hi German,
You can find all ATA/ATAPI standars drafts(in pdf format) in:
http://www.t13.org/#Project
drafts
Best Regards,
Sera
Well i have the project to make a parallel port to EIDE interface, but it is not ease to find the basics on standar commands of EIDE devices such Hard Drives or CD-ROM, if you know about any resources or info about this, please mail me. Thanks for your atention German