As the cookbook, the BIOS provides the "recipes" or instructions to the CPU so it can talk with all peripheral devices attached to your PC. However, the BIOS does not know everything. Occasionally it needs additional information to get its job done.

The BIOS gets this information through device drivers. These small programs supplement its "communication recipes" and allow it to provide "new" recipes to the CPU for newer peripheral devices.

Why does your PC have a BIOS chip filled with instructions that contain all the low-level communications tasks that the CPU can use? It's simple. If you let someone else remember all the little details, it frees you up to get the more important work done. And so it is with the CPU.