The parallel ATA specification has defined the standard storage interface for PCs since the protocol was introduced in the 1980s. Parallel ATA led for three main reasons, low cost, broad operating system support, and steady evolution. Parallel ATA evolved to support higher speed and performance while maintaining backward compatibility with older ATA devices. However, for a variety of reasons, including performance headroom, cabling issues, and voltage tolerance requirements, a new storage interface was required. Therefore, the Serial ATA interface was defined. Officially formed in July 2004 by incorporating the previous Serial ATA Working Group, the Serial ATA International Organization (SATA-IO) provides the industry with guidance and support for 15 year old technology with a high speed serial bus supporting up to 10 years of future expansion.
Advanced Host Controller Interface (AHCI)
Intel has driven standardization of the Serial ATA host controller interface through AHCI for several years. AHCI describes the register-level interface for a host controller for Serial ATA. The specification includes a description of the hardware/software interface between system software and the host controller hardware, and is intended for hardware component designers, system builders and device driver (software) developers.
Intel is helping lead an industry working group that has developed a new interface specification designed as a replacement for the parallel ATA interface. Known as Serial ATA, the new serial interface is designed to overcome the limitations of parallel ATA in addition to providing further enhancements to the storage subsystem in today's platforms.
Because it combines software transparency, low cost, scalability, and design flexibility, Serial ATA has attracted widespread industry support through the Serial ATA-IO and previously in the Serial ATA and Serial ATA II Workgroups. Dell, Hewlett Packard, Hitachi, Intel, Seagate, and Vitesse are jointly leading this initiative, with broad industry support from over 160 companies that make up the working group. Visit the SATA-IO website for the latest Serial ATA specifications, documentation, news and events.
