Optical drives

By J.B. MilesSpecial to GCNIn a couple of years, rewritable DVD drives with multiple gigabytes of storage likely will take over the desktop optical drive market. But for now there is still a lot to be said for 650M CD-RW drives.A CD-RW drive gives you three drives for the price of one. As a CD-ROM reader, it can read data and play commercially produced CDs. As a CD-R writer, it lets you create your own CDs, provided you use nonerasable CD-R disks. As a CD-RW rewriter, it lets you to write and rewrite data onto a single 650M disk for safe archiving.The price is well within the comfort zone, too. You can buy a good drive for less than $200. CD-R disks cost as little as 50 cents each; rewritable disks are about $3 each.CD terminology can be confusing, so it helps to begin with a brief compact disk glossary.CD-ROM'compact disk/read-only memory'drives run circular, reflective optical disks that hold 650M of data. That's enough to contain about 250,000 pages of text, up to 20,000 small, medium-resolution images and hundreds of multimedia audio and video files.CD-recordable drives represent the next generation of CD technology. They also use 650M disks, but unlike CD-ROM, these disks may be written to, though only once. The CD-R drive heads create the equivalent of pits in the optical surface of the disk by changing the reflectivity of certain dye layers within the disk. The advantage of CD-R technology is that virtually any CD-ROM reader can read a CD-R disk.CD-rewritable drives represent the third generation of CD technology and can perform both CD-ROM and CD-R functions. These work with erasable disks that may be rewritten up to 1,000 times.CD-RW disks must be formatted before they can be used. Most systems use the CD Universal Disk Format that provides for various types of formatting. One type of formatting allows packets of data to be written, appended and deleted, in a process similar to that used with hard and floppy magnetic disks. The reflectivity of the optical disk's surface may be changed repeatedly, but not permanently, as with CD-R.CD-RW drives may look similar, but they aren't. Factors that separate the average from the excellent include: Because of the three distinct functions of CD-RW drives, their speeds are listed with three ratings, generally expressed as write, rewrite, read, such as 4X/4X/32X. For example, the speeds of Hewlett-Packard's CD-Writer Plus 9210e are 8X for write, 4X for rewrite and 32X for read.The X is used universally among manufacturers and is based on the speed of the original audio CD drives. A playback speed of 150 kilobytes/sec is 1X.As CD technology spread, the need to increase speeds increased by a factor of two. A 2X device can read data at 300 kilobytes/sec, a 4X at 600 kilobytes/sec, an 8X at 1.2 megabytes/sec, and so on.The latest generation of CD-RW devices can write at 8X, rewrite at 4X and read at 32X, or 4.8 megabytes/sec.To translate the speeds into the time it takes to write 650M of data onto an optical disk, start at 74 minutes for 1X and divide by the X rating: a 2X drive takes 37 minutes, a 4X takes 18.5 minutes, and so on.Take note, however, that write times can vary according to the type and complexity of data being written. The two most popular interfaces for CR-RW drives are SCSI and Enhanced IDE. Both are common, although EIDE is less expensive and generally easier to implement than SCSI. EIDE interfaces generally only allow the attachment of internal CD-RW drives, but they are compatible with the AT Attachment Packet Interface specifications. ATAPI compliance permits a single interface for CD-ROM, CD-RW and tape drives, eliminating the setup woes often associated with these devices.Universal Serial Bus. USB is a hardware interface for low-speed peripherals that supports MPEG-1 and MPEG-2 digital video. The slow maximum bandwidth of 12 Mbps for USB specification 1.1 limits its usefulness in the CD-RW drive arena; most of the USB drives listed in the accompanying table have top read speeds of 6X.USB interfaces make use only of Microsoft Windows 98 and 2000 operating systems, another limitation for many users. A major benefit of USB, however, is that the standard encourages the attachment of external CD-RW drives.USB's hot-swap capability allows drives and other peripherals to be plugged in and unplugged without shutting down the computer.Industry watcher Cahners In-Stat Group of Scottsdale, Ariz., expects that the new USB 2.0 specification, expected later this year with an astounding 490-Mbps throughput, will by 2002 become the interface of choice for most PCs and peripherals.The IEEE 1394 standard, also called FireWire, is a high-speed data transport interface that will compete with USB 2.0 for high-bandwidth applications, such as digital video editing, and connections to consumer electronics equipment, such as DVD-ROM. Its future with CD-RW drives remains to be seen, although some manufacturers, including Addonics Technologies Inc., Granite Microsystems, LaCie USA, Pinnacle Micro and Yamaha Corp. of America, have included the FireWire interface with some of their portable products. The PC Card interface is used by a handful of CD-RW drive manufacturers for connecting portable drives to notebook PCs. EXP Computer Inc. and Micro Solutions Inc. offer PC Card and parallel port options with many of their portable drives. Be aware, though, that parallel port connections can be painfully slow. Just about all of the CD-RW drives listed in the table support most versions of Windows, with a handful supporting Linux and MS-DOS. Systems with USB and FireWire interfaces are often able to support Mac OS as well. But remember that, as a rule, USB and FireWire won't work with Windows 95 and NT. There is no difference in how internal and external CD-RW drives function. But external, portable units are a tremendous advantage to road warriors or users whose PC drive bays are already full.Another advantage is that you don't have to open a computer's backplane to use an external CD-RW. Just plug it into your USB or PC Card slot, turn it on, start your setup software, and you're up and running in minutes. You can expect to pay more for this flexibility, but it's often worth it. Most of the CD-RW drives in this guide come with a 2M data buffer; a few with 4M. Buffers are reserved segments of memory that hold data as it is processed, helping speed the write/rewrite/read process. The idea of making your own CDs can be daunting. But the job is made fear-free if your CD-RW drive comes with software such as Easy CD Creator 4.0 from Adaptec Inc. of Milpitas, Calif., or Nero Burning ROM 5.0 from Ahead Software of Karlsbad, Germany.Easy CD Creator 4.0 is extremely user-friendly and is bundled with most of the CD-RW drives listed in the table. The program allows you to select music from any recorded source, digitally filter any unwanted noise and then record it to CD. Ahead Software's Nero Burning ROM 5.0 is a high-end program bundled with many CD-RW drives. It isn't as simple to use as Easy CD Creator, but it comes with some nifty features, including: CD Text, which writes the artist and track titles to the CD; Audio Index, which inserts markers into an audio track; Pause time, which sets the pause time between tracks, and Filters, which cleans up audio tracks and reduces hiss. The program also supports MP3 files.XXXSPLITXXX-XXXSPLITXXX-XXXSPLITXXX-By J.B. MilesYou see a lot more hype about rewritable DVD technology than you do about CD-RW, which is not surprising when you consider all the people who want digital movies.The market for CD-RW exists mostly outside of the home movie market, but when rewritable DVD technology matures, it will likely present a serious challenge to CD-RW. For now, though, rewritable DVD formats'DVD-RAM, DVD+RW and Multi Media Video File'must contend with serious hurdles of compatibility, availability and price.A CD-RW drive can read, write and rewrite disks that are compatible with almost any CD technology. A rewritable DVD drive can read many, but by no means all, CD disks. Conversely, a disk written by a DVD-RAM drive could have trouble being read by CD drives.To date only a handful of DVD-RAM drives are for sale, many of which are priced above $600. You can find a lot of good CD-RW drives for under $200.Rewritable DVD has an edge over CD-RW in capacity. The various formats for DVD can hold anywhere from 2.6G to 5.6G per side. That's a lot of storage, and when DVD finally allows you to burn a music disk that can be read by a conventional CD player, the technology could well take over the marketplace.