Serial ATA Is Moving In

"Parallel ATA will go away," predicts Eric Schou, product marketing manager at Maxtor, based in Milpitas, Calif. "That is the reality that is going to happen."

But it's not just the vendors who are evangelizing ATA. For example, Gartner Dataquest predicts that by 2005, ATA RAID will have 52 percent of the market share in low-end servers compared with SCSI.

ATA is the interface that provides a connection between the hard-disk drive and the host system, and often is referred to as Ultra ATA/100. Since the 1980s, parallel ATA has been the standard interface bus for most desktop storage systems. Now serial ATA,a technology that wraps many bits of data into a packet,is expected to offer a higher transfer speed than its brother technology. For instance, parallel has a 133-MBps transfer rate compared with serial ATA's 150-MBps transfer rate.

In fact, one of the main reasons vendors are developing serial ATA is because parallel had reached its speed limit. "The old cable and interface has essentially run out of gas," Schou says.

One of the highlights that some vendors point to is serial ATA's longer and slimmer cable. Serial ATA cable is roughly 3 feet long, while parallel ATA offers an 18-inch long cable. Moreover, serial ATA has a 7-pin conductor cable, as opposed to the 80-pin cable in parallel. "It's much thinner, so it's easier to route," says Craig Lyons, a product marketing manager at Promise Technology, also based in Milpitas. "You won't have this big spaghetti mess to deal with."

Since serial ATA entails a physical design change, it's not going to be backward-compatible to parallel ATA. "This a very different transition because the physical connection is different," Schou says. That means the technology will go through a transitional phase where both interfaces will co-exist on the market for a couple of years, storage experts say. The cost structure right now for the volume market on serial ATA is too high.

Consequently, experts predict that the desktop PC market won't be adopting this new technology very quickly. "That probably will be the painted picture for 2003," Schou says. "You will see the desktop transition to serial ATA in the first to third quarters of next year."

But Promise Technology, a controller manufacturer, has at least one large desktop deal in the works: "In April, a large tier-one OEM will have a high-end desktop that will ship with serial ATA RAID in it," Lyons notes. Thus far, Maxtor is experiencing a high demand for serial ATA drives from manufacturers in the low end of the enterprise space,areas that deal with fixed-content data or low I/O application, such as security, e-mail and archiving.

For now, demand seems to be concentrated on the small-to-midsize business application. High-transaction applications, such as those in the medical or banking industries, are still relying on the tried-and-true standard SCSI interface to do the job.

According to Schou, some of the push for serial ATA seems to be coming from the system-makers. Without going into detail, Schou says Maxtor has been working with 1,000 industrial-type companies to qualify their serial ATA disk drives for new systems. "The hunger is definitely there," he says. "I think, in many cases, they are just waiting for the hardware and waiting for us."

Besides Maxtor and Promise, several notable companies are working on delivering serial ATA products, but most are in the component stages. These include Adaptec, Fujitsu, IBM, Intel, LSI Logic, Seagate Technology and 3ware.

Adaptec, which is primarily a component manufacturer, expects to begin shipping its serial ATA RAID controller early this year. The company's first family of serial ATA products, which include external RAID subsystems for SANs, is the DuraStor Fibre channel-to-serial ATA external RAID solution, which is expected to ship in the first quarter of next year.

Seagate is offering its Barracuda 7200.7 disk drive, with capacities ranging from 70 GB to 160 GB. Maxtor is working on its Maxline II family of drives, with volume shipments scheduled to begin the first quarter of this year. IBM has a prototype of serial ATA Deskstar drives, while LSI Logic has a high-performance MegaRAID adapter, but the product is not shipping in volume yet. Meanwhile, Fujitsu has offered its serial ATA hard disk drives as samples to certain partners; Intel's serial ATA controller 31244 is expected to be available in the first quarter of this year,

but the Intel RAID Controller SRCS14L has been available since the fourth quarter of 2002.

3ware's Escalade 8500 family of serial ATA controllers is currently shipping. And finally, Promise Technology offers its SATA150 TX series of SATA controller cards, as well as its FastTrak S150 ATA/150 drives.

But while many vendors are starting to deliver serial ATA on the components side, the remaining variable is how quickly the overall market will accept this new technology and replace parallel ATA.

Promise Technology's Lyons says his company is familiar with market resistance. About six years ago, Promise was one of the first companies to start delivering ATA RAID controllers.

"At the time, people said, 'You can't do RAID with ATA. You have to use SCSI,'" Lyons recalls. "These people thought the performance was not there. They thought the reliability was not there. With a lot of these perceptions, there probably was a basis for them maybe 10 years ago. But once Ultra ATA drives came out, they were much faster. The quality of the drives these days is much better."

Major companies such as Dell, Hewlett-Packard and Intel are all shipping systems that use ATA RAID, Lyons adds.

More recently, a company called Asaca, based in Golden, Colo., put a disk-based library,which scales up to 48 TB,on the market, based on ATA technology. "It's pretty much a proven technology at this point. Serial ATA is going to push the envelope further. So, now we are going into new markets where we still hear these perceptions," Lyons says.

Take note: Vendors are predicting that serial ATA will have a long and scalable lifeline. Take Seagate Technology, which on its Web site details the technology's performance growth. The first generation of serial ATA has a rate of 150 MBps, a 1.5-GBps bus speed. By the third generation, which is expected to hit the market in 2007, the technology should run at a 600-MBps rate, with a 6-GBps bus speed.

"The need for storage is growing, but budgets are not," Lyons says. "People are looking for lower cost. That's what has been propelling this trend for ATA and serial ATA. For example, video surveillance is one vertical market where you'll find ATA RAID being used quite a bit. When they went from tape to digital, they immediately looked at ATA. It's like they just leap-frogged over SCSI."

Lyons agrees that serial ATA will impact the lower end of the storage and server areas first. Also, expect to see serial ATA used for nearline storage. Asaca recently introduced its disk-based library called FireFly, which uses serial ATA drives.

In fact, Asaca executives say one of the best aspects of serial ATA is that "a point-to-point connection allows multiple drive ports to be aggregated into a single controller, so that capacity-hungry environments can respond quickly to changing storage requirements." That gives IT managers more control over scalability and cost.

Still, ATA has its skeptics. Paul L. Poynter, a product development and support manager at Rorke Data in Eden Prairie, Minn., says his company will have a 16-bay chassis JBOD (which stands for just a bunch of disks) with 16 serial ATA drives that use I/O modules to convert from Fibre Channel. That means the Fibre Channel card within the host will just see a 16-bay Fibre Channel JBOD. The problem is the cost of the chips.

"The cost of the chips they are using to convert from serial to Fibre is very expensive right now," Poynter explains. "And it's going to be several months before the volume comes up to get the cost down. So it's going to be six months before we see decent storage products with decent prices."