The future of hard drives: diversification

Computer Technology Review, Oct, 2004 by John Paulsen

The recent explosion of widely varying applications that rely on hard disk drives has led to the greatest diversification in hard drive design in the history of the industry. Initially, the primary challenge was to scale the technology. More recently, as new consumer applications found value in hard-drive storage, the challenge was in leveraging existing technology. Moving forward, the primary challenge is to customize the technology to fit more and more specific and divergent application needs.

What has developed is a new way of thinking about storage and a new way of designing hard drives. Design begins with how the customer will use the storage. Which factors are most important--capacity and price? What about form factor, reliability, scalability, workload and performance? Or data integrity, power consumption, system architecture and interface? And while the emergence of specialized design is relatively recent in the hard-drive industry, it does not appear to be a temporary phenomenon--it's likely to continue as more new markets discover ways to take advantage of the unique capabilities and value of hard drives.

Today, an incredible variety of hard drives range in capacity from 1GB to 500GB and in physical size from 1 inch up to 3.5 inches. They

can serve applications ranging from handheld music players to digital video recorders, game consoles and home servers, printers and copiers, PCs, notebook computers, near-line servers, networked corporate data centers and more. Drives may feature SATA, SAS, or Fibre Channel interfaces or external USB or FireWire connections, and they offer a dizzying variety of spindle speeds: 3,600-rpm, 4,200-rpm, 5,400-rpm, 7,200-rpm, 10,000-rpm and 15,000-rpm.

From a broad list of key technologies that impel the design of a hard drive, the capabilities that one application demands can differ greatly with the requirements of another application. While certain enterprise server applications require very high input-output-per-second (IOPS) within a scalable rack infrastructure, others may need very high capacities or lower up-front costs. Where a handheld music device must be very light, very rugged and consume little power, an audio/video server farm may require massive streaming throughput and data availability above all. Thus, as the hard-drive industry serves more and more divergent application needs, it must design a more divergent set of products--each product designed to closely meet the needs of its target application.

The market today is rife with examples of new hard-drive designs impelled by new applications requirements.

Notebook PC Storage

New applications for notebook computers, both at the office and home, are driving industry-wide adoption of these portable systems as a replacement to desktop computers. With the performance and capacity gap between notebook and desktop drives diminishing, PC users are transitioning to notebook computers and technology is evolving to accommodate their needs.

In notebook PC storage, the diversification of hard-drive technology is clear. As users demand new, more robust applications, designers and manufacturers must revamp their existing products, focusing on performance, power management, capacity, acoustics and smaller form-factor. Hard-drive designers have responded with a move in recent years from one to three available spindle speeds, from one to two available form factors, and with an increased focus on higher available notebook hard-drive capacities and additional onboard cache, further diversifying the hard drives now available for the notebook market.

Notebook computers endure an entirely different type of lifecycle: they get bumped, nudged, opened, closed and powered-on multiple times each day. So disk drive designers have focused on increasing resistance to shock and developing specialized systems to reduce the incidence of head slap.

Enterprise Storage

Meanwhile, driven by a trend in the enterprise to consolidate storage arrays, rack servers and blade servers, we now have the first 2.5-inch hard drives for enterprise applications. The combination of 10,000-rpm performance, small footprint and support of current and future data transfer standards generates multiple benefits, including higher IOPS performance and support for consolidation and scalability. The 2.5-inch size permits three or four more drives in a 1U rack compared with traditional 3.5-inch drives. The drives also produce faster seek times, which is especially beneficial when applications must read and write a myriad of small files. A 2U-rack with these new drives will outperform today's common 3U rack storage array by 150% on an IOPS-per-U basis, while providing equal or greater storage capacity.

In addition to boosting performance, the 2.5-inch enterprise drives increase ROI by facilitating consolidation and management. Performance and capacity can be enhanced without adding more racks or using more data-center floor space. Manageability is easier, since there are fewer servers or arrays in potentially fewer locations. With less cabling and fewer fabric switches, UPSs and rack cabinets, problems are easier to diagnose. Mirroring is simpler, and redundancy is more affordable.