But 20GB drives using today's technology have just one platter and a single pair of heads. Some industry analysts expect areal density to reach 40GB per platter toward the end of this summer. If that happens, we could see drives with capacities of 200GB by the end of the year. Those same pundits expect areal density to double again, to 80GB per platter, sometime in 2002. But hard drive makers say that 80GB per platter is close to the current limit, and that squeezing any more data onto one disk will require the integration of new and more-expensive technologies.
Several factors determine how quickly a drive can read or write data.
In all cases, drives with a 2048KB cache outperformed those with only a 512KB cache. Then there is the matter of how quickly a drive communicates with the rest of the system. That's not surprising. For years, the capacity of the Ultra DMA interface has outpaced the sustained transfer rate of a single hard drive. But the excess capacity present in the interface will be available to accommodate faster drives later on.