server use, though applicable to higher-end workstations as well; and third, SCSI drives holding more than 11 GB, for servers and audiovisual applications.
We asked each of the major disk vendors to submit up to two drives in each of our three categories. We received test units from Fujitsu, IBM, Maxtor, Quantum, Seagate, and Western Digital. At test time, Hitachi and Samsung said they had no appropriate models available. And Micropolis, which had shown some interesting new disk drives, was abruptly and inconveniently put out of business by its Singapore parent company.
This last event brings up an interesting point:
the shrinking community of disk drive producers. According to data from Western Digital, in 1985 there were nearly 60 disk drive manufacturers in the market. Today, only about a dozen makers account for virtually all the drives sold. Ironically, even though the number of hard disk vendors has decreased, hard disk storage continues to be a thriving business. The American Stock Exchange announced last fall the addition of a new equity index (DDX) composed of companies that manufacture computer disk drives of all form factors and capacities, as well as related components.
The unrestrained growth in disk storage should raise a warning flag when it comes to backup. With disks so large, your backup system has to be equally capacious. In "The Changing Face of Backup", we take a look at the growing array of backup options: removable media, tape and disk, magnetic and optical. Solid-state's much too expensive for backup.
For our tests, vendors submitted the highest number of drives in the middle-size,
server-class
category, where 9 GB is the apparent sweet spot, the size that most network administrators will be most interested in. Large capacity plus a small form factor (the standard is now 3-1/2-inch drives just 1 inch high) combine for cost-efficient RAID arrays. Also, this amount of storage seems to represent the threshold at which a service technician can manually replace a drive and restore or reinstall its applications in a single day. Plus, you can plug in these models as direct replacements for your currently installed 4.5-GB drives.
In comparing disk drives as disparate as this current group, we considered that drive capacity would, to some extent, be an indicator of typical use. The smaller drives are more likely to be used in workstations and desktop applications, while bigger, faster drives, especially those with a SCSI connection, are prime candidates for use in servers. And then there are the two biggest drives -- IBM's 18-GB Ultrastar and Seagate's 23-GB Elite -- whi
ch are likely to find use in large server installations and in video production.
When it comes to disk drives, BYTE considers three factors: performance, reliability, and price. To evaluate this new crop of drives, we tested performance by measuring data throughput. Some vendors have made a lot of noise about designs with faster access times, higher rotation speeds, improved resistance to vibration and shock, and bigger on-disk caches. But, for practical purposes, all those parameters can be subsumed in one test by measuring throughput.
To test throughput, we installed each drive in a Dell Optiplex GXpro 200 with 64 MB of RAM. The IDE and ATA drives were connected to the on-board Enhanced IDE (EIDE) controller, and the SCSI drives were connected to an Adaptec AHA 2940W/2940UW SCSI controller.
We feel that many specific design choices really don't matter in the end to most users, provided the drive delivers data as quickly as it's called for. Similarly, problems associated with vibration (as
might be encountered in a server's large array of drives, for example) show up mainly as thermal asperities and, ultimately, in reduced throughput. The features table (see print edition for full table; partial table can be found as the last article in the Hardware Lab Report section) details the specs for each drive.
Ultimately, we recognize that the drives we tested -- big as they are now -- will be considered midgets in a few years as newer and nonmagnetic technologies enter the market. Even with magnetic disk drives, as Ed DeJesus explains in "Infinite Space", manufacturers are achieving ever-greater storage densities by using magnetoresistive (MR) and MR-extended (MR-X) heads in place of the older, thin-film technology. Western Digital was the last major disk drive manufacturer to adopt the newer head design. Now IBM, which invented MR and MR-X technology, has announced a giant MR (GMR) head that permits record/playback densities of 10 times what we're seeing in early 1998. The company has already
announced the first GMR drive, one that packs more than 16 GB into a 1-inch-high form (and one we plan to review in an upcoming issue).
So look over our test results and product specs, then buy whatever disk drives you need right now. But you should realize that the picture is likely to be radically different in another year.
Contributors
Steve Platt, Managing Editor/NSTL
Dorothy Hudson, Project Manager/NSTL
Maryanne Eves, Acquisitions Editor/NSTL
Russell Kay, Technical Editor/BYTE
Michelle Campanale, Technical Editor/BYTE
Linda Higgins, Editorial Associate/BYTE
illustration_link (58 Kbytes)
Illustration based on the IBM Ultrastar 18XP.
Storage Part 1: 15 Disks Cover More Data Than Ever
