Go to TOP (7) What about 90-minute and longer CD-R discs?
Decades ago, CD-Rs were originally designed in the 63-64 minute size, like the old “optical” discs. However, in a few years the 74-minute 650MB capacity became the standard, and soon after that 80-minute became the most common CD-R. However, the data-length description built into each CD at the factory is 2 digits long. That means that theoretically the disc COULD be up to 99 minutes in runtime. Theory is one thing, but reality is another… CD discs are read starting at the center and moving out toward the edge of the disc in a spiral, as the disc turns on the drive. The reading is done by a small laser and photo-electric sensor mounted on an arm that moves from the center outward as the disc is read. Of course there is a limit to this outward motion; it has to stop somewhere. Some of the older drives were made with an arm that would only reach out to a distance that corresponds to about 76 or 77 minutes of motion from the center. Those old drives could not accept the newer 80-minute
