The slot in a library table indicates the slot that is scanned by an optical library during initialization. This is useful when you want to ensure that a particular row in the table is read only.
The original mechanical slot machines worked on a simple principle: the player pulls a handle to spin a series of reels, each with pictures printed on it. If all the reels show winning pictures along a pay line (or certain single pictures) the machine pays out the prize or jackpot. But the technology of these machines has changed dramatically over time.
Now, most modern slots have microprocessors that control the outcome of each spin. They still look like the old mechanical machines, with spinning reels and flashing lights, but they operate on a different principle. Microprocessors allow manufacturers to assign a different probability to each symbol on the reels. So, a losing symbol may seem to appear on the reels much more often than it actually does.
Moreover, the slot has evolved into a more diverse game. You can find slot variations based on TV shows, poker, horse racing and even Vikings. And many of them have bonus features that require some skill to trigger. While this might make slot games less suited to casual players, it also gives manufacturers more creative leeway with themes and storylines. This is why there are so many frankly absurd titles out there – like Vikings Go to Hell, for example.