Mt. Rainier originally came into existence through rewritable DVD's optical storage antecedent, CD-RW. Originated by CD co-licensor Philips, "The Mt. Rainier specification was developed in 2001 to provide the framework necessary for computer operating systems to seamlessly rewrite data CD-RW discs in a drag-and-drop fashion without the use of additional drivers or software," wrote EMedia contributing editor Hugh Bennett in an OSTA white paper titled "Understanding CD-R & CD-RW" (www.osta.org). Providing myriad "enhancements over the abilities of conventional packet-writing software," Bennett continued, Mt. Rainier improved disc interchange by supplying a non-proprietary standard and transformed disc-formatting into an automated, one-minute cakewalk.
Foremost among Mt. Rainier's enhancements, arguably, is recorder-based defect management, which checks optical discs for the degradation inherent to rewritable phase-change media over successive rewrites. It then reallocates space to compensate for the damage, thus keeping discs viable longer. "The drive has a better knowledge of what sectors might be wearing out and can determine with a lot more accuracy where a sector is going bad," says John Main, integrations architect for Hewlett-Packard and spokesperson for the DVD+RW Alliance. These spare sectors have space requirements between 132 and 516MB per disc depending on the amount used and rewritten. To top it all off, moving defect management from software to hardware frees up your CPU.
Now here's the rub. Putting defect management in the drive severely limits compatibility of Mt. Rainier-written DVD+RW discs on non-Mt. Rainier drives and DVD-Video players. While those constraints are not as severe as those involving DirectCD-written CD-RWs—which require the recording application's presence to play—restrictions remain. Older DVD+RW drives cannot read or overwrite a Mt. Rainier disc's data, while some legacy DVD+R/RW drives may be able to read it. If not, according to Main, "each disc has an area for a Mt. Rainier/UDF driver, or a URL where the driver can be downloaded, an ISO bridge," says Main. So until they go out and upgrade their OS and buy a new DVD+RW drive, most DVD+R/RW users will have to scroll through Mt. Rainier discs without the ability to interact with them. Which, in a sense, supports the "hard drive" analogy, since it effectively transforms DVD+RW discs from removable to fixed media.
The reason all the talk about Mt. Rainier today centers around DVD+RW and not the competing DVD-RW format—a very similar type of rewritable DVD—is because it only applies to DVD+RW drives. But DVD-R/RW does have an answer to Mt. Rainier's defect management scheme through its Distributed Real-Time Defect Management (DRT-DM). Andy Parsons, senior vice president of product development and technical support for Pioneer, explains: DRT-DM "avoids the use of bad sectors, but can optionally provide a way to simply skip over them rather than replacing them with spare sectors. It can be used for video applications because no time is used to locate a spare." Consequently, this method is ideal for streaming video applications.
Currently, DVD+R/RW doesn't offer much in the way of advantages over DVD-R/RW, depending on your view of the writable DVD market. As Parsons and Pioneer see it, "We think most users go out to buy a DVD writer to make discs that will play in DVD-Video players." Which camp offers greater compatibility with DVD-Video players is hard to say; in the absence of a comprehensive study that encompasses a matrix of media brands and players, the point remains moot. (A recent study noted in the news section of the DVD+RW Alliance's Web site puts DVD-R and DVD-RW slightly ahead.) What's clear so far is that both write-once versions (+R and -R), when recorded on PC drives, offer greater playback compatibility on DVD-Video players than their rewritable counterparts, which explains the "dash" camp's emphasis on write-once media.
The DVD+RW Alliance, by contrast, has emphasized rewritable capabilities from the get-go, and what DVD+RW will have once Mt. Rainier fully arrives is an environment in which transferring information to and from a DVD+RW disc will seem, as Main says, "as though you're simply using another hard drive." Also, DVD+RW's ability to do both streaming and random access (on specific drives that are so-equipped) could allow for dual-use DVD+RW discs, or discs which are partitioned to contain both conventionally recorded video files and data of various types and sizes transferred using Mt. Rainier. Main does temper enthusiasm by noting that such a disc would likely only function in a turnkey setup due to conflicting compatibility issues.
Complicating matters further (or simplifying them, depending on your perspective) is the spate of recent announcements of new drives supporting all four formats. Sony came first with its Dual RW units announced last fall, but the trend really picked up steam in May with the arrival of a subsequent Sony model plus multi-format drives announced by Verbatim and (more surprisingly) Pioneer, with its A06. Ostensibly, the companies made the move to simplify things for end-users, guaranteeing that the drives would (theoretically) write to any piece of media they bought. As Parsons says, "We've learned that many of the newest customers for DVD writers don't even know there's a format war going on, let alone understand the significance of a single punctuation mark on the product." At least Mt. Rainier support will come with a little more iconic reinforcement—an EasyWrite logo (kind of like a broken Slinky hovering over a compact disc) emblazoned on the front of the drive to designate certified write support for Mt. Rainier.
But the question of Mt. Rainier support throws another wrench in the works: which new drives will support Mt. Rainier, and for which media types? The latter question is answered fairly easily in the abstract (+RW), but that answer again puts the burden on the Mt. Rainier-inclined user to buy the right write media.
Further muddling matters (though certainly improving the perception of DVD-R/RW's long-term prospects) was another WinHEC announcement: While Microsoft promised exclusive support for DVD+RW earlier this year, they about-faced at WinHEC, announcing that they would support all things writable DVD in Longhorn. Microsoft support for DVD-RW doesn't mean Mt. Rainier support, but you can almost hear the same guy who called tech support because he bought the wrong kind of media saying, "You coulda fooled me…" All of which means Mt. Rainier may do little to reduce the volatility of the DVD format war. But what would you expect from a spec named after a live volcano?