Mount Rainier (MRW) is a format for writable

optical disc An optical disc is a flat, usuallyNon-circular optical discs exist for fashion purposes; see shaped compact disc. disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid o ...

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 Pa ...

and defect management. Its goal is the replacement of the

floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a ...

. It is named after

Mount Rainier Mount Rainier ( ), also known as Tahoma, is a large active stratovolcano in the Cascade Range of the Pacific Northwest in the United States. The mountain is located in Mount Rainier National Park about south-southeast of Seattle. With an off ...

, a volcano near

Seattle Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...

, Washington, United States. Mount Rainier can be used only with drives that explicitly support it (a part of

SCSI Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices, best known for its use with storage devices such as hard disk drives. SCSI was introduced ...

/ MMC and can work over

ATAPI ATAPI (ATA Packet Interface) is a protocol used with the Parallel ATA (IDE) and Serial ATA standards so that a greater variety of devices can be connected to a computer than with the ATA command set alone. It carries SCSI commands and responses ...

), 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 In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, h ...

, 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. (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 new f ...

is shortened to about one minute by the background formatting capabilities of the drive. Formatting allocates some sectors at the end of the disk for defect management. Defective sectors are recorded at a table in the lead-in (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 and was the default file system for the MS-DOS and Windows 9x operating systems. Originally developed in 1977 for use on floppy disks, it was adapted for use on ...

NTFS NT File System (NTFS) (commonly called ''New Technology File System'') is a proprietary journaling file system developed by Microsoft in the 1990s. It was developed to overcome scalability, security and other limitations with File Allocation Tabl ...

, 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 In the context of an operating system, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabli ...

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, released five years earlier, which was then the longest time span between successive releases of Microsoft W ...

and

Windows 7 Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was Software release life cycle#Release to manufacturing (RTM), released to manufacturing on July 22, 2009, and became generally available on October 22, ...

.{{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 Pearson Education, known since 2011 as simply Pearson, is the educational publishing and services subsidiary of the international corporation Pearson plc. The subsidiary was formed in 1998, when Pearson plc acquired Simon & Schuster's educatio ...

, work=Que Publishing , access-date=June 18, 2015

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

has built-in MRW support since kernel 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, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

. 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 successor to Windows 2000 for high-end and business users a ...

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. (), simply branded Philips, is a Dutch multinational health technology company that was founded in Eindhoven in 1891. Since 1997, its world headquarters have been situated in Amsterdam, though the Benelux headquarter ...

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

Compact disc The compact disc (CD) is a Digital media, digital optical disc data storage format co-developed by Philips and Sony to store and play digital audio recordings. It employs the Compact Disc Digital Audio (CD-DA) standard and was capable of hol ...

– Mount Rainier Read/Write.

References

External links

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