Which company developed the CD-ROM format?

A CD-ROM (compact disc read-only memory) is a pre-pressed optical compact disc that contains data. Computers can read (but not write to or erase) CD-ROMs, i.e. it is a type of read-only memory.

The CD-ROM format was developed by Japanese company Denon in 1982. It was an extension of Compact Disc Digital Audio, and adapted the format to hold any form of digital data, with a storage capacity of 553 MiB.

Denon is a Japanese electronics company that was involved in the early stages of development of digital audio technology, while specializing in the manufacture of high-fidelity professional and consumer audio equipment. For many decades, Denon was a brand name of Nippon-Columbia, including the Nippon Columbia record label. The Denon brand came from a merger of Denki Onkyo and others in 1939. In 2001, Denon was spun off as a separate company with 98% held by Ripplewood Holdings and 2% by Hitachi. In 2002, Denon merged with Marantz to form D&M Holdings. On March 1, 2017, Sound United LLC completed the acquisition of D+M Holdings.