Beyond mankind's universal and apparently insatiable desire to have everything right now, is there any reason to spend extra money for an 8X, 10X, or 12X drive, much less their promised 14X and 16X successors? In a word, yes. Whether you find yourself playing back video clips or browsing large databases, you'll appreciate the performance edge offered by a truly fast CD-ROM drive.
While users will more than likely be pleased with the performance edge offered by high-speed drives, some unpleasant aspects of the fast set emerge in routine testing. A few high-speed drives emit a faint but noticeable high-pitched noise that users with sensitive hearing might find annoying. That unpleasant noise has already been cited as one reason that one of the first commercially available 10X drives, Pinnacle's ten-speed 10Xtreme, was pulled from the market shortly after release. Also, internally mounted high-speed drives tend to consume slightly more 5 and 12-volt power from a host PC's power supply than their lower-speed counterparts. Although none of the new drives is likely to inflict an unmanageable overload on its host, users should be aware that adding an extra ampere or two can make quite a difference in an already heavily loaded system. Power-consumption data for drives can usually be gleaned from manufacturers' specifications.
A typical survey turns up 14 models from the growing high-speed scene--seven featuring SCSI connectivity, six using IDE, and one drive that attaches to a PC's parallel printer port. Drive units made available for evaluation include 8X drives from LG/GoldStar, MicroSolutions, Mitsumi, Philips, Plextor, and TEAC; 10X models from Ocean Information Systems, Pioneer, and Wearnes; and 12X drives from Acer, Mitsumi, Plextor, and Toshiba. The numbers continue to soar ever higher for resold editions of 8X, 10X, and 12X drives, and many manufacturers are promising drives reaching speeds of 16X and beyond by second quarter 1997.
Acer's 12X drive features a four-button front panel, in which a pair of pushbuttons smoothly increase or decrease audio when pressed, and the remaining pair handle track-skipping and disc ejection chores. A green LED shows drive activity. A "12X" logo on this caddyless drive's disc-access door comprises the sole styling touch.
Rear-panel connectors include power, IDE data, master/slave jumper field, analog audio, and a pair of pins labeled "digital audio." Audio playback sounded fine on amplified speakers fed via the rear connectors and sound card, but an intermittent front-panel jack on our well-traveled sample drive rendered hearing headphone audio a dicey process.
If production versions perform as well as the engineering sample submitted for review, Acer's drive should provide formidable competition for other IDE 12X drives.
Front-panel styling touches include an "8Xspeed" logo on the drive's door and a molded-in recess that looks like a handle for emergency disc extraction but doesn't offer purchase for a thumbnail. Instead, you poke a straightened paper clip through the now-familiar front-panel hole to eject a stuck disc. On the drive's rear apron, a row of connectors includes IDE, power, analog and digital audio, and master/slave selection pins.
CD Tach chugged through its 8X benchmarks with no surprises, and the drive handled all three VidTach trials without dropping frames or glitching the audio soundtracks. Our text-search benchmark consumed a little over seven seconds--about the same as for the TEAC CD-58E. Under Windows for Workgroups, audio playback sounded fine whether amplified or heard through headphones.
The LG/Goldstar 8X ships with a suggested retail price of $159.
Advertised as an 8X CD-ROM drive, MicroSolutions' Model 166700 provides a comprehensive suite of audio features--FM sound synthesis, audio recording and editing, and OLE compliance under Windows 3.1x. The drive even includes a loudspeaker for playing back sound samples and audio CD tracks when no external loudspeakers are available.
The Backpack drive's relatively featureless front panel includes a headphone jack and volume control, drive-active LED, and eject/load pushbutton for controlling the caddyless disc tray. On the busy rear panel, a quintet of miniature jacks support audio input and output connections, and a second volume control handles amplified audio and the internal loudspeaker.
DB-25 plug and socket connectors and an included three-foot-long extension cable allow you to insert the Backpack in your PC's printer path. An external power supply provides the drive with low-voltage AC that's controlled by a rear panel-mounted toggle switch on the drive. The whole kit--drive, AC adapter, and cable--weighs in at a whisker over 5.5 pounds, a consideration if you regularly find yourself lugging a laptop and other equipment through airports.
Software consists of two disks containing DOS and Windows installation routines for drivers and MicroSolutions' versatile AudioRack software. The DOS version politely asks if it's okay to modify AUTOEXEC and CONFIG, but doesn't automatically make backups of existing files.
While the 32-page drive-hardware manual contains installation instructions for Windows 95, installation of the evaluation unit exhibited only an empty icon and no disc playback capabilities. A visit to MicroSolutions' Internet site yields updated drivers for Windows 95 and Windows NT that, when installed under Windows 95, restore the drive to health.
MicroSolutions labels the Backpack 166700 as an 8X drive, with an average access time of less than 180ms and a maximum transfer rate of 1,200KB/sec, with both manufacturer's specs tagged with an asterisk. Fine print under the asterisk notes that the 1,200KB/sec transfer rate is achieved only "Using an Enhanced Parallel Port. Performance will vary according to port type. Specifications subject to change without notice."
MicroSolutions includes a small utility (CDDRIVES) that tests a PC's parallel port for the presence of a Backpack drive and the type of port to which it connects. The utility confirmed an enhanced (WORD EPP) port on the test PC.
According to results of CD Tach's benchmarks, MicroSolutions' drive falls considerably short of 8X performance--4X would be more like it. Under VidTach video benchmarking, the drive dropped large numbers of frames on the 2X, 4X, and 6X video-clip playbacks. Expanding Windows 95's CD-ROM buffers to their maximum settings didn't improve performance. Audio CD playback sounded fine, both via headphones and an external amplifier and loudspeakers.
It's possible that the Backpack drive can achieve 8X data transfer performance under certain circumstances, such as using a "clean" EPP port and a low-overhead operating system, but benchmarks made in testing couldn't confirm those possibilities. Still, if you need a portable CD-ROM drive for routine data extraction, for a moderately priced $499, look no further.
Both drives present relatively spartan and anonymous front panels graced only by a thumbwheel volume control, a disc-ejection pushbutton, a headphone jack, and an amber drive-active LED. A tiny hole below the slideout caddyless disc tray allows for emergency insertion of a bent paper clip to remove a disc. And without looking hard, you might miss the distinguishing "8X" or "12X" legend stamped in tiny type on the tray's front surface.
Each drive's rear panel includes connectors for power, an IDE interface cable, four-wire analog audio, and pins for slide-on configuration jumpers. Amenities accompanying units submitted for review included discs containing Microsoft's Internet Explorer (version 2.0) and a clutch of game demos.
Mitsumi's drive-support software comes on a single floppy disk and installs itself in relatively civilized fashion, saving copies of modified files with an .MTM extension as it goes. Ondisk setup notes include versions in six languages, an indication that Mitsumi markets these drives worldwide.
The drive kits don't include cables or 2mm metric mounting screws required for installing the drive, but user's notes of above-average detail and clarity accompany both drives. According to the installation notes, you can install this caddyless drive in a vertical position--flanges on the drive tray keep a disc from tipping outward.
In operation, both the 8X and 12X drives handled all video benchmarks without a hitch. Under CD Tach, the 12-speed drive read 16KB blocks at a true 12-speed rate but fell below CD Tach's 12X CPU-usage mark due to relatively long seek times. Both played audio discs flawlessly through headphones and via an external amplifier and loudspeakers.
One oddity noted in testing was that in the text-search benchmark, the 8X drive took three times as long as its 12X counterpart to locate the test string, even though both drives read the same disc using the same software drivers, DOS settings, and IDE port and cables.
The Mitsumi 8X model carries a manufacturer's suggested retail price of $199; its 12X counterpart lists for $249.
Octek's 38-page instruction manual reflects the drive's international market, offering brief setup instructions in seven languages. Postage-stamp size illustrations offer a general idea of where to make data, power, and audio connections, but a PC beginner would do well to consult the manual for the PC's sound card as well.
Controls include a green drive-active LED, a front-panel disc eject/load pushbutton, and a button that initiates audio-disc play and track selection. When you press the drive's ejection button, a four-second delay elapses before the disc drawer opens. Users can play an audio disc directly without having to run CD-Audio software, but Octek's README file cautions against using the front-panel controls during software playback. Front-panel markings consist of slightly raised and barely legible identifying symbols and a bold "10X" logo on the drive door.
Rear-panel connectors include IDE data, four-pin power and audio connectors, and a master/slave selection-jumper block. The Octek CDR810 sports an easily legible rear-panel label that identifies connector functions--a welcome detail. This caddy-free drive accepts full-size and mini discs. Windows 95 Device Manager identifies the drive as an Oak (OTI) Scylla F011 with V200 firmware.
According to CD Tach, Octek's 10X drive performs flawlessly at 8X but doesn't quite make the 10X cut. Under the Vidtach benchmark regime, our review drive encountered a few erratic playback problems during the fastest video clip, dropping a fraction of a percent of the video frames and introducing an occasional audio break. The drive handled the medium and low-speed clips and CD-Audio discs without glitches or complaints.
The Octek 10X carries a list price of $169.
Emblazoned with a silver-dollar size Philips medallion, this 8.5-inch wide, 10-inch deep, 2.5-inch high package features boldly raised lettering and a gray stacking bar that runs the length of the top of the case and matches a recessed indentation in the bottom of a second drive.
The stacking bar and rounded edge make this drive a precarious perch for coffee cups and other beverage containers--a bad idea with conventional drives but an especially high-risk proposition with the Philips enclosure. Front-panel controls include play/pause, open/close, and forward and reverse buttons, and a thumbwheel volume control for the mini-stereo headphone jack.
Philips wins the award for best light-show among high-speed drives with three indicators--yellow drive-active and green power-on LEDs on the front panel, and a green-illuminated AC power switch on the rear panel. The PCA80SC's rear panel includes full-size SCSI connectors, RCA phono jacks, an AC power connector, and a flush-pushbutton SCSI ID selection switch--the latter effectively prevents accidental address changes.
There's also an exhaust port for the drive's internal cooling fan, which contributes little noise to an audible whine produced by the drive's spin motor. The motorized caddyless loading tray includes recesses for full-size and miniature discs. During testing, the submitted engineering-sample drive appeared to encounter intermittent difficulty in centering and mounting inserted discs.
Loading glitches aside, the PCA80SC performed at 8X transfer rate standards and proved generally competent and speedy in handling data and A/V files but skipped many frames during playback of the highest-performance video clip in the benchmark suite. Also, our review sample's front-panel audio control showed scratchiness when adjusted, and headphone audio distorted badly at a full-volume setting.
The internal Windows version of the Philips 8X model carries a list price of $199.95; the 8X external unit for Macintosh sells for $249.95.
The engineering-sample drive submitted for review arrived accompanied by four pages of notes, in English and French, that briefly describe this drive's most unusual feature. Pioneer's dual-mode motor drive spins a disc in either constant angular velocity (CAV) or a combination CAV and constant linear velocity (CLV) mode.
In CAV mode, the disc spins at a constant 2160RPM, which is equivalent to 4.3X at the track extremity closest to the disc's hub, and 10X at the disc's outer edge. In combination mode, the disc spins up in CAV mode to an 8X rate at the hub. As the optical pickup moves outward, it reaches a 10X rate and the disc motor switches to CLV mode, maintaining the 10X rate all the way to the disc's outer edge.
Both combination and CAV modes performed acceptably during video benchmarking and didn't drop frames or introduce audio breaks. In straight CAV mode, the drive didn't quite achieve 10X performance, due most likely to a decrease in 16KB block readback rates from 1,540KB/sec to 1,431KB/sec. Audio playback sounded fine, both on headphones and via an amplifier and loudspeakers. Probably as a consequence of its dual-mode platter motor, the DR-433 draws a little more DC power from its host PC's 5-volt supply--1.3 amperes (1.8 amperes peak)--and a relatively modest 0.3 amperes (1.0 amperes peak) from the 12-volt supply.
While most existing CD-ROMs are not mastered to take advantage of the strengths of a CAV-capable reader like the Pioneer 10X, the reading mode represents a potentially useful mode that may yet gain popularity. If it does take hold, Pioneer's DR-433 will put its users ahead of the pack.
Pioneer's 12-speed DR-444 extends the CAV/CLV concept to IDE/ATAPI drives, offering respectable but not stellar performance. According to CD Tach benchmark results, the engineering sample of the drive submitted for review misses its advertised 12X (1,800KB/sec) specifications by running at a 16KB block transfer rate of 1,681KB/sec. Up front, the DR-444 presents a spartan control panel consisting of a headphone jack and volume control, a drive-active LED, and a disc-ejection pushbutton. The rear panel presents no surprises, either, by carrying the usual IDE-drive connectors and configuration jumpers.
Under the remainder of our benchmarks, the DR-444 showed glitch-free video and played back audio CDs equally well. With a little tuning of its performance, the production version of the DR-444 should provide a solid CLV/CAV alternative to straight CLV drives.
Weighing in at just under six pounds and occupying a 12 by 7-inch desktop footprint, the PX-85CS harmonizes nicely with other beige PC peripherals. A pair of LEDs--green to show the presence of a disc and amber for power on/busy status display--and Plextor's corporate logo and "8PLEX" legend silkscreened in blue add welcome tinges of color to an otherwise bland expanse of plastic.
Labels for controls consist of hard-to-read raised legends and symbols that protrude slightly from the drive's front panel. Pushbuttons for disc ejection and track selection include molded-in symbols. The disc-access door hinges downward, exposing a drive cavity that accepts standard disc caddies. You can insert a caddy with one hand, but catching the drive door's lip with the caddy's edge takes a little practice.
A tiny hole that allows insertion of a straightened paper clip to eject a disc in power-off emergencies offers a touch of comfort familiar to Macintosh users. A front-panel volume control and miniature stereo jack for headphones round out the front panel's controls. Out back, the PX-85CS sports a rear-panel AC power rocker switch and a DIP switch for selecting bus termination, parity checking, block-mode operation, factory-test mode, and front-panel disc ejection lockout. Users set the drive's SCSI bus address via a tiny rotary switch that should resist misaddressing caused by rear-panel fumbling.
Connectors include RCA-style phono jacks for audio, a three-wire AC power jack, and a pair of miniature, high-density SCSI-2 jacks. A generous number of ventilation openings in the drive case's sides allow for convection cooling.
Plextor's utilities installed relatively smoothly under DOS, with only one minor glitch. The installation routine states that it saves existing versions of CONFIG.SYS and AUTOEXEC.BAT under ".OLD" extensions, but doesn't actually do so if those files already exist. For DOS users who find themselves running out of lower memory, it's worth noting that Plextor offers a SCSI driver that supports only CD-ROM drives and can install in upper memory. In contrast, third-party SCSI drivers that support scanners, tape drives, and other peripherals generally consume much more lower memory and leave less for DOS.
In use, the Plextor PX-85CS passed the 8X road test and handled all benchmarks competently and without calling attention to itself, including in tests for video and audio playback. Plextor Manager, a Windows utility, manages drive setup and allows you to slow drive speed to as low as 1X, which is a bonus if you use older CD-ROMs or CD-Rs that won't load or play back error-free at faster speeds. Other features include a CD audio player and a nifty channel-selection routine that lets you swap audio output channels, and more. The PX-85CS carries a suggested retail price of $355.
Like its 8X and 12X SCSI stablemates, Plextor's internally mounted PX-12CSi offers no-compromise performance at its rated speed. On its front panel, the PX-12CSi shares styling details with the 8X PX-85CS, but necessarily parts company in rear-panel controls. Users select drive address, SCSI-bus termination, and parity via two-pin jumper blocks as described in Plextor's richly detailed 68-page operations manual.
The drive ships with a cable kit that includes a pair of audio cables--one for patching audio to a Sound Blaster or compatible card, and a second with identical four-pin connectors on each end. An included SCSI cable features dual connectors--ideal for adding the PX-12CSi to an already existing SCSI hard drive--but its 18-inch span to the first connector may run a little too short for installation in full-height PC tower cabinets. A pair of slide-in side rails with mounting hardware, a CD caddy, and Plextor's Manager software round out the accessory complement.
Under CD Tach benchmarks, the PX-12CSi racked up full 12X performance and outperformed every other drive in the CD Tach Multimedia Ratings. Video performance likewise ran smoothly, with no audio glitches or dropped frames. Music CD playback worked fine under Windows for Workgroups 3.11 and Windows 95. In summary, Plextor's PX-12CSi offers first-class performance at a you-get-what-you-pay-for price. The Plextor 12X model retails for $349 (internal), and $399 (external).
A pair of floppy disks contains installation software, including 8x Navigator (a system diagnostic that checks for existing drives) and 8x Installer. The latter considerately makes backups of AUTOEXEC.BAT and CONFIG.SYS but doesn't let users choose a destination directory for its drivers. While 8x Navigator makes a long stride toward easing setup woes, its error messages may leave users wanting more information (e.g., a definition of IRQ interrupts and addresses).
Hardware provided in the CSD-880E kit includes mounting screws, a 16-bit ISA IDE controller board, an 18-inch, dual-connector IDE cable, and an 18-inch audio cable terminated in two styles of sound-card connectors. A well-presented 34-page user's manual recaps installation instructions and provides troubleshooting tips.
Up front, the drive's minimal controls--a headphone jack and volume control, an amber drive-active LED, and a single disc-ejection pushbutton--are enlivened by a fingernail-sized blue "8X Speed" label that appears stuck on as an afterthought. On its rear panel, the drive sports the usual power, IDE, and audio connectors, plus an IDE master/slave selection jumper and a mysterious two-pin connector labeled "reserved."
Sony's CDU311 breezed through CD Tach, providing solid 8X performance and respectable multimedia and application ratings for a drive of its class. Video and audio benchmarks passed without glitches or hiccups, and audio CDs sounded fine both amplified and via headphones under DOS and Windows. Selling at a manufacturer's suggested retail price of $139, Sony's CSD-880E drive kit offers respectable 8X performance and--thanks to simple and well-documented set-up--a high "comfort factor" for new users.
TEAC's bare-drive review kit includes 18-inch IDE and 25-inch internal audio cables and 12-page hardware and 16-page software installation guides. A single floppy contains installation routines for both DOS and Windows 3.1x. The DOS routine doesn't automatically create AUTOEXEC and CONFIG backups but does allow you to either reboot your PC or exit to DOS upon completion. A single front-panel disc-eject pushbutton and the usual audio fittings comprise this drive's control "suite." Press the button and the disc tray snaps out smartly, and faster than most other drives reviewed. According to the user's manual, drive power consumption runs at a thrifty 5 volts and 0.3 amperes, and 12 volts and 0.6 amperes--lower than for other drives reviewed.
Under the CD Tach benchmark regime, the CD-58E returned respectable results and true 8X performance. In VidTach benchmarking, the drive handled all three tracks flawlessly, and audio playback sounded fine. The TEAC CD-58E retails for $149.
Up front, the drive presents an anonymous front panel graced by the usual suspects--headphone jack, volume-control thumbwheel, LED indicator, ejection button, and an emergency-ejection hole. A bottom-side label identifies the rear-panel connectors--plus power, IDE data, analog audio, and master/slave jumpers. The connector suite also includes a two-pin plug for digital audio and a field of jumpers labeled "mode select 2" that's not further explained.
According to CD Tach benchmark software, the Toshiba XM-5702B logged respectable 10X performance and performance indexes but fell short of 12X capability. Under VidTach, the drive replayed all three video clips without dropping a frame, and our DOS text search averaged just over three seconds, which measured up to standards set by its 10X-level competition.
Playback of audio CDs didn't go as smoothly. With the included DOS driver, the unit had working audio under Windows for Workgroups 3.11 but would not play an audio CD under Windows 95.
While playing audio under Windows for Workgroups, the drive also showed low left-channel audio relative to its right channel, and its headphone jack made inconsistent contact.
The Internal ATAPI 12X that Toshiba submitted for review retails for $165; its external SCSI counterpart sells for $195.
| Although none of the new drives is likely to inflict an unmanageable overload on its host, users should be aware that adding an extra empere or two can make quite a difference in an already heavily loaded system. Power-consumption data for drives can usually be gleaned from manufacturers' specifications. |
The Multitaskin' CDD-1020's front panel sports a volume control, headphone jack, drive-active LED, and a pair of buttons for audio-play track selection and disc ejection. On the rear panel, the connector lineup includes the usual suspects: power, IDE data, master/slave jumper, four-wire audio, and an unlabeled two-pin connector. The driver setup routine modifies AUTOEXEC and CONFIG without creating backup copies. When you exit, the setup routine posts a "you must reboot" message and begins emitting shrill beeps from the PC's internal speaker. A normal CTRL-ALT-DEL three-finger keyboard salute won't restart your PC--reach for the reset switch instead. One hopes that a more intelligent, more user-friendly setup package accompanies the production release.
When benchmarked, the CDD-1020 barely made it over the 10X drive hurdle, utilizing 69 percent of the CPU's resources at a 1,500KB/sec transfer rate. The drive stumbled its way through the fast VidTach benchmark, dropping over 50 percent of its frames and causing nine audio breaks. Performance on low and medium-performance video benchmarks and audio discs was flawless.
The Wearnes Multitaskin' 10X retails for $188.
Of the drives reviewed, three models supplied by Wearnes, Philips, and Pioneer arrived as engineering samples and are worth a look in their production versions, as wrinkles encountered in testing may have been ironed out by the products' shipping dates. Of the three, the Pioneer drive proved competent at handling video playback and offered solid benchmark performance. Also, the Pioneer DR-433 uniquely provides dual-mode CAV/CLV operation.
Plextor's PX-85CS and 12Plex present outstanding multimedia performance and emerge as our first choice among SCSI drives for high-performance applications. Mitsumi's FX-12T and FX810T respectively offer reasonable 12X and 8X performance in an IDE package and will meet the needs of less demanding users, as will TEAC's CD-58E, a good choice for an 8X IDE drive if your PC's power supply is running near its capacity. Octek's CDR 810 didn't quite qualify as a 10X drive under CD Tach benchmarking, and its performance at the fastest video benchmark fell a little short of perfection. And if you need a portable 8X CD-ROM drive that operates from a parallel port, MicroSolutions provides the only game in town--but the game is not a particularly fast one, especially compared to the pace set by the rest of CD-ROM's fast-emerging jet set.
The PC's operating systems consisted of MSDOS 6.22 (used for the text search benchmark) and Windows 95 (used for CD Tach performance and VidTach video-playback benchmarking). As a reference point, results were also included for the test PC's native internal quad-speed SCSI CD-ROM drive, a Sony CDU-76S.
Written by Greg Smith of TestaCD Labs of San Jose, California, CD Tach performs a variety of tests, including 16KB and 2KB block reads, full-disc and random seeks, and percentage of CPU usage. [See Brad Thompson, The Driving Range," CD Benchmarking: Taking a New Tach," EMedia Professional, January 1997 --Ed.] In general, lower CPU usage frees CPU resources for processing and decompressing video, resulting in higher Multimedia ratings. Faster seek/read access times raise a drive's Application rating.
To run the benchmarks from as level a playing field as possible, Windows 95's CD-ROM caching was adjusted to the minimum allowable values--a 4KB read-ahead cache, and a 60KB overall cache. Each benchmark run consisted of five passes, whose averaged results form the data shown in the chart.
One drive--MicroSolutions' Backpack 8X--exhibited performance below its manufacturer's specifications, and retesting the drive with Windows 95's caches maximized yielded no significant improvement in performance. CD Tach produces two ratings--one for multimedia playback and a second for general applications--in which larger numbers indicate better performance. Differences of only a few points in drive performance are insignificant.
As an additional benchmark, XTree Gold for DOS' fileviewing capabilities were used to open and search a 3MB text file containing Canadian amateur-radio operators' callsigns for VY2ZZ, the last record in the file. Testing consisted of timing a minimum of three runs via stopwatch and averaging the results to produce the "DOS Text Search" data shown in the chart. While IDE drives produced a wide spread in retrieval times, it's interesting to note that as one might expect, the Sony CDU76S 4X SCSI drive benchmarked (but not reviewed) took twice as long to complete the search as did the 8X SCSI drives reviewed.
Greg Smith's VidTach benchmark counts the number of frames in an AVI video clip and computes an average frame rate in kilobytes per second. During playback of the video clip, VidTach counts the number of frames skipped by the drive and also notes any breaks in the audio playback. Testing was done using three video clips, including WEEZER.AVI, a 243KB/sec track from the Windows 95 upgrade CD's high-performance directory, and two tracks supplied by Plextor on version 3.6 of their demonstration disc. One track--MONTE6.AVI--delivers video at 673KB/sec, and the other--B12HI1.AVI--delivers its video at 1,154KB/sec. --Brad Thompson
The carousel's operator also offers you the kind of ride that a disc experiences in a conventional CD-ROM drive. No matter whether you sit on an inside, middle, or outside horse, the operator guarantees that the breeze in your face will always blow at the same speed. Here's how: the operator slows the carousel's motor if you choose a horse in the middle, and slows it even more if you choose an outside horse. You travel at a fixed number of feet per minute--a constant linear velocity (CLV).
A CD-ROM's data consists of pits and lands stamped in a reflective coating and uniformly spaced along a single spiral "track." In CD-ROM's original design concept, a drive reads a disc's data at a constant rate. Pits and lands flow beneath the drive's optical pickup at a constant linear velocity (CLV). To accomplish this, a disc's rotational speed decreases as a drive's optical pickup moves outward from the disc's hub.
In CD-ROM's early days, CLV worked fine because in a single-speed drive, a disc at its fastest spins at a pokey 500RPM. However, CD-ROM's designers never envisioned a 12X drive, in which a disc spins at over 6,000RPM (maximum). Manufacturing defects--an off-center hub hole or an imbalance--cause vibration-induced data-retrieval errors. In addition, during random seeks accelerating and slowing a fast-spinning disc can impose severe performance demands on a CLV platter motor and its electronics.
As market forces spur the development of 8X and faster drives, some designers have introduced the dual-mode CAV/CLV drive to extract as much performance as possible from non-uniformly made discs while minimizing hardware costs. In one design approach, at startup the drive's platter-motor controller attempts to spin the disc at a full 12X rate, but any excessive disc vibration triggers a fallback to a lower speed.
From there, the drive operates in CAV mode, reading data at a variable rate over the inner third of the disc or until the data stream reaches a 12X rate. The motor then switches into CLV mode to retrieve the remainder of the disc's contents at a 12X rate, eventually slowing to 2,400RPM as the pickup approaches the disc's outer edge.
Potential pitfalls of mixed-mode operation include variable-speed data extraction during CAV operation--a source of glitches when reading and decoding high-performance video clips. Also, partially full CD-ROMs may contain only 100 to 200MB of data, and thus a dual-mode drive may never reach its higher-performance CLV mode before running out of data to read.
Of more concern to the industry, unsophisticated users may purchase a mixed-mode drive that advertises 16X performance without understanding that true 16X data retrieval may occur only near the disc's outer edge. Over the remainder of the disc, data rates may vary from 8X upward--a respectable value but not the across-the-disc 16X performance for which the customer paid.
Dual-mode drives offer one main attraction: at an affordable price, they extract the maximum performance from CD-ROM media forced to operate far beyond original specifications. While next-generation benchmarks will show how CLV/CAV data-retrieval rates vary over a disc, will manufacturers openly share this data with customers?
If not, dual-mode drives will become just another short-lived sideshow in the CD-ROM circus, an act the industry can ill afford with DVD hardware sliding into a roller-coaster market. --Brad Thompson
Today, however, even as 4X CD-ROM-equipped desktop systems remain the norm in some quarters, shipping models boasting 8X, 10X, and 12X capabilities--based on promised data transfer rates of 1,200, 1,500, and 1,800KB/sec, and seek times as low as 130ms--come in more than a dozen varieties, and that doesn't even count resold and rebranded configurations of original manufacturers' drives. And just over the high-speed horizon--and closer than that, in the cases of some just-released models--are drives claiming performance ratings 14 and 16 times as high as CD-ROM's single-speed Generation No-X.
Like some 10X and 12X drives, these new faster models accomplish these performance peaks in three ways: spinning at a constant linear velocity (CLV), a constant angular velocity (CAV), or in a combination of the two [see Brad Thompson's sidebar, "Dual-Mode CAV/CLV Drives: Sideshow or Main Attraction?" --Ed.]. Along with basic performance specs, most 14X and 16X manufacturers have released spinning-mode data with the announcements of their latest models.
LG Electronics has introduced two new drive models, the GoldStar CDR-8160B and the GoldStar CRD-8161B, that use CAV/CLV rotation technology to deliver, according to the company, 16X drive performance. LG's published specs list the drives as having a 2.4MB/sec data transfer rate, a 100ms access time, and an 128KB buffer. The CRD-8160B, a tray-based model, and the CRD-8161B, a slot-loading drive, are internal ATAPI drives that can be mounted horizontally or vertically, with list prices not determined at press time.
Mitsumi Electronics Corporation has debuted an internal, half-height ATAPI CLV/CAV drive model, the Mitsumi 16X CD-ROM drive, which features a 2.4MB/sec data transfer rate and a 120ms access time. Designed to be plug-and-play compatible with Windows 95 and OS/2 Warp systems, the half-height drive boasts a 256KB buffer and lists for $249.
NEC has also announced a new 16X drive model, a no-brand, OEM-only internal CAV/CLV unit which will be available in early 1997 for bundling by PC manufacturers.
First quarter 1997 finds Sony Electronics announcing three new drive models for OEM-only availability. The Sony CDU415 is a 12X internal or external SCSI drive that promises a 100ms access time and became available for OEM licensing in January. Following in February will be the CDU511 16X Max, an internal ATAPI model with a Sony-spec'd 95ms access time. And March will mark the introduction of Sony's CDU571 16X Max Slot, a slot-loading 16X counterpart to the CDU511.
Toshiba America Information Systems, Inc. has announced the XM-3801B, a new internal CLV/CAV SCSI-2 unit that delivers data, according to Toshiba, at an average 14X speed over the course of an entire disc and a 15X performance peak. Promising a 90ms average random seek time and 2,100KB/sec average data transfer rate, Toshiba says the tray-loading XM-3801B has a 256KB buffer and carries a suggested list price of $290. --Stephen Nathans
![[LiveLink]](/file/36067/SIGCAT 97 - Conference on Convergence.ISO/Docs/webcd.gif "[LiveLink]"){kind=small}
LG Electronics
1000 Sylvan Avenue, Englewood Cliffs, NJ 07632;
201/816-2000;
Fax 201/816-2188;
http://www.goldstar.co.kr;
cdrom@lge.goldstar.co.kr
MicroSolutions, Inc.
132 West Lincoln Highway, DeKalb, IL 60115;
800/890-7227;
Fax 815/756-2928;
http://www.micro-solutions.com
Mitsumi Electronics Corporation
6210 North Beltline Road, Suite 170, Irving, TX 75063;
214/550-7300;
Fax 214/550-7424
Ocean Information Systems, Inc.
688 Arrow Grand Circle, Covina, CA 91722;
818/339-8888;
Fax 818/859-7668;
http://www.ocean-usa.com/ocean/
Philips Media Systems
2121 Wisconsin Avenue NW, Suite 400, Washington, DC 20007;
202/965-5931;
Fax 202/ 337-2514;
http://www.philipsmedia.com/systems
Pinnacle Micro
19 Technology, Irvine, CA 92718,
714/789-3000;
Fax 714/789-3150;
http://www.pinnaclemicro.com
Pioneer New Media Technologies, Inc.
Multimedia and Mass Storage Division, 2265 E. 220th Street, Long Beach, CA 90810;
800/444-6784, 310/952-2111;
Fax 310/952-2990;
http://www.pioneerusa.com
Plextor Corporation
4255 Burton Drive, Santa Clara, CA 95054,
408/980-1838;
Fax 408/986-1010;
http://www.plextor.com
Sony Electronics Corporation of America
Computer Peripheral Products Co., 655 River Oaks Parkway, San Jose CA 95134;
408/432-0190;
Fax 408/943-0740;
http://www.sel.sony.com
TEAC America, Inc.
7733 Telegraph Road, Montebello, CA 90640;
213/726-0303;
Fax 213/727-7672
TestaCD Labs
402 Galleria Drive, Suite 11, San Jose 95134;
408/435-8773
Toshiba America Information Systems, Inc.
Disk Products Division, 9740 Irvine Boulevard, Irvine, CA 92718;
714/457-0777;
Fax 714/583-3131;
http://www.toshiba.com
Wearnes Peripherals International (Pte) Ltd.
801 Lorong 7 Toa Payoh,
#04-00 Wearnes Technology Building, Singapore 3219319;
+65-259-8933;
Fax +65-354-0242
Brad Thompson, EMedia Professional's The Driving Range columnist, is a freelance writer and electronics design engineer based in Meriden, New Hampshire.
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