One of the smallest commercial examples of Disc-Based Enclosed Media (DBEM) is the DataPlay disk. Introduced in 2002 by DataPlay, Inc. (Later DPHM, inc.), DataPlay disks were intended to compete with the budding flash-based memory card market by offering a large capacity (250 MB per side, 500 MB per disk) in a small form-factor.

Their proprietary file system — DataPlay File System (DFS) — and support for DRM helped them gain initial interest in the portable music industry, but the prevalence of CDs and the recent release of portable MP3 players made this a tough market to enter.

DataPlay Inc. was founded in Colorado in 1998 by Steve Volk to develop a small, portable optical disc for downloadable music and other digital media. The disks stored 250 MB per side and could contain pre-recorded content, user-recorded data, or both. The format attracted industry attention, winning a CES Best of Show award in 2001, and incorporated an elaborate digital rights management system that allowed additional content to be unlocked after purchase. It was intended in part to address concerns about digital piracy that had intensified in recent years.

The format launched commercially in 2002, with a limited number of pre-recorded albums released and DataPlay drives incorporated into some consumer devices. However, the business struggled as consumers resisted the format's additional content fees and competing storage technologies — particularly flash memory and rewritable media — continued to gain marketshare. DataPlay filed for Chapter 11 bankruptcy in 2002¹⁾ and shut down operations that October, after reportedly spending approximately $120 million during its four-year operation.

The company's assets were subsequently targeted by DPHI Acquisitions Inc., a joint venture of Almon Ventures and Hexagon Investments, which offered $1.5 million to acquire the business and revive it on a smaller scale. The proposal, led by storage-industry executives Bill Almon Sr. and Bill Almon Jr., included DataPlay's intellectual property and optical storage technology. The reorganized company planned to focus on business applications and portable storage rather than the original consumer market, while retaining members of its engineering team and relationships with suppliers. DataPlay operated on a much smaller scale, pursuing licensing and niche storage applications rather than reviving the original consumer format²⁾.

The 32 mm (1-1/4 inch) phase-change, optical disc was housed inside of a translucent and brightly-colored cartridge³⁾ with dimensions of 41 mm × 33.5 mm × 3 mm⁴⁾.

The patents for DataPlay discs⁵⁾⁶⁾ describe a method for emulating a read/write file system on a WORM optical disc using multiple write sessions, similar to a CD-R. The disc contains a writeable area that is used from both ends simultaneously: file content (the actual data of files) is written inward from one boundary, while “system sectors” — blocks of metadata describing the files' names, sizes, and locations — are written inward from the opposite boundary. As more files are added, these two regions grow toward each other, with the boundary between them shifting depending on whether the disc holds many small files or a few large ones.

Because the medium cannot be erased, any change to a file — adding, renaming, or deleting it — cannot modify existing data. Instead, the system generates a new, updated system sector containing the current metadata and writes it to a location that will be read before any previously written system sectors. Older sectors remain physically present but are effectively superseded. Each system sector consists of a header (identifying the sector type, entry count, and next available identifiers/block locations) followed by a series of tagged entries, each describing one file or directory object, including pointers to its content, size, and relationships to other objects.

To locate a file, the drive reads system sectors starting with the most recently written one and checks whether it references the desired file. If found, that reference is used and reading stops. If not, the drive proceeds to progressively older sectors until the file is located or all sectors are exhausted. This “most recent wins” approach lets the drive present an accurate, up-to-date view of the file system — including files marked as deleted — despite the underlying inability to erase or move any data once written.