One of the most popular of the "Special Cartridges" the Extended Basic cartridge was a vast improvement over the BASIC which came loaded on the console. It pretty much became a standard, and many commercial software products required extended basic. With extended basic you can load many TI basic programs that will then run faster than they did in TI basic. There are some limitations though so not all programs will work in Extended basic. There are also loaders for Extended Basic that allow you to load assembly language programs.