Mount Rainier (MRW) is a format for writable

optical disc In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc that encodes binary data (bits) in the form of pits and lands on a special material, often aluminum, on one of its flat surfaces. ...

s which provides the

packet writing Packet writing (or incremental packet writing, IPW) is an optical disc recording technology used to allow write-once and rewritable CD and DVD media to be used in a similar manner to a floppy disk from within the operating system. Details ...

and defect management. Its goal is the replacement of the floppy disk. It is named after Mount Rainier, a volcano near

Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

, United States. Mount Rainier can be used only with drives that explicitly support it (a part of SCSI/ MMC and can work over ATAPI), but works with standard CD-R, CD-RW, DVD+/-R and DVD+/-RW media. The physical format of MRW on the disk is managed by the drive's firmware, which remaps physical drive blocks into a virtual, defect-free space. Thus, the host computer does not see the physical format of the disk, only a sequence of data blocks capable of holding any

filesystem In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is Computer data storage, stored and retrieved. Without a file system, data placed in a storage me ...

. (Reference describes ''DVD+MRW'' too.)

Design

The time needed for the

disk formatting Disk formatting is the process of preparing a data storage device such as a hard disk drive, solid-state drive, floppy disk, memory card or USB flash drive for initial use. In some cases, the formatting operation may also create one or more ne ...

is shortened to about one minute by the background formatting capabilities of the drive. Formatting allocates some

sector Sector may refer to: Places * Sector, West Virginia, U.S. Geometry * Circular sector, the portion of a disc enclosed by two radii and a circular arc * Hyperbolic sector, a region enclosed by two radii and a hyperbolic arc * Spherical sector, a p ...

s at the end of the disk for defect management. Defective sectors are recorded at a table in the

lead-in A lead-in is a short phrase, usually five words or less, that starts off a photo caption in a newspaper, high school yearbook, magazine or other publication. Lead-ins (a.k.a. "kickers") are used to catch the reader's attention and "lead in" to t ...

(an administrative area) and in a copy of the table in the lead-out. From the host computer's perspective, an MRW disc provides a defect-free block-accessible device, upon which any host supported filesystem may be written. Such filesystems may be

FAT32 File Allocation Table (FAT) is a file system developed for personal computers. Originally developed in 1977 for use on floppy disks, it was adapted for use on hard disks and other devices. It is often supported for compatibility reasons by ...

NTFS New Technology File System (NTFS) is a proprietary journaling file system developed by Microsoft. Starting with Windows NT 3.1, it is the default file system of the Windows NT family. It superseded File Allocation Table (FAT) as the preferred fil ...

, etc., but the preferred format is usually UDF 1.02, as this file format is widely supported. An MRW-formatted CD-RW with a UDF filesystem gives approximately 500 MB free space. Mt. Rainier allows write access to a disc within seconds after insertion and spin-up, even while a background formatting sequence is taking place. Before this technology, a user would have to wait for the formatting to complete before writing any data to a new disc. It is even possible to read (but not write) MRW disks without an MRW-compatible drive; A "remapper" device driver is needed, an example of which is EasyWrite Reader for Windows. An alternative to MRW is to physically format a disc in UDF 1.5 or higher using the spared build. This is achieved by the use of specialized

software, or operating systems that support UDF versions 1.5 and above. MRW capabilities overlap somewhat with that of UDF 1.5+. Information about the exact format on disc is sparse. For a limited overview of the format on disc see.

Advantages

Advantages of MRW over UDF 1.5+ include: * fast background formatting of the media * finer grained packet size of 2K versus 64K * file system independence * does not depend on the host system to perform defect management Advantage of UDF 1.5+ over MRW include: * more portable, as UDF 1.5+ alone does not need specialized drive hardware to write, and the computer needs neither an MRW driver for a MRW-capable optical drive nor an MRW reader for drives that are incapable of reading MRW natively, reducing software overhead.

Operating system support

Mount Rainier is implemented natively in

Windows Vista Windows Vista is a major release of the Windows NT operating system developed by Microsoft. It was the direct successor to Windows XP, which was released five years before, at the time being the longest time span between successive releases of ...

and

Windows 7 Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was released to manufacturing on July 22, 2009, and became generally available on October 22, 2009. It is the successor to Windows Vista, released nearly ...

.{{cite web , url=http://www.quepublishing.com/articles/article.aspx?p=1746162&seqNum=6 , title=Upgrading & Repairing PCs: Optical Storage , last=Mueller , first=Scott , date=November 1, 2011 , publisher= Pearson Education , work=Que Publishing , access-date=June 18, 2015

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...

has built-in MRW support since

kernel Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine learn ...

version 2.6.2 (2004). Amiga OS4 supports this natively since the first beta appeared in 2004. Support for reading this format was also added to

Mac OS X macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and la ...

. Operating systems that don't support MRW natively (notably

Windows XP Windows XP is a major release of Microsoft's Windows NT operating system. It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. It is a direct upgrade to its predecessors, Windows 2000 for high-end and ...

and prior versions) need third-party software to read and write MRW-formatted discs, and these tend to be the same

utilities which allow native UDF filesystems to be written to optical media. Some optical disc software, such as IsoBuster, can support Mount Rainier on non-MR drives.IsoBuster featurews page
- ''"Support for Mount Rainier CD-RW and DVD+RW discs in MRW compatible and non-MRW compatible drives. Auto detection and automatic remapping which can be switched off or forced at all times. Built in MRW remapper / reader. (Built in Method 3 remapper)"'' The EasyWrite logo is the marketing symbol created by

Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...

for CD drives that are Mount Rainier compatible. CD-MRW stands for

Compact disc The compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. In August 1982, the first compact disc was manufactured. It was then released in Oc ...

– Mount Rainier Read/Write.

References

External links

Mount Rainier Support in Linux
SCSI Computer file systems Optical computer storage media