In 2003, 10 terabytes of Xserve RAID storage cost $41,196, and if you had absolutely, positively had to have it overnight, you could tack on $2,320 in shipping charges. That works out to $4.35 per gigabyte. With the announcement of Apple's new 750 GB drives, 10.5 terabytes of Xserve RAID, shipped at Apple's expense (albeit not overnight), costs $13,799, or $1.314 per gigabyte.
The only fudging of those numbers is temporal.
Dollars per gigabyte is a little tough to get one's mind around as a measure of value, especially since there's more to judging an enterprise storage device than capacity. I'll give you some insight into one aspect of Xserve RAID that distinguishes it from other 10+ TB arrays costing less than $15,000. I'll tell you how Apple makes its own enterprise hard drives.
To Apple, the Seagate 7200.10 750 GB ATA drive is a raw mechanism, not a standalone device that's suited to go straight into service. It's a long journey from the Seagate carton to the Apple Drive Module. Apple only accepts 100 percent defect-free drives from Seagate--hard to come by for such a dense device--and those select drives have to pass a rigorous burn-in by Apple without reporting any new sector defects or soft (recoverable on retry) errors. Apple has Seagate burn custom Apple firmware onto every drive, and Apple extends the firmware on Xserve RAID drive controllers to match the specific characteristics of each new drive model. Predicting a skeptical question, the firmware change does not alter the devices' ATA compatibility; it extends the drives' feature set so that they mate more intimately with Xserve RAID's controllers.
Xserve RAID provides full compensation for the differences between desktop and server hard drives in terms of validation for 24/7 usage and high MTBF (mean time between failures), autonomous on-drive logic that monitors drive health and reacts to trouble conditions, the ruggedness of the enclosure and connectors, and the ability to hot swap without data loss or circuit damage. By the end of the process, Apple Drive Modules are rated for continuous server use and covered by AppleCare as such. ADMs take on SCSI-level smarts when they plug into Xserve RAID.
For perspective, Seagate's highest capacity server-validated SCSI drive holds 300 GB and retails for around $700. I'm a SCSI snob from way back, and I'd never use desktop ATA or SATA drives in a server. ADMs in an Xserve RAID become smart and bulletproof devices. That's no Apple brochure talking. That's a lifelong server storage wonk speaking from experience.
So, does $1.31 per gigabyte seem a little more impressive now?