The set of AT Attachment standards consists of this standard and the ATA implementation standards described in AT Attachment 8 ATA ATAPI Architecture Model ATA8 AAM The ATA ATAPI Command Set 2 ACS 2 standard specifies the command set host systems use to access storage devices It provides a common command set for systems manufacturers system integrators software suppliers and suppliers of intelligent storage devices Figure 1 shows the relationship of this standard to the other standards and related projects in the ATA and SCSI families of standards and specifications.