The longtime, tried-and-true hard drive remains the backbone of a workstation's storage subsystem, but a new breed of solid-state technology is pushing its limits. Although they share the same basic technology as their ancestors, today's drives are much bigger, faster, and cheaper. Traditional workstation hard-disk drives (HDDs) primarily come in a 3.5" form factor, supporting SATA or SA-SCSI standards.
Essentially the same models that ship in corporate and consumer branded PCs, SATA drives are less expensive, sometimes dramatically so. (A terabyte for $50, anyone?) Pricing increases with drive capacity and RPM, an indication of how quickly the mechanical platter can spin within the drive and therefore how fast the drive can read and write data. The least-expensive SATA drives support 7,200-RPM speeds, while the highest-performance options jump to 10,000 RPM.
The second HDD option, the SA-SCSI drive, requires a motherboard interface that is also compatible with SATA drives (whereas a SATA interface will not support an SA-SCSI drive). With SA-SCSI, you'll get the option to move up to 15,000 RPM, but you'll sacrifice capacity and cash.
The Choice Between Speed and Capacity
Whether you choose a SATA or SA-SCSI drive, you will generally face a trade-off between paying for more RPMs or paying for more capacity, because buying both can be costly. Most CAD professionals would opt for capacity and costeffectiveness, because running out of space or money is usually a more glaring roadblock than facing modest shortages of access speed and disk bandwidth. Many of us are paranoid about running out of disk space — and we all should be to some degree, because data piles up faster than we think it will. If this describes you, consider purchasing extra drive bays that bring more room to add drive capacity later — although you can always fall back on external drives to shore up capacity down the road.