I have a linear tracking turntable that used to belong to my father. He had 4 of them and this is the last one I have to sell. This particular turntable was marked with a note that said it needed the belt replaced. The parts are still available for these turntables. The linear tracking seems to work well.
These turntables move the stylus arm parallel with the grooves in the record for better sound and less wear on the record. Many records masters are cut with a linear tracking method and therefore playing a record with the same angle of tracking is better on the record copies that are pressed of the master mold that was produced using the linear process. Thats the long/short explanation.
A laser scans the record, and you can jump between tracks like a CD because the turntable remembers where each track it.