SATA: Evolutionary or Revolutionary Disk Technology?
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Serial ATA (SATA) is a glossy new storage technology designed with the intent to eventually supplant parallel ATA (PATA). According to some industry experts, SATA storage solutions could cut the price of high capacity, server-attached storage by as much as 60 percent. But, if that's really the case, what's keeping SATA from taking the storage market by storm?
The Adoption of a New Technology Takes Time
According to Knut Grimsrud, Intel's technology initiative manager, as with any technology, it not only takes time to move from first products in the market to broad market availability, it also takes time to educate mainstream consumers about the benefits, and it takes time to get IT managers to qualify the new products.
Joni Clark, Seagate's Serial ATA project manager, says SATA has been embraced by the entire industry like no new industry standard before it. "The adoption rate for SATA is expected to reflect the usual requirements of the market, because as chip makers, controller and motherboard vendors, and hard drive manufacturers release various products, those markets that can best take advantage of SATA's new features first will most likely be the early adopters." In addition, Clark believes that as higher volumes enable cost parity with parallel PATA products, adoption will ramp up more quickly and SATA will ultimately replace PATA in all areas where PATA now plays a leading role.
SATA: Improving Integration Efficiency
A primary motivation behind developing SATA was to improve integration efficiency. This is accomplished, according to Grimsrud, by reducing the pincount necessary to support the interface as well as by reducing the signaling voltages to better accommodate the latest manufacturing processes. "These characteristics make SATA inherently more efficient to integrate than PATA, and it is expected to translate into a long-term cost advantage over PATA," claims Grimsrud.
Tracy Yang, LSI Logic's manager of its RAID Storage Adapter, says the SATA standard is aimed at resolving the key shortcomings of the PATA interface while retaining a cost advantage due to the following characteristics:
- Point-to-point connection for higher performance -- 150MB/sec per drive
- Thinner and longer (1m vs. 18 inches) for easy routing
- Hot-swap capability, first party DMA, and enhanced reliability with the addition of 32-bit CRC error correction
- Better connection design for easy installation and better device reliability
- Connector size that allows 2.5" FF drives
- No 5 volts legacy, allowing for the deployment of new silicon technologies
SATA II and Cost Reductions
Hardware based on the Serial ATA II specification is expected to appear by 2004. SATA II will be compatible with SATA 1.0, but it will feature some SCSI-like qualities that SATA presently lacks. If hard drive manufacturers match SATA II with some server-rated devices, inexpensive drive technology could possibly drive down the acquisition cost of low to mid-range servers, which will definitely have an effect on the storage industry as a whole. "The present day economic situation will challenge vendors to respond in a variety of ways; however, the SATA Working Group will continue to define technology that meets customer's demands," Grimsrud says.
Yang says that even though PATA rules the majority of the low-end servers and workstations market and SCSI has the majority of the enterprise server market, the future generation of SATA II products will create a market share shift from SCSI to SATA. "With improvement of reliability and availability, the SATA II product is poised to penetrate into some enterprise storage systems, but it will be a task for hard drive manufacturers to match enterprise-level features (speed, reliability, mechanicals) with the low price that has typically been identified with the IDE/SATA market."