CD Burning with Mount Rainier

The Mount Rainier standard will bring drag-and-drop support for CD-RW right to your OS. When it does, kiss your floppy disks good-bye.

The 3.5-inch, 1.44MB floppy disk has been around for nearly 20 years now, and calling it long in the tooth is a serious understatement. Manufacturers are starting to see the low-capacity floppy disk drive as a waste of room in the case. Gateway, for example, recently offered $10 discounts on systems sans floppy disk drives.

Whats become nearly ubiquitous, on the other hand, is the recordable CD. CD-R and CD-RW media are stable now, and most PCs ship with CD-RW drives as standard fare or low-cost options. The problem is, you need special software to format and burn CDs. If CD writing worked as smoothly and effortlessly as disk writing, we could finally phase out the floppy.

That ideal is on the horizon. The Mount Rainier format ( is a standard for a true drag-and-drop file system for rewritable CDs—built into the operating system. Mount Rainier was promulgated last year by an industry consortium that includes HP (Compaq at the time), Microsoft, Philips, and Sony.

Windows XP supports drag-and-drop CD-R already, but Mount Rainier (known as CD-MRW) is finally gaining sway as a universal format for operating-system support of CD-RW drives. Besides offering native support for CD-RW, Mount Rainier lets you pop an unformatted disc into the drive and use it immediately. The system formats the disc in the background as you copy data to it. And theres more.

CD burning is a very popular way to store large amounts of data, but recordable media havent been trustworthy enough for critical backup applications. An optical disc may have bad spots on it, which cannot be written to or read from reliably. These spots are tracked and marked in a process called defect management. With previous generations of CD-RW products, the file system or driver software handled defect management. Mount Rainier requires that defect management be built into the hardware in a standard way, removing application and OS dependencies and making optical backup far more reliable.

To ensure smooth defect management, a CD-MRW drive writes a main defect table into the lead-in (outer-ring) area of the disc and also creates a copy in the lead-out (the innermost ring of the recording surface). As the disc is formatted, the drive identifies bad block addresses and enters them in the defect table. Known good blocks near the lead-out are tracked as well; they act as replacements for the defective areas. If the drive wants to write to one of the bad blocks, that data is written to a replacement block instead. The slight loss in disc capacity is offset by greater reliability.

To maintain backward compatibility, Mount Rainier builds on the current Universal Disk Format (UDF) file system used by rewriteable drives, but it improves the 64K block-addressing scheme current drives use. CD-MRW addresses 2K blocks of data—a more common scheme used in file system management—making it better suited to working with OSs. Moreover, Mount Rainier mandates exclusive use of MMC-2 (Multimedia Command Set 2)—a set of command extensions that controls the way optical devices interact with the PC. Current drives use command sets that are hybrids of MMC-1, MMC-2, and proprietary commands, which makes standardization difficult. Sticking with MMC-2 enables OS support across hardware from different manufacturers.

CD-MRW drives can read all other CD formats, but non-MRW drives need custom reader software to read MRW discs. Discs formatted for MRW sometimes include Easywrite, a reader application for Windows, so older drives can read CD-MRW discs properly.

So when will Mount Rainier come standard on your PC? On the hardware side, a number of CD-MRW–capable drives are already shipping, including the Yamaha CRW-3200 series and the Lite-On 48/12/48 drives. Though there have been no specific announcements of DVD+MRW drives yet, Philips has recently proposed an addition to the format that would offer the same defect management and other MRW capabilities to DVD+RW drives.

On the software side, the major operating-system vendors have all committed to the CD-MRW format. Native file system support will be built into future versions of Linux, Mac OS, and Windows (including Longhorn). There are no firm dates, however; the standard may not see support across all operating systems for some time. Optical-drive technology is progressing rapidly; when the hardware capability becomes widespread, perhaps the operating systems will follow.