Microsoft has included built-in support for DVD devices in Windows operating systems since Windows 98 and Windows 2000, with driver support under the Windows Driver Model (WDM). All Windows versions up to and including Windows XP and Windows .NET Server support DVD video playback and DVD-ROM as an optical media storage device with these components: DVD class driver, WDM Stream class driver, UDF file system, copyright protection and regionalization, Microsoft DirectShow® navigator/splitter, proxy filters, video mixer, video renderer, and audio renderer. DVD writing capability can also be supported through the addition of third party software.
The next step for DVD support in Windows is to include built-in support for DVD write capabilities. Such support will allow, for example:
Easy backup of personal data.
Easy file transfer between PCs of multi-gigabyte files.
Easy transfer of video from a camcorder to DVD-Video for sharing with family, friends, and business associates.
To plan and develop built-in Windows DVD writing support, Microsoft is evaluating the available and future technologies and must determine which standard read/write format (or formats) to support.
Microsoft is concerned about the growing number of visually similar, but non-interchangeable DVD formats, because they will create considerable customer confusion. There have already been magazine articles and retail displays where the formats have been mislabeled. This confusion leads to reduced customer satisfaction and increased consumer frustration.
DVD writing encompasses three main activities: Backup, File Transfer, and DVD-Video creation. For the first two of these activities, the optimal user experience requires the media to support "drag and drop" style writing. For DVD, this capability is provided through Mt. Rainier-capable drives.
Why Mt. Rainier on DVD
Growing Industry Support. A growing number of manufacturers and OEMs are supporting Mt. Rainier-capable CD-RW and DVD+RW drives world-wide. This growing number of manufacturers plus the related reduction in prices indicate that Mt. Rainier-capable drives will be prevalent in the near future.
Best End-User Experience. The Mt. Rainier format provides the best end-user experience for backup of data and file transfer between PCs: It allows for "fast formatting" of media, making a disk available for drag-and-drop style writing approximately 30 seconds after unformatted media is inserted.
Drive Read/Modify/Write and Defect Management. The Mt. Rainier format allows writing to any sector on the media, in a 2K-sector size. The drive takes care of getting the data to the media. This technology allows for "floppy like" support, allowing for writing to any sector with full defect management capabilities and drag-and-drop behavior.
DVD-Video Compatibility. DVD+RW drives, which are currently the only DVD-writeable drives that support Mt. Rainier formats, can also create discs that are readable in most consumer DVD-Video players.
Built-in Support in Windows
Microsoft will focus its efforts on developing DVD writing support for Mt. Rainier-enabled drives and emphasize the technologies that promote those efforts. Because this technology is new, and because of the real-life user scenarios that are enabled by other functionality available, Microsoft will attempt to support additional capabilities in the next version of Windows, including the possibility of DVD-Video mastering on non-Mt. Rainier-capable drives.
According to current plans, user-mode interfaces to both the image mastering API and the burn-engine functionality will be available for use. This will allow ISVs to expand upon the built-in support and to add CD/DVD recording functionality to their applications without requiring a separate kernel-mode driver.
Issues under Consideration
Microsoft continually evaluates the technologies it supports in Windows. In addition to providing built-in support for Mt. Rainier-capable DVD drives, the following technical issues were also considered.
Unlike DVD+R/RW technologies, DVD-RW currently requires writes in 32K chunks, aligned on 32K boundaries. Because the sector size of the media is 2K, this causes significant problems for Windows cache manager and file systems. Furthermore, to write to packet N on DVD-RW media, packet N-1 must be written to first. This means that data must be written sequentially to be space efficient.
Compatibility with Consumer DVD-Video Players
A major motivation for buying a DVD-writeable equipped PC or drive will be the ability to create DVD videos. In addition to supporting the Mt. Rainier format, other supported technologies must offer good physical format compatibility with existing consumer DVD-Video players through either RW media or write-once media.
DVD+RW has roughly the same cross-media compatibility as DVD-RW, and DVD+R is expected to have roughly the same compatibility as DVD-R.