When we regularly carry around devices containing tens or hundreds of gigabytes of data, it’s sometimes a shock to remember that there was a time when 650MB on a CD was really, really big. These now archaic storage media first appeared as silver pre-recorded CD-ROMs and later as recordable CD-Rs. Most people eventually owned CD burner drives, and some more sophisticated ones had the ability to burn images into unused portions of the disc.
You don’t have a sophisticated drive and want a burned CD-R? Carefree, [arduinocelentano] has a solution, in software that writes a disk image for a standard CD burner whose data makes the image visible on the disk.
CD-Rs have a thin layer of phthalate dye sandwiched between the polycarbonate disc and a layer of silver lacquer. They are often gold in color, but the silvering is actually just aluminum. The data is encoded as a series of pits and lands hollowed out by the laser vaporizing small portions of dye to make holes.
The code creates a data structure of a standard CD-ROM session that contains no usable data, but whose pits and grounds are arranged to form the image. You can find everything in a GitHub repository and try to create your own offers. We would have made a Wrencher disc for our photos, but unfortunately for some of us who were once in the thick of things, we no longer have CD-Rs.