As CD-ROM speeds continue to increase, we are finding that traditional reading technologies are approaching apparent limits. CAV (constant angular velocity) reading technology dominates today's CD-ROM drives, yet the very nature of the technology imposes a performance ceiling. CAV readers work by maintaining a constant RPM (revolutions per minute) no matter what portion of the disc is being read. This means that in order to increase a drive's X rating, the RPM must be increased. Mechanical limitations in current technology have maxed out today's CAV readers at 56X. This equates to spin rates in the neighborhood of 12,000 RPM! Compare this to hard disk drive technology and we find that only Seagate's 15,000 RPM drive spins at a faster rate. Yet the engineering involved in making a sturdy, reliable hard drive far outshines what goes into a $70 CD-ROM drive. How much faster can CAV CD-ROM drives get and still maintain their dirt-cheap pricing?
We now examine one of today's fastest-rated CAV readers, Digital Research's 56X CD-ROM drive. According to the box, the model number is DRCDROM56. However, upon examining the drive, we found reference to the drive being made by a Chinese company, Top Glory Electronics, with a model number of BCD G621D. Further complicating matters is the drive's designation by our testbed's system bios and Windows 98's System Properties as "CD-ROM Drive/G6D." The bios revision of this drive is reported as 1.30.
We visited the website of Digital Research in order to glean some more information on this unit, but it appears the site has not been updated yet to include this drive. Our only source for the drive's specifications was the box it came in. Missing from the specs is the rated access time. What we do know is the drive includes a 128 kb buffer, "high speed data extraction" (more on this in our DAE section), and "anti-shock audio", which purports to keep CD audio playing smoothly in the event the drive is rattled. We chose not to test this out of concern for damaging either the drive or any other components in our testbed. This drive is readily available at Best Buy and other computer and office superstores for about $70. Finally, the drive is protected with a standard 1-year warranty.
Physically, the drive is of a non-standard size. The length from front to back is a full 1 3/16 inches shorter than the typical optical drive. This actually creates more room for cabling and airflow in most system cases. Another oddity on this drive is an unlabeled jumper block adjacent to the molex power connector. We emailed Digital Research tech support to ask about these and other issues, but as of today (one week after emailing), we've received no response.
Its environmental characteristics can be quite obtrusive. This is by far the loudest optical drive we've tested so far. With 12,000 RPM operation, noise levels approach unbearable for my ears. On the other hand, the drive barely gets warm to the touch even after extensive stress testing.
Let's now examine how this drive performs.