Sony is straddling the fence in the struggle over which DVD rewritable format will eventually dominate the market. The consumer electronics giant has begun shipping to retailers DVD+RW drives and discs, which should be available to consumers by the end of the month. At the same time, Sony is continuing to support competing DVD rewritable formats -- an unusual decision in the industry. Sony's move comes amid an ongoing donnybrook in the DVD rewritable market. There are several formats, including DVD-RW, DVD-RAM and DVD+RW, that are competing to become the industry standard. However, each format offers its own advantages and challenges. DVD-RW is mainly for people looking to record video and play it on consumer DVD players. But that format isn't as convenient for data storage as are DVD-RAM and DVD+RW, which allow drive owners to store data randomly, like a hard drive does. In addition, consumers can only record once per session with DVD-RW drives, meaning that if people want to add a video clip to others already on a disc, they must erase the entire disc and record all the video clips at once. DVD+RW discs can "essentially act like a big floppy," which is why Sony is supporting the format, Sony marketing manager Bob DeMoulin said this week. The support for DVD+RW from Sony, as well as from other major manufacturers such as PC makers Dell Computer and Hewlett-Packard, is a sign that DVD+RW is picking up momentum. But by no means is the debate over. "We're firmly behind +RW, and we believe it will be successful. But we're not so sure that its success doesn't mean that -RW won't be," DeMoulin said. "That's why we continue to support -RW." Gartner analyst Mary Craig said Sony's caution is warranted because DVD+RW still has two major hurdles to overcome: compatibility and supply. "Compatibility with DVD-ROM players will be a key issue for (DVD+RW), and the manufacturers will have to establish credibility with the market that they can supply (enough DVD+RW) drives," Craig said. Sony plans to continue supporting DVD-RW through its membership in the DVD Forum -- a group of hardware makers developing the DVD-RW, DVD-R and DVD-RAM formats -- and by selling and manufacturing the competing discs. Still, DeMoulin said the company does not plan to manufacture DVD-RW drives. Sony is also one of the key members of the DVD+RW Alliance, a group formed to develop and promote the format. The alliance includes Dell and HP. Some Sony Vaio PCs already come with DVD-RW drives from other manufacturers. That's only because the DVD-RW drives were available before DVD+RW drives, DeMoulin said. "Our PC guys had to add the technology for competitive reasons, and it was the right decision at the time," DeMoulin said. "But if DVD+RW drives were available at that time, I think there would be DVD+RW drives in those PCs now." Mark Hanson, Sony vice president of Vaio marketing, concurred that the PC division went with DVD-RW drives because at the time that was the only option. "We're continuing to evaluate -RW, and it is probably still the main option," Hanson said. "The key is whether or not people can burn and play content on a device." Such compatibility issues are less of a problem with DVD-RW than with DVD+RW, said Pioneer product manager Paul Meyhoefer. Pioneer is one of the major manufacturers of DVD-RW drives. "Being able to play video on most of the DVD players on the market is the key strength of DVD-RW," he said. Meyhoefer asserted that the vast majority of consumer DVD players can play DVD-RW discs. He added that the inability of DVD-RW to store data like a hard drive is a trade-off of the format. Sony's DRU110A/C1, the combination DVD+RW/CD-RW drive, will cost $599 when it reaches store shelves by month's end. It will record DVDs at speeds of 2.4x and read them at 8x. The DVD+RW discs will cost $16 each. HP already has a DVD+RW/CD-RW drive on the market and recently announced that its HP Pavilion 995 PC would come with a DVD+RW drive. Dell announced in late June that it would begin selling DVD+RW drives with its PCs this year, but the company has yet to do so.