In the fall of 1977, Radio Shack started advertising the TSR-80 microcomputer for Christmas. There are two levels of microcomputers being considered by farmers. These are: Level I and Level II. Level I micros are the lowest cost and most popular systems. The three most common Level I micros in agriculture are the Radio Shack, Apple, and Pet Commodore. The more common level II microcomputers that farmers are considering are: Northstar, Vector Graphics, Super-brain, Hewlett Packard, and Cromenco. There are also other brands but they tend to be less popular. One Level II microcomputer that is fairly popular is the Northstar. Country Side Data out of Utah is selling agricultural software for the Northstar computer. There are several differences in the Level II micros as compared to the Level I micros. The key differences are: basic language compilers that are faster than Level I interpreters, and 80 character screens that make VISICALC and communications easier to use.