This book is Volume 4 of the series, FYSOS: Operating System Design, and will show the reader how to detect, initialize, and communicate with the Serial and Parallel Ports, the PS2 ports, and the mice and keyboards that may be attached to them, as well as the Sound Blaster Audio device. This book does not, however, discuss input devices attached via a USB port. This type of device is described in Volume 8 of this series, "FYSOS: The Universal Serial Bus". All of this is done without any outside help, such as operating system calls or the help of the BIOS. The reader will learn how to communicate with the hardware directly, reading and writing to the system bus to achieve these tasks. The companion CD-ROM contains complete source code of each example within the book, showing how to accomplish these tasks. This book, and its companion series of books, does not expect you to build the next great wonder of the computer world. It simply will help you with your interest in controlling the computer's hardware, from the point the BIOS releases execution to your boot code to the point of a fully working Graphical User Interface. It is not required that you know much about operating system design, though a good knowledge of C Programming Language and a moderate knowledge of an Intel(R)/AMD(R) x86 computer's hardware is expected to use this book.