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1. 发明专利

JPH0438675A MULTIPLXING FILING DEVICE 失效
公开(公告)号：JPH0438675A
公开(公告)日：1992-02-07
申请号：JP14245790
申请日：1990-05-31
申请人： HITACHI LTD , HITACHI COMPUTER PERIPHERALS
发明人： KOJIMA AKIRA , HIROSE TSUNEO , TAKEMOTO KIYOTAKA , YUGAWA YOSHIO , NISHIMURA KENJI , KUBO MITSURU , TAKAYASU ATSUSHI , NAKAMURA AKIHIRO , KANEKO MASAMI
IPC分类号： G06F3/06 , G11B19/02 , G11B19/28
摘要： PURPOSE:To surely shorten the time required for access by shifting rotation reference positions of respective rotating storage mediums of plural rotating storage devices from the others by an arbitrary extent at any time and synchronously rotating them in this state. CONSTITUTION:A magnetic disk device S has the rotation reference position (rotation reference position signals 19m and 19s) relatively shifted from rotation position information 20m obtained from a magnetic disk device M by a desired angle (1/2 rotation=180 deg. in this case) and is rotated synchronously with the magnetic disk device M. Consequently, a target sector where object data is stored is accessed within a maximum of 1/2 rotation (that is, an average waiting time is the time of 1/4 rotation) in either magnetic disk device. Thus, the time required for read processing of specific data is considerably shortened.

2. 发明专利

JPH02206076A POSITIONING SYSTEM FOR MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH02206076A
公开(公告)日：1990-08-15
申请号：JP2577489
申请日：1989-02-06
申请人： HITACHI LTD
发明人： TAKEMOTO KIYOTAKA , KONO SADAO , YUGAWA YOSHIO
IPC分类号： G11B21/08
摘要： PURPOSE:To contrive the improvement of the data transfer efficiency by constituting this system so that data extending over several cylinders can be transferred continuously without a moving time of a head and a rotation waiting time. CONSTITUTION:Two sets of data surface carriages 1a, 1b on a servo-surface exclusive carriage 1c are fixed in advance on the same cylinder as the servo- surface before seek is started, and positioned in the data track center by sector servo-information after arriving at a target cylinder. When a servo-head 4 is fixed to a specific cylinder of the servo-surface, two sets of carriages 1a, 1b can move separately within a range of several tracks, based on the sector servo-information. In this state, after data of a head of one carriage completes all read-out and write, each carriage 1a, 1b having several pieces of heads 2, 4 moves to the next cylinder, based on the sector servo-information and executes positioning in the course of read-out and write of the other carriage.

3. 发明专利

JPH01314325A MEMORY ACCESS SYSTEM FOR MAGNETIC DISK 失效
公开(公告)号：JPH01314325A
公开(公告)日：1989-12-19
申请号：JP14571088
申请日：1988-06-15
申请人： HITACHI LTD
发明人： TAKEMOTO KIYOTAKA , HIROSE TSUNEO , KOJIMA AKIRA
IPC分类号： G06F3/06 , G06F13/28 , G11B20/10
摘要： PURPOSE:To increase the data transfer speed of the magnetic disk device by using a conventional device by latching data read out of a magnetic disk and write data by two bytes, and synchronizing a DMA (direct memory access) data bus and determining the priority of data. CONSTITUTION:When a two-byte latch system is employed, 8-bit data read out of the magnetic disk is inputted from a line 32 and after the data of a 1st byte is latched, the data of a 2nd byte is latched; and the transfer of the data of the 1st byte only needs to be finished until the data of a 3rd byte is latched. A sequence circuit gives priority to data which can not be intermitted at a constant period, i.e. the read data from the magnetic disk device and write data and synchronizes the data bus with a reference clock. Consequently, the DMA data bus 17 is used efficiently to prevent data from overrunning.

4. 发明专利

JPH04289567A MAGNETIC HEAD POSITIONING MECHANISM FOR MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH04289567A
公开(公告)日：1992-10-14
申请号：JP7720591
申请日：1991-03-18
申请人： HITACHI LTD
发明人： SHIONO TOSHIO , TAKEMOTO KIYOTAKA
IPC分类号： G11B21/12 , G11B21/22
摘要： PURPOSE:To provide the head positioning mechanism in a small size and capable of a reliable head retracting operation by using a battery (especially a rechargeable battery) as a driving power source for retracting a head. CONSTITUTION:Under a normal positioning control, a carriage 1 having the head 2 is driven to be controlled by a driving current from a VCM circuit 20 to a voice coil 5, and at this time, the battery 21 is charged through on- contacts of switches 23a and 23b by a power source in a control circuit 22. When the device power source is turned off, a current for retracing the head is supplied to the coil 5 through off-contacts of the 23a and 23b by the battery 21 for a prescribed period of time (from the time when a disk is still rotating at high speed while the head is floating to the time when the disk is completely stopped and the head is brought into contact with the disk) set by a timer incorporated in the circuit 22, and hence the carriage is pressed against a stopper 6 by retracting force generated in this way.

5. 发明专利

JPH0612853A MAGNETIC DISK DEVICE 失效
公开(公告)号：JPH0612853A
公开(公告)日：1994-01-21
申请号：JP16723792
申请日：1992-06-25
申请人： HITACHI LTD
发明人： SHIONO TOSHIO , TAKEMOTO KIYOTAKA
IPC分类号： G11B5/455 , G11B23/42 , G11B33/10 , G11B33/12
摘要： PURPOSE:To provide a magnetic disk device capable of confirming the service life specification of 20,000 hours and 10,000 times CSS by counting the accumulated periods of time for power supply and the number of on and off times in addition to five years from a shipping day and making it possible to display them. CONSTITUTION:A circuit board 4 is provided with a RAM for recording and updating the accumulated hours of the power supply and the number of on and off times, a battery or a charging type battery 6 for maintaining the information of the RAM 5 when the power is off and a display section 7 for displaying the accumulated hours of the power supply and the number of on and off times. The accumulated hours when the power is supplied and the number of on and off times of the power supply are recorded both on a magnetic disk 1 and the RAM 5.

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