Optical drives: A clearer future

Departments and agencies looking for faster, more accessible storage for

backing up data on servers or even critical workstations should take a look

at the latest generation of CD and DVD drives.

These optical technologies have been around for several years, but they

have always been hindered by technical pitfalls. Rewritable CD drives should

have been a no-brainer because of the economically attractive possibility

of reusing CDs rather than throwing them out after one use. But the sluggish

speed of the early drives steered many users away. And DVD-RAM offered

even greater capacity than the CD format but suffered from the same slow

speeds.

But vendors are beginning to correct that situation. The latest rewritable

CD (CD-RW) drives can read and write CDs almost as fast as standard recordable

CD (CD-R) drives. Meanwhile, at the high end, DVD-RAM (rewritable DVD) is

making a reappearance, with second-generation drives besting their forebears

in capacity, cost and performance.

In this review, I tested a pair of devices that illustrate the advance

of mainstream optical media: the Plextor Corp. Plex-Writer W1210TA CD-RW

drive and the Panasonic LF-D211U DVD-RAM drive.

Speed to Burn

Plextor, long recognized for building the fastest and most expensive

CD-ROM drives, has given rewritable CD drives a much-needed boost. By transferring

data at about 1.5 megabytes/sec, or 10X speed, Plextor's PlexWriter W1210TA

makes using CD-Rs seem ecologically irresponsible. The W1210TA burns CD-R

media at a faster rate (12X speed or 1.8 megabytes/ sec) than it does CD-RWs,

but is the difference in speed enough to justify creating a disc that's

destined for the landfill after one use, when a rewritable CD can be erased

and rewritten 1,000 times?

After burning a few dozen discs with the PlexWriter, I am delighted

with this drive despite a few shortcomings.

Using industry nomenclature, this is a 12/10/32 drive, meaning it burns

CD-Rs at 12X speed, writes CD-RWs at 10X speed and reads at a maximum of

32X speed. The read performance is misleading — most CDs are read at the

lower limit of 14X speed to 15X speed — but Plextor is in step with its

competitors in this regard (except for Kenwood Corp., purveyor of TrueX

high-speed CD-ROM readers, which can read at up to 72X speed).

My tests show that the PlexWriter's write performance is within fair

reach of its promise. Averaging a number of best-case tests (writing one

large file to a freshly formatted CD-RW disc), I clocked the PlexWriter

at 1.141 megabytes/sec. A full-capacity CD-RW burn of 650M takes less than

10 minutes — a vast improvement over the typical 20-minute wait imposed

by a 4X drive. A full CD-R burn completes in just less than eight minutes,

faster than CD-RW but not so speedy that you'll forsake the advantages of

rewritable media.

The breadth of Plextor's software bundle is a pleasant surprise. The

latest release of Adaptec Inc.'s Easy CD Creator manages the creation of

music and data CDs. Adaptec's software automatically matches its maximum

write speed to the quality of your media. If you buy cheap CD-Rs or CD-RWs,

Easy CD Creator may knock your write performance down to as little as 2X.

If you want to do high-speed recording, you will need to buy media that's

rated for the PlexWriter's maximum speed. Note that only special high- performance

CD-RW media can handle 10X writes. At around $5 each, the premium rewritable

discs are still an excellent value. The 10X CD-RWs will work in any CD-ROM

or DVD-ROM drive that reads CD-RW media.

For this drive, Plextor wisely licensed a new technology called Burn

Proof. When your computer can't pump out data fast enough to keep up with

a CD burner's write speed, a condition called buffer underrun occurs. In

a drive without Burn Proof, this interruption of the data stream ruins a

disc; you have to junk the CD-R and insert a fresh one. Plextor's drive

is able to resume an interrupted CD-R burn after a buffer underrun, saving

the disc. Burn Proof reclaims the time wasted by aborted CD-R recording

sessions.

My one complaint with the PlexWriter is Plextor's use of an outdated

direct memory access data transfer standard. Instead of conforming to the

popular Ultra DMA specification, the PlexWriter uses a DMA mode I haven't

seen in years.

One of my lab's systems refused to work with the Plextor drive. In another

machine, the PlexWriter had trouble sharing a cable with another CD-ROM

drive or hard drive. I finally got the drive running by letting it have

its own cable. I have no trouble recommending the PlexWriter, but I advise

testing the drive with your specific PC configuration before committing

to a volume purchase.

DVD-RAM Rides Again

The first round of DVD-RAM, like rewritable CDs, left users wanting,

with first-generation products providing about 1.5 megabytes/sec data transfers

and 2.6G per side storage density.

In its second incarnation, DVD-RAM aims to double its appeal. Storage

density and data transfer rates have doubled, and the cost of drives has

fallen dramatically. At about $500, Panasonic's speedy LF-D211U may be the

first DVD-RAM drive that budget-conscious purchasing managers can love.

Other DVD-RAM drive manufacturers include Toshiba America Information Systems

Inc. and Hitachi Ltd., both of which plan to follow Panasonic's lead with

new drives.

As a reader, the Panasonic drive is compatible with a broad range of

media. It will read first-generation (2.6G per side) DVD-RAM, second-generation

(4.7G per side) DVD-RAM, commercial DVD, DVD-R, CD-ROM, CD-R and CD-RW

media. Its read performance places the drive on par with a 6X DVD-ROM drive

or a 24X CD-ROM drive. At those speeds, it is reasonable to employ the Panasonic

drive as the sole optical media device in your system.

In rewritable mode, Panasonic's drive accepts 2.6G or 4.7G DVD-RAM media,

and the media may be single or double-sided. To read or record the opposing

side of a disc, you must eject it and flip it manually.

The drive's peak performance is achieved only with the new 4.7G media.

When you use 2.6G discs, the drive halves its data transfer rate from 2.77

megabytes/sec to 1.39 megabytes/sec. This affects reads as well as writes,

so unless you plan to share a disc with a colleague who uses a first-generation

DVD-RAM drive, you should always use 4.7G media.

Panasonic's DVD-RAM driver software turns the DVD-RAM drive into a pair

of virtual Windows drives. The first drive emulates an ordinary CD-ROM reader.

When you insert a CD into the Panasonic drive, it appears in Microsoft Corp.'s

Windows Explorer under the first letter assigned to the drive (for example,

drive D). When you insert a DVD-RAM disc or cartridge, its contents appear

in Windows Explorer under the second drive letter (for example, drive E).

Only one of the drive letters can be active. The unused letter behaves as

though no media is in the drive.

Except for speed, working with DVD-RAM is similar to working with a

hard drive. You can copy, delete, rename and open files on DVD-RAMs using

standard Windows facilities. Windows applications see the DVD-RAM as a removable

hard drive. You cannot use Windows' formatting, defragmenting or media repair

(ScanDisk) tools on DVD-RAM, but Panasonic includes a set of utilities that

provide most of the functions of the banned Windows tools.

I ran a battery of performance and reliability tests on the LF-D211U.

The drive passed all the tests, with one significant catch: Its actual write

speed is only a fraction of the stated maximum. Panasonic's drivers perform

read-after-write checks (verified writes) to ensure that data is recorded

properly. Data written to a 4.7G disc should transfer at about 2.7 megabytes/

sec, but the verified writes reduce the speed to roughly 1.1 megabytes/sec.

Fortunately, the drive reads data at the media's full rated speed.

Roughly midway through my large file read/write tests (copying a 2G

digital video file), the drive began seeking wildly. The stepper motors

used to reposition optical lasers are extremely slow, and while the laser

is seeking, no data is read or written. The seek frenzy lasted about two

minutes, reducing data rates to near the level associated with floppy disk

drives, but then the drive returned to streaming data smoothly and silently.

Apparently, the Panasonic drivers replace bad sectors with alternate

sectors located at the edge of the disc. The Panasonic drivers should offer

users the option of skipping bad sectors instead of using the alternates.

That would allow continuous, smooth streaming of data. The issues that detract

from Panasonic's new DVD-RAM drive will be addressed by updated device driver

software.

You could wait until DVD-RAM hits its full potential as a video and

data medium, but I find second-generation DVD-RAM irresistible in its present

state. At $500, Panasonic's LF-D211U is a painless way to jump into DVD-RAM

technology.

Yager is a freelance journalist.