Capacity Versus Performance and Other Economic Realities

Of course, capacity improvements do not provide the full picture of the future of disk drive technology. In addition to capacity improvements, performance improvements must also be considered . The speed with which data can be accessed from disk is increasingly important to end-users and may also be a determinant of the useful life span of magnetic disk drive technology.

Industry observers claim that moving to secondary actuators with high-capacity drives will be required not only to read and write narrower tracks more accurately, but also to facilitate better overall drive performance and throughput. The increasing rotational speed of drives, intended to improve drive access times, also necessitates the implementation of secondary actuators (called fine motor actuators) for every head in order to obtain the same (or improved) rate of performance from faster and more capacious disk drives .

Other enhancements required for improved performance will include smoother disk media with greater head texturization in order to facilitate decreased read-write head fly heights and more accurate reads of smaller bits. New fluid dynamic bearings will also be needed to replace steel or ceramic bearings that both wear out and emit audible noise when platters spin at speeds greater than 10,000 RPM.

According to most industry insiders, we are at the beginning of a true bifurcation of storage technology ”not, as marketeers would have it, between platforms optimized for files and others optimized for blocks ”but between disk drives optimized for speed and disk drives optimized for capacity. Signs of such a split are already here.

According to one industry insider, data transfer rates are increasing at 40 percent per annum, compared to the 130 percent improvement in disk storage capacity. In the past, disk drives were not bought based on performance, but on price.

Traditionally, most consumers preferred a bigger drive at the lowest possible cost, even if it offered lower performance. They didn't want to pay extra dollars in most cases to obtain a performance improvement. The return to the drive manufacturer for a 30 percent performance improvement was only about a 10 percent increase in its list price.

However, new demands are being seen for faster drives: in the business enterprise computing market, where high performance disk arrays are commonly deployed, and also in network-attached storage, where data needs to be shared and accessed by a number of users or servers. Some industry insiders project that at least two types of disk storage platforms are in the offing: one comprised of small form factor, high-performance/low-capacity disk to address the needs of high-speed transaction processing systems, and the other comprising large-capacity/ low-perfomance disk to address the need for data that is less frequently accessed but that requires disk-based storage none the less.

Despite the current debate that is raging over the relative suitability of high-performance SCSI/Fibre Channel-attached arrays versus lower cost ATA and Serial ATA arrays (see below), the bifurcation of disk described above is still in the future. Economics will have a major role to play in the speed at which new, more capacious disk drives will enter the market.