There are numerous formats of recordable optical direct to disk on the market, all of which are based on using a laser to change the reflectivity of the digital recording medium in order to duplicate the effects of the pits and lands created when a commercial optical disc is pressed.
This uses the laser alone to scorch a transparent organic dye (usually cyanine, phthalocyanine, or azo compound-based) to create "pits" (i.e. dark spots) over a reflective spiral groove.
Rewritable, non-magnetic optical media are possible using phase change alloys, which are converted between crystalline and amorphous states (with different reflectivity) using the heat from the drive laser.
High-bandwidth digital connections such as HDMI are unlikely to feature as recorder devices are not permitted to decrypt the encrypted video content.
When using rewritable media (CD-RW, DVD-RW, DVD-RAM), the UDF file system organizes the disc into packets that are written individually.
Features: SafeBurn is a proprietary technology for buffer underrun protection developed by Yamaha Corporation.
Several competing and incompatible packet writing disk formats have been developed, including DirectCD and InCD.
This feature allows for observing the writing speeds and patterns (e.g. constant angular velocity, constant linear velocity and P-CAV and Z-CLV variants) with different writing speed settings and testing the highest capacity of an individual disc that would be achievable using overburning.
[8] This feature is standardized on CD-R, CD-RW, DVD-R and DVD-RW, but not on DVD+R and DVD+RW, on which only Plextor optical drives support simulated writing so far.
The problem is exacerbated because as the writing laser of the recorder is used, its power output drops with age - typically after just a few years.
[11] A series of follow-up studies conducted by the Canadian Conservation Institute in 2019 revealed that CD-R with phthalocyanine-dye and a gold-metal layer had the greatest longevity at over 100 years when stored at ideal temperature and humidity-levels.
The researchers concluded the silver layer discs may not be a suitable solution for applications where longevity is important.