Abstract: A disk drive is disclosed which performs a head positioning operation capable of coping with a variation of an offset caused by a disk runout. A CPU of a head positioning control system calculates a second position offset amount by correcting a first position offset amount corresponding to a rotation angle of an actuator on a disk medium based on a disk runout amount. The CPU performs head positioning control including a position correction operation corresponding to a second position offset amount.

Abstract: A magnetic recording medium includes a data area in which data can be written and a servo area in which information is recorded for positioning a magnetic head to a target position. The servo area has a preamble area for clock synchronization and an address area where address information of sectors and cylinders is recorded, and a ratio of a magnetic portion to a non-magnetic portion in a total of the data area, the preamble area, and the address area is substantially 2:1.

Abstract: A semiconductor memory device formed on a semiconductor chip comprises a plurality of first memory arrays, a plurality of second memory arrays, a first voltage generator, and a plurality of first bonding pads. The semiconductor chip is divided into a first rectangle region, a second rectangle region, and a third rectangle region and the third rectangle region is arranged between the first rectangle region and the second rectangle region. The plurality of first memory arrays are formed in the first rectangle region. The plurality of second memory arrays are formed in the second rectangle region. The voltage generator and the plurality of first bonding pads are arranged in the third rectangle region. The plurality of first bonding pads are arranged between the first rectangle region and the voltage generator and no bonding pads are arranged between the voltage generator and the plurality of second memory arrays.

Abstract: A perpendicular magnetic recording type of disk drive having function of removing a component of a shift in a base line of a reproducing signal is to be disclosed. The disk drive has a read channel including an extracting unit which extracts the component of the shift in the base line of the reproducing signal. The extracting unit includes low-pass filters, and parameters of a lower cut-off frequency of the low-pass filter are adjusted in read operation.

Abstract: A disk drive of a perpendicular magnetic recording system has a magnetization test function, for testing the magnetized state of a write head. The disk drive is provided with a write driver and a head amplifier unit. The write driver supplies a write current to the write head, for perpendicular magnetic recording. The degaussing unit degausses the write head.

Abstract: In a disk drive of the perpendicular magnetic recording method, there is disclosed a servo data encoding method for recording servo data with a particularly low frequency on a disk. The coded data of the servo data by this method is coded with DC free code which is capable of suppressing a direct current component of the read signal waveform. As a consequence, in the case where signal processing is conducted in the read/write channel by the cut-off low frequency characteristic, a waveform distortion can be suppressed which is generated in the read signal waveform by the cut-off low frequency characteristic. Consequently, an improvement in the read error rate in the read/write channel can be realized.

Abstract: There is disclosed a disk drive which can appropriately execute a gain control of an AGC amplifier included in a read channel for each zone on a disk. A CPU refers to table information stored in a memory, and reads initial gain data corresponding to the zone during switching of the zone as a read object. The CPU sets the read initial gain data into the AGC amplifier.

Abstract: A disk drive which includes a head amplifier having a function of degaussing a magnetic head effective to suppression of an EAW phenomenon is disclosed. The head amplifier includes a degaussing controller which performs switching from write operation to degaussing operation, a write driver which outputs degaussing current necessary for the degaussing operation, and a current control unit which sets a current waveform of the degaussing current.

Abstract: A semiconductor memory device formed on a semiconductor chip comprises a plurality of first memory arrays, a plurality of second memory arrays, a first voltage generator, and a plurality of first bonding pads. The semiconductor chip is divided into a first rectangle region, a second rectangle region, and a third rectangle region and the third rectangle region is arranged between the first rectangle region and the second rectangle region. The plurality of first memory arrays are formed in the first rectangle region. The plurality of second memory arrays are formed in the second rectangle region. The voltage generator and the plurality of first bonding pads are arranged in the third rectangle region. The plurality of first bonding pads are arranged between the first rectangle region and the voltage generator and no bonding pads are arranged between the voltage generator and the plurality of second memory arrays.

Abstract: A disk drive is disclosed which performs a head positioning operation capable of coping with a variation of an offset caused by a disk runout. A CPU of a head positioning control system calculates a second position offset amount by correcting a first position offset amount corresponding to a rotation angle of an actuator on a disk medium based on a disk runout amount. The CPU performs head positioning control including a position correction operation corresponding to a second position offset amount.

Abstract: A semiconductor memory device, in which peripheral circuits are arranged in a cross area of a semiconductor chip composed of the longitudinal center portions and the transverse center portions, and in which memory arrays are arranged in the four regions which are divided by the cross area. This structure in which the peripheral circuits are arranged at the center portion of the chip permits the longest signal transition paths to be shortened to about one half of the chip size to speed up the DRAM which is intended to have a large storage capacity.

Abstract: A divider 3 for dividing and distributing a high-frequency signal input from an input terminal 1 to two output sides, a main amplifying unit 4, connected to one output side of the divider 3, for amplifying one high-frequency signal output from the divider 3, a subsidiary amplifying unit 5, connected to the other output side of the divider 3, for performing no operation in case of a low instantaneous electric power of the other high-frequency signal output from the divider 3 and amplifying the other high-frequency signal in case of a high instantaneous electric power of the other high-frequency signal and a circulator 6 for injecting the high-frequency signal amplified in the subsidiary amplifying unit 5 into the output side of the main amplifying unit 4 and injecting the high-frequency signal amplified in the main amplifying unit 4 into an output terminal 2 are arranged.

Abstract: In a disk drive that performs perpendicular magnetic recording, the read/write channel has a sync mark generator. The sync mark generator generates a second sync mark before the read/write channel operates to write data on a disk. The second sync mark has a bit pattern including a series of bits representing positive polarity and a series of bits representing negative polarity. The series of bits, which is longer than the other, has a bit length that is at least 50% but less than 85% of the total bit length of the second sync mark.

Abstract: Herein disclosed is a semiconductor memory device, in which peripheral circuits are arranged in a cross area of a semiconductor chip composed of the longitudinal center portions and the transverse center portions, and in which memory arrays are arranged in the four regions which are divided by the cross area. Thanks to this structure in which the peripheral circuits are arranged at the center portion of the chip, the longest signal transmission paths can be shortened to about one half of the chip size to speed up the DRAM which is intended to have a large storage capacity.

Abstract: A perpendicular magnetic recording type of disk drive having function of removing a component of a shift in a base line of a reproducing signal is to be disclosed. The disk drive has a read channel including an extracting unit which extracts the component of the shift in the base line of the reproducing signal. The extracting unit includes low-pass filters, and parameters of a lower cut-off frequency of the low-pass filter are adjusted in read operation.

Abstract: A partial response (PR) waveform generator generates a digital value sequence of an expected PR waveform based on the output of a soft-decision Viterbi detector included in, for example, a first-stage decoder unit incorporated in an iterative decoder. The generator also generates flag information indicative of whether reliability of the digital value sequence is low or high, in parallel with the generation of the digital value sequence. An error detector detects error values in a PR equalized sample value sequence, needed for feedback control of a control target, using the digital value sequence of the expected PR waveform as a digital value sequence of a reference waveform. An error output controller controls the output of the error values detected by the error detector in accordance with the state of the flag information generated by the generator.

Abstract: A semiconductor memory device, in which peripheral circuits are arranged in a cross area of a semiconductor chip composed of the longitudinal center portions and the transverse center portions, and in which memory arrays are arranged in the four regions which are divided by the cross area. A benefit of this structure in which the peripheral circuits are arranged at the center portion of the chip, is that the longest signal transmission paths can be shortened to about one half of the chip size to speed up the DRAM which is intended to have a large storage capacity.

Abstract: A supplying method and a supplying apparatus for supplying fluorine gas, in which when a fluorine-occluding substance is used for the fluorine gas-generating means, a necessary amount of fluorine gas can be stably and swiftly supplied to have a uniform concentration to &a chamber of an excimer laser device or the like even at running, to say nothing of the gas exchange time. In a fluorine gas-generating means, fluorine gas is generated at the use point by controlling a fluorine-occluding substance to a predetermined temperature, the fluorine gas is introduced into a mixing container, a diluting gas is introduced into the mixing container to mix it with the fluorine gas to prepare a fluorine mixed gas having a predetermined pressure and a predetermined fluorine gas concentration, and the fluorine mixed gas reserved in the mixing container is supplied to a use side such as chamber, using the pressure difference.

Abstract: A feedforward amplifier combines an input signal combined by a first error rejection loop with an error component and a first pilot signal detected by a second error detection loop, thereby canceling out the error component and the first pilot signal residual in the input signal.

Abstract: Herein disclosed is a semiconductor memory device, in which peripheral circuits are arranged in a cross area of a semiconductor chip composed of the longitudinal center portions and the transverse center portions, and in which memory arrays are arranged in the four regions which are divided by the cross area. Thanks to this structure in which the peripheral circuits are arranged at the center portion of the chip, the longest signal transmission paths can be shortened to about one half of the chip size to speed up the DRAM which is intended to have a large storage capacity.