Many different implementations of Disc-Based Enclosed Media (DBEM) have been developed over the previous decades; some achieved fairly high market share, while others barely made it to production. These devices range in size from just over an inch (~30 mm) to over 12 inches (~300 mm), with the smaller formats typically used for consumer electronics and home computers, while the larger formats were primarily utilized in medical, industrial, and other enterprise contexts. The below sections group the various formats based on the diameter of the inner recording medium, as is the convention.

Sub-90 disks have a recording medium with a diameter of less than 90 mm (3-1/2 in). These disks are mostly found in the consumer electronics and portable media industries, with some gaining wide appeal in their respective markets, while others faded into obscurity just as soon as they entered the market.

DataPlay

• The smallest commercial example of DBEM
• Total market failure with parent company going bankrupt the same year of release
• Very few devices utilized the format
• Only produced in a single capacity (500 MB) and only produced by one company (Imation)
• Outer Casing: 41 mm × 33.5 mm × 3 mm
• Phase-Change, Multi-session, and WORM

iD Photo

• Very small DBEM format focused on consumer camera market
• Market failure as they were quickly discontinued and only compatible with a single camera
• Only produced in a single capacity (730 MB)
• Outer Casing: 56.5 mm × 59.5 mm × 4.8 mm
• Magneto-Optical, Rewritable

Universal Media Disc (UMD)

• Fairly popular format, limited to early Sony PSP devices
• Partially enclosed casing, medium could be damaged if care wasn't taken with carts
• Single-layer (900 MB) and Dual-layer (1.8 GB) disks were produced
• Videogames, Movies, TV shows, and music videos were sold in the UMD format
• Outer Casing: 64 mm × 63 mm × 4.2 mm
• Pre-pressed, Read Only

MiniDisc (MD) Family

• Outer Casing: 70 mm × 67.5 mm × 5 mm

Of the different DBEM formats, 3.5 in (90 mm) was probably the most widely adopted in the consumer market. It did not see much use in Western countries, while it became relatively popular in some Asian markets (such as Japan). Cartridges have similar dimensions to a 3.5 in floppy disk, but they are about twice as thick. Capacities ranged from 128 MB to 2.3 GB across generations, and drives from the later generations were typically backward-compatible with earlier media. Both rewritable and WORM variants were produced.

The 5.25 in (130 mm) cartridge was the workhorse of professional and enterprise optical storage. Capacities grew from roughly 600 MB in early generations to 60 GB in the final iterations. The size supported rewritable MO, ablative and MO WORM, and phase-change formats. It was widely used in workstations, document imaging systems, and automated optical libraries (i.e., “jukeboxes”), where many cartridges were managed by robotics for enterprise archiving.

• Full Article — 12 in Disks

• The 2nd largest commercial examples of DBEM
• Many different manufacturers, formats, capacities, and recording technologies
• Typically for enterprise or medical facilities in the 1980s–1990s, with some examples still being produced in the 2000s

• Casing around ~13 in (330 mm) tall and wide
• May have large, metal shutter
• Material colors vary

• Outer Casing: ~330 mm × ~330 mm × ~20 mm
• Inner Media: 300 mm (12 inch)

• Various recording technologies
• Sometime rewritable, usually WORM