Complex sentence: In its favor, the Adam had a large software library from the start--it was derived from, and compatible with, the Colecovision's software and accessories, and, in addition, the popular CP/M operating system was available as an option.
Split into simpler sentences: In its favor, the Adam had a large software library from the start. It was derived from and compatible with the Colecovision's software and accessories, and, in addition, the popular CP/M operating system was available as an option.