Ozone layer radiation was matched to only one known chemical, ozone. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958, Dobson established a worldwide network of ozone monitoring stations, which continue to operate to this day. The "Dobson unit", a convenient measure of the amount of ozone overhead, is named in his honor. The ozone layer absorbs 97 to 99 percent of the Sun's medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength),
Layer Jump Recording versa. Jumping layers is already necessary for reading multiple layer optical media (so far market released products are limited to two layers despite some research prototypes having up to eight layers), as well as for recording them with Sequential Recording. However the layer jump during the recording occurs only once, at the position called Middle Area, during a Sequential Recording, while it may occur multiple times with Layer Jump Recording. Two different Layer Jump methods are defined: Manual Layer Jump and Regular Layer Jump. The first require the software to specify to the hardware each jump point from layer zero