1999 was a year of both evolution and consolidation for SCSI hard disks. The high platter-count of SCSI drives combined with improved areal densities have yielded drives 36 gigabytes in size from major manufacturers. One manufacturer, Seagate, has pulled ahead of the pack with a 50 gig unit.

The most significant of 1999's developments was the entry of Quantum and Western Digital in the 10,000 rpm drive stakes. The two newcomers joined Seagate, IBM, and Fujitsu, creating a situation where all five major SCSI drive manufacturers offer units with blazing spindle speeds. The veterans didn't stay put either: the increase of areal densities by at least 67% over previous-generation models have yielded transfer rates approaching or even exceeding 30 megs a second.

Consolidation in the SCSI market provides an interesting contrast to the segmentation occurring with ATA drives. Increasing pressure to compete for the purchasing power of systems manufacturers pushing out sub-$700 machines have fragmented the 5400rpm drive market. Some manufacturers have introduced "value" lines distinct and separate from their regular 5400rpm offerings. A year ago, the 7200rpm SCSI drive market was the same way. Most major manufacturers offered both an "entry-level" 7200rpm unit (an example being the IBM Ultrastar 9ES) and an "enterprise-class" drive (Ultrastar 9LP) that provided an incremental increase in speed. This year, however, all players combined their 7200rpm families into a single line, thus clearing up the waters considerably.

Things may not remain so tight and simple in the SCSI world for long, however. There are rumblings here and there that at least one drive manufacturer is preparing for a jump to a new spindle speed- 14,400rpm. Such a beast would shave rotational latency down to about 2 milliseconds, a 33% reduction from 10k's 3ms figure. This reduction is significant considering that today's top-of-the-line actuators average an amazing 5ms when seeking.

Ultra160/m SCSI has arrived, raising LVD SCSI's transfer ceiling to 160 MB/sec. Unlike ATA-66, Ultra160/m is a bit more significant: Mature, robust disconnect/reconnect features found in today's drives, controllers, and drivers allow SCSI peripherals to effectively share the bus, transferring data simultaneously. Ultra160/m gives even transfer-rate-heavy usage patterns such as video editing with striped drives headroom to spare.

Some readers may be wondering why StorageReview.com has concentrated only on 18 GB, 1" profile drives. There's a reason why we've standardized on the largest 1" unit in each family. Performance differences between varying-size drives within the same family are insignificant. An exception may rise from the slightly slower seek times that 36 GB, 1.6" drives sport. The differences are relatively minor, however, and something that we assume to be proportional between drive families. In contrast, we've found that increased cylinder depth allows larger drives within the same family to edge out smaller units. More platters mean that more data can be kept on tracks towards the outside, allowing for optimum transfer rates. Taking all this into account, the drives presented here cover just about all drives released so far in 1999. Decide which drive family is appropriate for you based on the performance and comments presented here, then choose the capacity that suits you accordingly.

With the breakneck pace that 7200rpm ATA drives are evolving, some users question SCSI's performance advantages over ATA units. It's in the arena of 10k operation, though, that SCSI exerts its undeniable supremacy. Quite simply, there are no 10k rpm ATA drives yet. Even with the impending shipment of WD's 4.6 gig/platter Enterprise 18310, the Quantum Atlas 10k clearly shines as today's pre-eminent SCSI screamer. It's the downright fastest drive in four out of six categories, where it bests all competitors by significant margins. In the remaining two categories, WD's Enterprise manages to match, but not significantly exceed Quantum's offering. Unlike last year's Editor's Choice (the Cheetah 9LP), the Atlas 10k also sports decent heat and noise levels. Taken all together, the Atlas 10k is simply a darn attractive package.

If you can't put up with the Atlas 10k's heat, noise, or price premiums yet still need to stay SCSI, 7200rpm drives are the only option. Whatever Quantum did to make the Atlas 10k such a screamer must have also been done to the Atlas IV-- it manages to top the competition in much the same way that its big brother does. The Atlas IV is top dog in five of six measures, slipping to Western Digital's Enterprise 18300 only in the Business Disk WinMark run under Windows NT. This is a stunning improvement over its predecessor, the Atlas III, which we found to be the slowest SCSI unit in our 1998 roundup.

In contrast to our recent ATA Drive Roundup there's little ambiguity when it comes to general recommendations. As the results clearly show, Quantum Corp. is today's undisputed leader in SCSI drive performance. Whether you're looking for a 10k or 7200rpm unit, offerings from Quantum simply make the most sense. They're the fastest, fairly quiet, relatively cool, and attractively priced. It's also interesting to note that in both categories, Western Digital merits an honorable mention, offering drives second only to Quantum's in performance. Both Quantum and WD are new players in the 10k drive arena and weren't exactly standouts with their previous 7200rpm lines. Today, however, they've surpassed veterans Seagate and IBM to claim the top perches in today's SCSI hierarchy.