摘要:
It is an object of the present invention to provide an information recording method for recording information in a data rewritable type optical recording medium having a plurality of information recording layers, which can form recording marks having good shapes. In the information recording method according to the present invention, information is recorded in an optical recording medium 10 having at least a stacked L0 layer 20 and L1 layer 30 by projecting a laser beam whose power is modulated thereonto via a light incidence plane 13a. When information is recorded, λ/NA is set to be equal to or shorter than 700 nm, where λ is the wavelength of the laser beam and NA is the numerical aperture of an objective lens for converging the laser beam, and a pulse width Ttop0 of a top pulse of the laser beam when information is to be recorded in the L0 layer 20 is set to be shorter than a pulse width Ttop1 of a top pulse of the laser beam when information is to be recorded in the L1 layer 30.
摘要:
It is an object of the present invention to provide an optical recording medium that is suitable for recording information therein at a high velocity. An optical recording medium according to the present invention includes a recording layer formed of a phase change material and capable of recording data therein at a linear recording velocity equal to or higher than 10 m/sec, wherein Rtop satisfies the condition that it is larger than {11−(V/5)} and smaller than {22−(2V/5)}, where Rtop (%) is a reflectivity of the crystal phase change material forming the recording layer and V (m/sec) is a target linear recording velocity. According to the present invention, since modulation (MOD) of 50% or more can be ensured, it is possible to effectively suppress the degradation of jitter caused by recording data at a high linear recording velocity equal to or higher than 10 m/sec.
摘要:
A tape drive apparatus employing a tape cassette including a solid-state memory in a cassette half unit that accommodates a magnetic tape. When recording application data on the magnetic tape, the application data is written in an area of a preset size of the memory, beginning from a leading end of the application data. In this manner, it is assured that the management information located at the leading end of the application data can be stored in the memory. In reproducing the application data from the tape cassette, the management information stored in the memory is exploited to save time in accessing the management information recorded on the magnetic tape.
摘要:
A mobile unit 10 is provided with a called party number acquiring unit 102 for acquiring a called party number corresponding to a call origination command entered by a user, a number checking unit 103 for checking the called party number acquired by the called party number acquiring unit 102, against every origination-restricted number stored in an origination-restricted number storing unit 112, and an origination restricting unit 104 for restricting origination of a call on the basis of the result of the checking by the number checking unit 103.
摘要:
It is an object of the present invention to provide a method for determining the power of a laser beam which can determine the recording power of the laser beam so that jitter of a reproduced signal obtained by reproducing data recorded in a data rewritable type optical recording medium can be controlled within a tolerance even when cross erasing of data occurs and that the reproduced signal having the highest level can be obtained. The method for determining the power of a laser beam according to the present invention includes the steps of recording a first test signal in a data rewritable type optical recording medium while varying a level of the recording power of the laser beam, measuring, for each of the levels of the recording power of the laser beam, an amplitude A0 of a reproduced signal obtained by reproducing the first test signal before the first test signal is influenced by cross erasing of data, an amplitude A1 and jitter J1 of a reproduced signal obtained by reproducing the first test signal after the first test signal was once influenced by cross erasing of data and an amplitude As and jitter Js of a reproduced signal obtained by reproducing the first test signal after an influence of cross erasing of data on the first test signal was saturated, calculating a first parameter for each of the levels of the recording power of the laser beam as a function of the difference between the amplitude A0 of the reproduced signal obtained by reproducing the first test signal before the first test signal is influenced by cross erasing of data and the amplitude A1 of the reproduced signal obtained by reproducing the first test signal after the first test signal was once influenced by cross erasing of data, calculating a second parameter for each of the levels of the recording power of the laser beam as a function of the difference between the amplitude A1 of the reproduced signal obtained by reproducing the first test signal after the first test signal was once influenced by cross erasing of data and the amplitude As of the reproduced signal obtained by reproducing the first test signal after the influence of cross erasing of data on the first test signal was saturated, calculating a third parameter for each of the levels of the recording power of the laser beam as a function of the difference between the jitter Js of the reproduced signal obtained by reproducing the first test signal after the influence of cross erasing of data on the first test signal was saturated and the jitter J1 of the reproduced signal obtained by reproducing the first test signal after the first test signal was once influenced by cross erasing of data, obtaining a value of the first parameter corresponding to a value of the second parameter when the third parameter is equal to a tolerance, thereby determining a critical parameter, recording a second test signal in the data rewritable type optical recording medium while varying a level of the recording power of the laser beam, judging whether or not signal characteristics of a reproduced signal obtained by reproducing the second test signal recorded in the data rewritable type optical recording medium satisfy reference conditions, measuring, for each of the levels of the recording power of the laser beam, when the signal characteristics of the reproduced signal obtained by reproducing the second test signal recorded in the data rewritable type optical recording medium satisfy the reference conditions, an amplitude AA0 of the reproduced signal obtained by reproducing the second test signal before the second test signal is influenced by cross erasing of data and an amplitude AA1 of the reproduced signal obtained by reproducing the second test signal after the first test signal was once influenced by cross erasing of data, calculating a fourth parameter based on the amplitudes AA0 and AA1 of the reproduced signals obtained by reproducing the second test signals as a function of the difference between the amplitude AA0 of the reproduced signal obtained by reproducing the second test signal before the second test signal is influenced by cross erasing of data and the amplitude AA1 of the reproduced signal obtained by reproducing the second test signal after the first test signal was once influenced by cross erasing of data, comparing the critical parameter and the fourth parameter, and determining the recording power of the laser beam at which the fourth parameter was obtained as an optimum recording power when the fourth parameter is equal to or lower than the critical parameter.
摘要:
A tape cassette of this invention is equipped with a memory capable of accommodating management information. The memory retains an MIC logical format type designating a format state, either formatted or unformatted, of the magnetic tape. A check is made on the consistency between the format state designated by the MIC logical format type and the format state estimated by reading data from the magnetic tape. If an inconsistency is detected, that is interpreted to mean that the tape cassette has been tampered with, and read and write operations on the cassette are controlled accordingly. This enhances security against fraudulent uses of a tape drive system loaded with the tape cassette.
摘要:
It is an object of the present invention to provide a method for recording data in an optical recording medium which can record data in a write-once type optical recording medium at a high linear recording velocity using a laser beam having a low recording power. The method for recording data in an optical recording medium according to the present invention is constituted so that when data are to be recorded in an optical recording medium including a substrate, a first recording layer and a second recording layer by projecting a laser beam whose power is modulated in accordance with a pulse train pattern including pulses whose levels are set to levels corresponding to a recording power Pw and a bottom power Pb onto the optical recording medium and forming a recording mark at a predetermined region of the first recording layer and the second recording layer, as a linear recording velocity increases, the power of the laser beam is modulated using a pulse train pattern including a smaller number of pulses whose level is set to a level to the recording power Pw, thereby forming a recording mark. According to the present invention, since the power of a laser beam is modulated using a pulse train pattern including a smaller number of pulses whose level is set to a level to the recording power Pw as a linear recording velocity increases, it is possible to record data in an optical recording medium using a laser beam having a low recording power even when a linear recording velocity is high and on the other hand, it is possible to prevent cross-talk of data from increasing even when a linear recording velocity is low. Therefore, it is possible to employ a semiconductor laser having a relatively low output even when data are recorded at a high linear recording velocity.
摘要:
In an optical recording medium comprising a phase change recording layer (4) containing Sb and optionally, Te and/or In as a main component, the recording layer is able to be crystallized to provide a crystallized region which contains rhombohedral crystals consisting essentially of Sb and is substantially free of a crystal phase other than the rhombohedral crystals. When the recording layer contains a rare earth element, Zr, Hf, Ti or Sn as an auxiliary component, the medium has a dielectric layer (31) composed of silicon oxide, silicon nitride, aluminum oxide, or a mixture of zinc sulfide and at least 30 mol % of silicon oxide, disposed contiguous to and in front of the recording layer (4) as viewed from the recording/reading beam incident side. The medium has a high transfer rate and improved thermal stability.
摘要:
A tape drive device including a tape driver for information recording or reproduction is performed on a magnetic tape when a tape cassette having the magnetic tape accommodated therein is loaded, a memory driver through which when a memory for recording management information to manage the recording or reproduction to the magnetic tape is provided to the tape cassette, read-out or writing of the management information from/into the memory can be performed, a detector for detecting storage capacity information of the memory which is stored in the memory, and an identifier for identifying the storage capacity of the memory on the basis of the storage capacity information.
摘要:
An optical recording medium of the invention comprises a phase change type recording layer on a surface of a substrate with reading light incident on the recording layer through the substrate, and a dielectric layer provided in contact with the recording layer and on a side of the recording layer on which the reading light is incident. The substrate has a groove acting as a guide groove and a land between adjacent grooves so that the groove and land are used as recording tracks. The phase change type recording layer contains Ag, In, Sb and Te as main components, and has a thickness tR defined by tR≦&lgr;p/20 where &lgr;p is a wavelength of the reading light. The dielectric layer has a thickness td1 that is represented in terms of an optical path length at the wavelength &lgr;p and defined by &lgr;p/2≦td1.