That part about fast loaders bypassing the serial bus and using the user port is incomplete at best, incorrect in practice. Some early fast loaders did this but most others just used the existing serial bus connection with their own routines, bypassing the buggy kernal drivers on the drive and host side.

There are more errors in the text, e.g "the 1541 used a single-density (narrow) read/write head". No, that describes an 80-track head while the 1541 used a wider 40-track head. I stopped reading here because of these errors.