I'm looking for one of the following: - ATA-4 Specification - A wrapper for the ATA-4 specification written in Real Mode Assembly (MASM/TURBO ASM)
http://www.ata-atapi.com/hist.html#T18
ATA/ATAPI-4 is ANSI document number INCITS 317-1998.
(see also http://t13.incits.org/t13sd4.htm)
If you want to read the actual ANSI standard you have to purchase it. Not sure who is the best source but I did find one source online.
as far as assembly libraries go... that sounds like a tough call, I found something but no idea as to its viability/correctness/licensing.