Abstract: A compact card type disk drive includes a housing (21) for accommodating a disk for storing data, a disk drive for rotating the disk, a head assembly for writing and reading data to and from the disk and an electronic circuit including at least an interface circuit (39), the latter three being accommodated in the housing. A connector (42) connected to the electronic circuit is fixed to the outside portion of the housing (21). The electronic circuit preferably contains a read/write circuit (36) and a control circuit (38). The housing (21) preferably includes a lower base (22) and an upper cover (23), and a printed circuit board (14) is disposed along the inner wall of either one, or both, of the base (22) and the cover (23). The outer dimension of the plane of the disk drive is preferably about 85.6 mm.times.54 mm, and typically, the outer thickness is 5 mm. Preferably, one connector (42) is disposed on either one of the minor sides of the housing (21).

Abstract: A compact card type disk a drive includes a housing (21) for accommodating a disk for storing data, a disk drive for rotating the disk, head assembly for writing and reading data to and from the disk and an electronic circuit including at least an interface circuit (39), the latter three being accommodated in the housing. A connector (42) connected to the electronic circuit is fixed to the outside portion of the housing (21). The electronic circuit preferably contains a read/write circuit (36) and a control circuit (38). The housing (21) preferably includes a lower base (22) and an upper cover (23), and a printed circuit board (14) is disposed along the inner wall of either one, or both, of the base (22) and the cover (23). The outer dimension of the plane of the disk drive is preferably about 85.6 mm.times.54 mm, and typically, the outer thickness is 5 mm. Preferably, one connector (42) is disposed on either one of the minor sides of the housing (21).

Abstract: A compact card type disk drive includes a housing (21) for accommodating a disk for storing data, disk drive for rotating the disk, a head assembly for writing and reading data to and from the disk and an electronic circuit including at least an interface circuit (39), the latter three being accommodated in the housing. A connector (42) connected to the electronic circuit is fixed to the outside portion of the housing (21). The electronic circuit preferably contains a read/write circuit (36) and a control circuit (38). The housing (21) preferably includes a lower base (22) and an upper cover (23), and a printed circuit board (14) is disposed along the inner wall of either one, or both, of the base (22) and the cover (23). The outer dimension of the plane of the disk drive is preferably about 85.6 mm.times.54 mm, and typically, the outer thickness is 5 mm. Preferably, one connector (42) is disposed on either one of the minor sides of the housing (21).

Abstract: A magnetic disc apparatus using an electric filter for waveform equalization of a read signal is provided. The optimum parameters are set for every head and the writing and reading operations are executed on the basis of the optimum characteristics. At the start of the use of the apparatus, the control information of the circuit parameters previously recorded on a magnetic recording medium is read out, thereby forming a set value table in which the optimum values of the circuit parameters including at least the electric filter have been stored every magnetic head. After the table was formed, prior to the writing or reading operation, the contents of the set value table corresponding to the designated magnetic head are read out and the circuit parameters of the circuit section including the electric filter are controlled and optimized on the basis of the contents read out.

Abstract: A retracting assembly produces a constant torque, in a data zone of a magnetic disk, which is greater than static friction of a bearing for a rotary actuator. However, in a parking zone on an outer portion of the magnetic disk, the retracting assembly generates a torque which suddenly increases so that a large holding torque is obtained and a magnetic head is reliably locked.

Abstract: A track access control system for a magnetic disc system including a magnetic disc having a plurality of servo tracks in a plurality of track zones divided in a radial direction, a logical to physical track address translation unit, a track offset update unit, and a control unit, to access a magnetic head at a physical track with offset correction. The track offset update may be carried out in an initial condition, or when a seek command is received. Also, the track offset update may be compulsorily effected when the update is not effected in a predetermined time. In this case, the system may output a virtual error data. In addition, the track offset update may be effected in response to a temperature change of the system.

Abstract: In writing (1-7) RLL coded write data into a magnetic disk, a write data fetching circuit wherein a clock signal of a frequency three times a fundamental frequency of a write clock signal is generated based on a signal from a servo head of the magnetic disk, three clock signals are generated from the clock signal, one of the three clock signals and the write clock signal are synchronized, and the write data output in accordance with the write clock signal is subjected to (1-7) RLL encoding using a clock signal synchronized with one of the three clock signals, whereby stable (1-7) RLL encoding is made possible without the use of a precise clock signal with a 50 percent duty ratio.

Abstract: An improved track access control system for a magnetic disk apparatus connectable to a variety of host controllers without any change thereto, and capable of an offset correction. A control unit in the disk apparatus controlling a moving unit to access a magnetic head at a desired track on the magnetic disk in response to a seek command from a host controller and using an offset correction value which is previously obtained by accessing the magnetic head at a track storing the fine positioning information, and carrying out an offset correction, includes a timer to which a time to be offset-updated within a predetermined timing is set.