The smallest commercial example of Disc-Based Enclosed Media (DBEM) is the DataPlay disk. Introduced in 2002 by DataPlay, 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) on a 32 mm disc.

Their built-in DRM support and ability to ship with pre-recorded data 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 difficult market to enter.

Founded in November 1998 by Steve Volk, DataPlay Inc. was poised to develop a small, portable optical disc for downloadable music and other digital media¹⁾. In preparation of serving the Asian market, DataPlay Inc. and Toshiba established a joint-venture company named Japan DataPlay Inc. in October 2000²⁾³⁾. While there was some talk of DataPlay since the company's founding, the format gained public attention at CES 2001 in Las Vegas, NV. where it won a Best in Show award.

DataPlay had secured commitments from BMG, Zomba, Universal and EMI, and the company was positioning the format heavily around prerecorded music and DRM⁴⁾. One of the music albums promoted at CES was stated to have additional music content on the disk, but it would be encrypted and locked behind an additional paywall⁵⁾. The expected release date was initially April 2001, but this was delayed to Fall 2001, citing issues with production of the optical engine⁶⁾. This target too, was missed, and the format eventually launched in 2002. A limited number of pre-recorded albums released and DataPlay drives were incorporated into some consumer devices. However, competing technologies — particularly flash memory, the CD, and portable MP3 players — continued to gain marketshare.

DataPlay filed for Chapter 11 bankruptcy in 2002 and shut down operations that October, after reportedly spending approximately $120 million during its four-year operation. Only the 500 MB variant of the disks ever made it to market while larger capacities were planned by both DataPlay Inc. and its later owners⁷⁾.

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 in 2003 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 some members of its engineering team and their relationships with suppliers.⁸⁾.

In October 2004 during Ceatec Japan, DPHI executives stated that the format would return to the consumer market at about half of the original price-per-disk — $4.50 instead of the original $10 for 500 MB — and that new devices are in development to support the use of DataPlay disks as general storage devices, ditching the proprietary DFS for the FAT file system⁹⁾.

The 32 mm (1-1/4 inch) phase-change, optical disc was housed inside of a translucent and brightly-colored cartridge¹⁰⁾ with dimensions of 41 mm × 33.5 mm × 3 mm¹¹⁾.

One of the only devices to feature DataPlay disks was the iMP-350 SlimX, developed by the Korean company iRiver. This player was rather expensive at ~$350 and showed off a design language reminiscent of its time; complete with translucent plastic, chrome accents, and “futuristic” aesthetic¹²⁾. More manufacturers planned to produce readers and players for the format, but information about most of these models is scant.

The patents for DataPlay discs¹³⁾¹⁴⁾ 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.

Rating: Endangered

As of now, there are no official channels in which to purchase DataPlay disks, readers, or players and all have been out of production for over two decades. The only eBay listings I could find for NOS disks¹⁵⁾ and optical engines¹⁶⁾ ship from Italy. I have no doubts that the disks are functional if one has a working reader, but the optical engines are bare units with only an undocumented ZIF connector, so testing them would require some electronics engineering. I have yet to see a DataPlay player or pre-recorded disk eBay, so its safe to assume they're exceedingly rare, thus making this format difficult to interface with.

Update: The 21x disk packs (63x disks total) I received from this seller had moldy paper inserts. If you attempt to purchase these, be sure to have the seller send a photo before shipping.