摘要:
An information recording/reproducing apparatus for recording information on and/or reproducing information from a recording medium using a head. The apparatus includes a single processor and a memory device. The single processor executes data input/output processing and servo processing of a light beam from the head, while alternately switching at a predetermined period. The servo processing is divided into a plurality of blocks which are cyclically executed in turn for each predetermined period and processing required to be executed in each period is set in each block and processing not required to be executed in each period is set in only a specific block. The memory device stores contents of the processing for the respective blocks.
摘要:
There is disclosed a network status server for receiving an inquiry from a web server accessed by a client, and using path information and determining the optimum web server to return a response to the accessed web server. The web server receiving the response instructs the client to access the optimum web server from the next time. In this constitution, accesses among the dispersed/arranged web server sites are leveled, and access loads can be leveled even among the web servers in the respective web server sites. Moreover, the client can access the optimum web server.
摘要:
In an information recording/reproducing apparatus, a head is moved across tracks on a recording medium to thereby perform a coarse seek to a position near a target position. A recording/reproducing portion of the head is moved in the track intersection direction to thereby perform a fine seek to the target position. A moving velocity of the portion of the head with respect to the medium is detected by a first detector. A target moving velocity is caluculated in accordance with a remaining distance to the target position of the portion of the head. A moving displacement or moving velocity of the portion of the head is detected by a second detector. A detection value from the first detector is corrected on the basis of a detection value from the second detector to eliminate a variation component generated by a disturbance of the portion of the head.
摘要:
Input/output processing of information is controlled in a magnetooptical disc apparatus for recording and/or reproducing the information on a magnetooptical recording medium by irradiating a desired track of the recording medium with a light beam via an optical system. The servo control of the light beam such as tracking servo control, focusing servo control or the like is performed by causing interruption in the input/output processing control. When the apparatus activates, a parameter in the servo control is set on the basis of a reproduction signal amplitude of the information with a change in state of the servo control and a parameter in signal processing of the information is set in accordance with a reproduction signal amplitude of the information corresponding to the set parameter for the servo control.
摘要:
An automatic loop gain control apparatus in a servo control apparatus of a closed loop arrangement which positions a control object with respect to a reference. The apparatus includes an adder for adding a reference signal of a predetermined frequency to a control signal in the closed loop, a first detector for detecting a peak value of predetermined frequency components of the control signal in a state before the control signal is input to the adder at every predetermined cycle, a second detector for detecting a peak value of predetermined frequency components of an output output from the adder at every predetermined cycle, and a digital signal processor for performing a digital computation using the peak value detected by the first detector and the peak value detected by the second detector and for adjusting the gain of the control loop on the basis of the result of the computation.
摘要:
The present invention provides an optical information recording and reproducing apparatus wherein a light beam spot is properly illuminated onto a recording medium by detecting a tracking error signal and/or a focus error signal in a time shared mode and by activating a tracking actuator and/or a focus actuator, thereby performing the recording and reproducing of information. The apparatus of the present invention includes a device for approximating an error signal on the basis of a plurality of error signals previously detected, when an error signal cannot be detected during an error signal detecting operation.
摘要:
An apparatus for recording and/or reproducing information with respect to a disk-like recording medium having a recording surface divided into a plurality of concentric circular zones each including a plurality of tracks with an address recorded thereon at an angular velocity or frequency varying with the individual zones, includes, a device for scanning the tracks for recording and/or reproducing information, a device for detecting an address of a track being scanned by the recording and/or reproducing device, a device for shifting the recording and/or reproducing device from a track being scanned to another track, and a control device for determining, if an address of a desired track cannot be detected when accessing the desired track during shifting of the recording and/or reproducing device to a zone different from a zone to which the desired track belongs, and shifting, as a result, the recording and/or reproducing device to a different track.
摘要:
An information recording and/or reproducing apparatus includes an optical system for irradiating a light beam to one of tracks arranged in parallel on a recording medium, an actuator for moving the optical system across the tracks, a circuit for alternately applying a jumping signal and a braking signal of the opposite polarity to the actuator to direct the light beam to a desired track, a tracking signal detector for intermittently sampling a tracking error signal varying between a positive value and a negative value with the movement of the optical system across the tracks, a memory for storing the sampled signals, and a switching timing detector for multiplying or adding the sampled signal and the previously sampled signal stored in the memory and causing the signal application circuit to switch from the jumping signal to the braking signal when the product or sum is zero or negative.
摘要:
An information recording-reproducing method is disclosed. An error correction code of M bytes and N bytes is imparted in a vertical direction and a horizontal direction, respectively, to data of m.times.n bytes. A signal of (m+M).times.(n+N) bytes (m, n, M and N being one or an integer greater than one) is produced. The signal to which the error correction code has been imparted is written-in to a recording medium. The written-in signal is read out from the recording medium. Error correction on the read-out signal is effected in only one of the vertical direction and the horizontal direction by the use of the error correction code included in the signal. A determination is made of the occurrence of abnormality in the writing-in when all the errors in the signal cannot be corrected by the error correction in the one direction. The signal for which has been determined that no abnormality exists in the writing-in is re-read out from the recording medium and error correction on the re-read-out signal in the vertical direction and the horizontal direction is effected by the use of the error correction code included in the signal. Data is thereby reproduced.
摘要:
An information recording and/or reproducing apparatus includes a head for effecting information recording on and/or information reproduction from a recording medium. The head is moved to a desired track on the recording medium by a driving device. A tracking error signal of the head, generated when the head is moved by the driving device is detected. At every predetermined period of the tracking error signal, the head drive velocity is calculated from a distance corresponding to the predetermined period and a time corresponding to the predetermined period. The calculated velocity is corrected on the basis of an acceleration of the head and a time period during which the acceleration is applied, so that the driving device is controlled by use of the corrected drive velocity.