ISO 9660

When CD-ROM arrived in the mid-1980s, discs needed a file system every operating system could read. The industry first rallied around the "High Sierra Format" (1985, named after the hotel where the meeting was held), which ISO formalised as ISO 9660 in 1988. The standard is deliberately austere: short uppercase names, limited directory depth, everything pitched at the lowest common denominator.

Extensions loosened the straitjacket — Joliet for long Windows names, Rock Ridge for Unix permissions, El Torito for bootable discs. UDF later took over for DVD and recordable media, but ISO 9660 still sits on every pressed CD.