While CDs were still fighting for market share against cassettes, and gaming consoles were just starting to switch over to CD from cartridge storage, optical media companies were already thinking ahead. Only two years after the introduction of the original PlayStation, the DVD Forum had introduced the DVD-RAM standard: 2.58 GB per side of a disc in a protective caddy. The killer feature? Essentially unlimited re-writeability. In a DVD drive that supports DVD-RAM, they act more like removable hard drive platters. You can even see hard sectors etched into the media at the time of manufacture, giving DVD-RAM its very recognizable pattern.
At the time, floppy drives were still popular, and CD-ROM drives were increasingly available pre-installed in new computers. Having what amounted to a hard drive platter with a total of 5 GB per disc should have been a killer feature for consumers. Magneto-optical drives were still very expensive, and by 1998 were only 1.3 GB in size. DVD-RAM had the same verify-after-write data integrity feature that magneto-optical drives were known for, but with larger capacity, and after the introduction of 4.7 GB size discs, no caddy was required.