You may have heard of LIMDOW media. This is also referred to as "direct overwrite" media. LIMDOW stands for Light Intensity Modulation Direct OverWrite.

When using convential MO disks, in order for the drive to write a sector to disk, it erases the sector, writes the new data, and then verifies the just-written data. (You can enable or disable verification by using a DIP switch on the drive, or by sending the appropriate command to the drive from the computer.) This requires three revolutions of the disk.

With LIMDOW media and a LIMDOW-capable drive, the new data can be written with no need for the old data to be erased first. This means that writing speed is increased by about 50%. Without verification, writing speed would be almost doubled.

The down side to this is that, at least for the moment, LIMDOW media is more expensive than normal media.