pulleys

Ran into these expressions in the Atlas MOLO table of belt positions & speeds. Could someone explain these "like I'm five"? I thought I knew what the backgears were, but I definitely don't know what "direct cone drive" would be. I just bought a Craftsman 101.07402, my first lathe, and I'm in...

After reading post about vibration I noticed mine had a slight amount of vibration at times so I took a look at the belts while it was running and noticed how much they bounced around and I also noticed the large pulley was not running true as I could see wobble while it was turning and figured...