Modern gaming machines use computer technology to operate their functions. Slot machine outcomes are determined unsing a Random Number Generator (RNG) which is a mathematically-based program that selects groups of numbers to determine which symbols are selected to produce a winning or losing outcome.
Overall, there is no strategy that will accurately predict when a slot machine will pay out. That is the whole point of slot machines. They were created to be random, and to not allow people to know when they will hit.
A slot is a connection dedicated to one user on a server. For example, a 4 slots server will be able to welcome up to 4 users at the same time. Do I loose my server data when I renew my server ?