PC Hardware in a Nutshell, 3rd Edition

CD-Recordable (CD-R) Drives and Media

Although CD-R drives are passé, CD-R technology itself, as implemented in CD-(M)RW drives, remains important. CD-R devolved in spirit from Write Once/Read Many (WORM) drives that were developed in the early 1980s and were popular in data centers from the mid-`80s until better means of permanent storage became available. WORM drives were so called because they used a relatively high-power writing LASER to make irreversible physical changes to the disc in write mode, and a low-power LASER (or the same LASER operating at lower power) to read the disc. CD-R works on the same principle.

CD-R technology is based on the Orange Book standard that was developed in the late 1980s and has since been updated, expanded, and split to standardize support for such functions as rewritability and other developing technologies. Philips released the first CD-R drive in 1993. It was extremely expensive, wrote at only 1X, and used $50 CD-R discs made by Taiyo Yuden.

Although they must function interchangeably with standard pressed CDs in CD-ROM drives and CD players, CD-R discs have a different structure. Like pressed CDs, the label side of a CD-R disc is typically printed on a scratch-resistant and/or printable coating that resides on a base of UV-cured lacquer. The next layer is a reflective backing against which the reading LASER impinges. This reflective layer may be gold, silver, or a silver alloy, depending on the brand and model of CD-R disc.

As with a pressed ...