I am old and getting older but may want to take a step into the tech world. I would like to know the names of all the devices that are on the market that have screens and what they can do, today such as Ipads, notebooks, lap tops and such. What makes them different. I know about Iphones and do not want one of them. Too big for my pocket. Like my flip phone to clip on my belt. But I may want to start using Square readers to take credit cards at shows. Do not need something too large or elaborate but confused with all the gadgets because they all look the same except for sizes. Not to be used often but often enough. Want to have some knowledge when going to talk to the Geeks in the stores. Thanks.