This book is mainly a reference for the SCSI Interested professional. It will not cover the IDE interface in as much detail as you would like. If you think you will be speaking specifically to a hard drive via code, you will have to memorize interrupt values, AND pay very close attention to the protocol information. This book isn't quite what you think,nor was it what i expected. Although an informative reference for basic SCSI devices, i'm still searching for one that will help me program for hard disks. Hope this was helpful.