Major PC technology companies - including Compaq, Microsoft, and hard drive maker Maxtor - have announced support for a new technology standard that breaks the 137GB barrier for ATA hard drives, at the US-based at PC Expo (part of TechXNY) this week. With capacities that double roughly every 12 months, hard drives have a long history of outgrowing other technologies around them. Many of the roadblocks in capacity have had to do with limitations in the operating system or the PC's low-level basic input/output system (BIOS) software, which prevented the systems from recognizing drives larger than a certain size. But the latest capacity snag results from the ATA standard for locating information on a hard drive. Using a 28-bit addressing system, today's ATA interface can track up to 137.4GB. Drafts for the latest ATA standard, version 6, include a proposal to increase the addressing system from 28 bits to 48 bits. That will increase the maximum possible hard drive capacity more than a millionfold from 137.4GB to 144 petabytes (a petabyte equals 1 million gigabytes). It may be some time before hard drive manufacturers produce a drive with petabytes of space, but Maxtor officials say they expect to offer drives with capacities in excess of 137GB this year. Another interface standard, the small computer system interface (SCSI), uses 32-bit addressing that can handle drives of up to 2.1 terabytes (or 2100 gigabytes) and can transfer data at high speeds. But SCSI has traditionally been limited to high-end, high-cost PC workstations and superfast servers, while ATA is used for internal desktop and notebook PC drives. Big drives already on the way Although a 137GB drive may sound gargantuan, it's well below the maximum capacity already possible. In June, hard drive makers Seagate and Maxtor both announced a new generation of drives that squeeze 40GB onto a single, two-sided hard drive platter. With some desktop drives containing as many as four platters, 160GB capacities are now within reach. Under the current standard, however, a PC can read only the first 137GB on that drive. For the moment, vendors are holding the line on capacity. Seagate's new U Series drive and Maxtor's DiamondMax D540X can contain up to two full platters for capacities of 80GB. Maxtor has also produced a 100GB drive, the DiamondMax 536DX, which contains three platters that average 33.3GB each. Meanwhile rival manufacturer Western Digital is expected to release its own 100GB drive later this summer, and IBM will probably not be far behind. Maxtor is planning even bigger drives for release later this year. "Maxtor is committed to breaking the 137GB barrier in 2001," says Richard Jorgensen, the company's director of strategic and technical marketing. Stretching the standards In its quest for bigger hard drives, Maxtor built a coalition of companies called the Big Drive Initiative to push for adoption of the new ATA standard. Members include Compaq, CMD/Silicon Image, Microsoft, Ontrack Data International, Phoenix Technologies, Promise Technology, StorageSoft, and Via Technologies. They say the most crucial steps are to update the controller chips on hard drives and to write new drivers that allow operating systems to use 48-bit data addressing. Maxtor representatives say new drive chips are on the way, and Microsoft has voiced its support. "We are very pleased to be working with Maxtor to enable increased capacity for our mutual customers," says Rob Short, Microsoft vice president of Windows-based operating system development. It is not yet clear, however, when Microsoft will incorporate the drivers into Windows, and if it will also provide them for earlier versions of the operating system. Maxtor representatives say Linux drivers are already developed, but Apple Computer Inc. has not yet said whether Macintosh will support the standard. Other PC components such as cables and motherboards should not require upgrades, according to Dan Harvey, director of US marketing for chip set maker Via Technologies. However, Harvey speculates that some older BIOS programs may balk at the new addressing scheme, and that some of those BIOSes may not be upgradable. Who needs a monster drive? Now that the path has been cleared for bigger drives, will anyone need them? IDC analyst Dave Reinsel foresees demand for ever-larger drives in the data warehouses that store video and other multimedia content. "There will always be demand for big drives in enterprise storage for serving up rich content," Reinsel says. But he doesn't predict much demand for more storage in desktop PCs, where sales have flattened in part because today's machines have more power and capacity than most buyers can use. Advanced applications that tax the latest processors and hog storage are certainly in use, however, most notably in the digital-video editing realm. With uncompressed video consuming as much as 13GB per hour, even a 100GB drive will quickly fill. Hoping to stoke customer demand for the latest products, both PC vendors and hard drive makers have been promoting video editing as the hot new home pastime, but few people have taken up the hobby, according to IDC's Reinsel. "Until [video editing] becomes much more simple, the average consumer is only going to need 20GB-40GB hard drives," Reinsel adds. While most people aren't interested in making films, plenty of couch potatoes are happy to watch them, and this could represent the greatest market for giant hard drives in the home. Digital video recording devices or "set-top boxes" from companies such as Dish Network, TiVo, and WebTV have been slow to catch on partly because of their limited capacities. The hard drives in set-top boxes currently max out at 60GB - which is not enough, says Reinsel, who confesses he'd like to archive the entire Seinfeld television series at DVD quality. And while he doesn't expect much short-term need for bigger hard drives in PCs, Reinsel foresees nearly limitless demand for set-top boxes. "I think they need to get up to 100GB and beyond if they are going to be worthwhile," Reinsel says. Of course, these capacities will be useful only when a majority of homes have high-speed broadband Internet access, according to Gartner Dataquest's chief hard drive analyst John Monroe. "There is only so much data storage we can meaningfully use, until we have greater bandwidth," Monroe says.