of the balls
would be "picked" by the simulation which displays a graphical
representation of a mechanical arm picking the ball in an analogous
way to the way conventional physical lottery machines work.
This approach has some advantages. It would produce a much more
realistic looking display of a keno game and would appear to the
player to be far more random. Unfortunately, this very randomness
would also make it far more difficult for the game software to
accurately know which ball is going to be selected, since selection
takes place at the end, not the beginning, of the simulation. It
would therefore be up to the gaming machine manufacturer to try and
prove that the physical system being modelled was sufficiently
random in its outcome and, more importantly, free of bias.
Modelling physical processes is relatively straightforward, but the
interactions are such that, although it is easy to model from a
starting position to derive an ending position--so it is easy to
model a ball being dropped on a roulette wheel and then run the
simulation through till the ball stops and see where it stops, it is
much more difficult to start with an end position and try to derive
the starting position that lead to the end position. In the case of
roulette this would be akin to trying to derive a starting position,
velocity and acceleration for a roulette ball in the croupier's hand
from an end position that was at rest and in one of the numbered
slots on the roulette wheel. Clearly, this would be an exceptionally
difficult task.
So as you can see from part 1 of this post these RNG's arent
generating random numbers on your screen theyre generating random
numbers to figure the outcome of your game and how much theyre gonna
pay.Heres some more info i came across also.
So if i bursted anyones bubbles i apologize but i just thought
everyone would find it interesting that you can play any numbers you
like and it wouldnt matter its up to the machine wether or not your
gonna hit. And also thought it would help to describe why when your
watching these so called random numbers pop up on your screen that it
keeps paying only a limited amount by hitting the same amount of
numbers everytime and how its possible to hit so many numbers out of
your wheels without ever paying off the big hit .