Optical Disc Authoring - Process

Process

To burn an optical disc, one usually first creates an optical disc image with a full file system designed for the optical disc, and then copies the image to the disc. The disc image is a single file, built and stored on the hard drive, which contains all the information to be contained on the disc.

Most optical disc authoring utilities create a disc image and copy it to the disc in one bundled operation, so that end-users often do not know the distinction. However, a useful motivation for learning this distinction is that creating the disc image is an expensive (time-consuming) process, while copying the image takes relatively little time.

After copying a disc image, most disc burning applications silently delete the image from the Temporary folder in which it was built. Users can override this default, instructing the application to preserve the image. The existing image can then be used for creating further copies, rather than needing to be rebuilt each time.

There are also packet-writing applications that do not require writing the entire disc at once, but allow writing different parts at different times. This capability allows a disc to be constructed incrementally, as it could be on a rewritable medium like a floppy disk, subject to the limitation that a given bit on a non-rewritable disk can be written only once. Due to this limitation, a non-rewritable disc whose burn failed for any reason cannot be repaired. Such a disk is colloquially termed a "coaster".

There exist many optical disc authoring technologies for optimizing the authoring process and preventing errors. Some programs are able to mount a disc image as a file system type, so these images appear as actual mounted discs. This feature can be useful for testing a disc image after authoring but before writing to the disc media.