Before 20th century, the word "Slot Machine" was used for gambling machines as well as for automatic vending machines. After that, the term "Slot machine" was started using only for gambling machines". In Britain, it is also called "Fruit machine" and "one arm bandit". The first slot machine was invented by "Charles Fay" in 1895, who was a car mechanic in San Francisco. That slot machine was called "Liberty Bell". It had three spinning reels.
Today's slot machines are based on computers. Playing slots do not require any gambling knowledge unlike other games like blackjack and poker etc. Every slot machine contains a central processing unit for the processing. A "Random Number Generator (RNG)" is used to generate a random number in these machines.
A slot machine may contain a lever or a push button. A random number is generated when the lever is pulled or the push button is pressed. In traditional traditional slot machines, the player pulls a handle to rotate a series of reels which may be three or more. On the reels, there are pictures printed on them. The reels stops where the computer chip tells it to stop. The pictures combination stays with the pay line, a line in the middle of a viewing window, determines winning or losing.
The processor of the machine continuously generates random numbers even if the machine is not in use. When the button is pressed or the lever is pulled, a random number is generated. After that, the generated number is converted into a small number for displaying on the machine on a particular reel position. After generating random numbers, it is computer's work to roll each reel on a particular position so that the result is displayed. A reel has 22 possible stop positions. The stops which are more important are assigned less numbers so that the chances of getting them again are less.
Every player gets equal amount of money at the start of the game. Once the player handed the money he starts playing. There is a time limit for the slot game, if the time limit is over than the person with the maximum money is declared as the winner otherwise the game continues until all the people but one are out, the left one player is declared as the winner. The slot game winners are usually awarded with the cash prizes which are collected through the casinos entry fees.