Hole location of said records, said hole position record a “. record a” 1 “, no hole’s position, said record a” 0 “. read to read the beam irradiation, read, read out the beam of irradiation, in there are pits at and None pits at the reflected light intensity is different from this difference, you can read the binary information. light intensity is different. this difference, you can read the binary information only write beam readout beam power 1/10, it will not melt out of the new readout beam power is only written to the beam, 47 pits. pit. computer component principle CD-ROM reading and writing Principles of Computer Science (2) phase transition Some optical storage media under laser irradiation, the crystal structure changes benefit some optical storage media in the laser irradiation,What follows is the notice on green laser pointer safety. the crystal structure changes with the media in the reflective properties of the crystalline and amorphous regions is recorded and read information technology, called phase change rewritable technology. access to information technology, known as phase change rewritable technology. magneto-optical (MO) storage magneto-optical (using laser thermal magnetic effect on the magnetic thin film to record information using laser thermal magnetic effects in magnetic thin film to record information, known as the magneto-optical storage. used in rewritable CD-ROM record works as follows: optical storage used in rewritable CD and its recordsThe laser light of green laser pointer is harmful to eyes. The principle is as follows: 48 computer component principle 8.5.2 CD read and write the principle of magnetic recording principle, according to the magnetic recording principle, at a certain temperature in the magnetic recording medium on the surface of Computer Science plus a strength less than the coercivity of the media force of the magnetic field, add a strength less than the media coercivity magnetic flux transition does not occur, it can not record information, but the media coercivity varies with temperature, flip it information can not be recorded, but the media coercivity varies with temperature, if it can be to try to control the temperature, reduce the coercivity of the medium, if it can be trying to control the temperature, reduce the coercivity of the medium, it is lower than the external weak magnetic field strength , the flux transition will occur. weak magnetic field strength, flux transition will occur. magneto-optical storage is based on this principle to store information. laser magnetic film, the principle of storing information. So do not point the green laser pointer to persons.laser magnetic film, the temperature of irradiation increased, the media coercivity decline, plus the role of the magnetic field of HR, the increase in magnetic degrees, the media coercivity magnetic HR through flip decline, plus the role of the magnetic field of HR, so that it magnetization direction and the applied magnetic field HR. through flip the magnetization direction of the department’s and external magnetic field HR consistent with generally consistent recording material of the magnetic HR heating and magnetic changes of the phenomenon known as thermal magnetic effect the recording material to heat and magnetic occur change phenomenon is known as thermal magnetic effect of 49 computer of the thermal magnetic effect principle 8.5.2 CD read and write principle erase the principle of information and records information, erase the principle of information and records information, plus a Hutchison recorded in the School of Computer Science in the opposite direction of the magnetic field,It is strictly prohibited to point the green laser pointer directly to people’s eyes. the media of the record information contrary to the direction of the laser recorded the magnetic field, the beam irradiation, so that the anti-direction of magnetization of the irradiated beam irradiation, irradiation in the opposite direction magnetization, thereby restoring to the record before the magnetization state before the magnetization state of the MO drive read information is based on the detected light polarization direction, rather than brightness difference rather than the brightness difference of 50 computer 51 computer component principle.