Abstract: The invention relates to a magnetic recording device which can be used at a reduced atmospheric pressure without having the head/slider assembly stick to the disk. A method of the present invention for controlling the operation of a disk drive device in reduced atmospheric pressure where a read/write head mounted on a head support arm flies above the surface of a rotating recording disk. The head support arm is moved along a radial direction of the recording disk to position the read/write head to one of cylinder positions of the recording disk.

Abstract: The present invention is an apparatus and method to reliably unload a head slider from a recording medium. Transistor Tr5 is on. If the main power supply Vdd is turned off at time t1, Tr1, Tr2, and D1 are turned off and the level of the control signal Ret becomes higher than the threshold voltage Vth of Tr3 and Tr4, turning on Tr3 and Tr4. C1 also starts to discharge. The control signal InRet changes to a "L"-level, and the control signal OutRet remains to be at the "L"-level. This allows the IR driver to feed a negative-polarity VCM current through the voice coil to preliminarily move the head arm in the direction opposite to the unload direction. Then, at time t2 when the level of Ret becomes equal to or lower than Vth, both InRet and OutRet change to a "H"-level, the IR driver becomes inoperative, and the OR driver feeds a positive-polarity VCM current through the voice coil to reverse the moving direction of the head arm.

Abstract: The invention relates to a head mechanism control apparatus for magnetic recording device which ensures that the transducer head has been unloaded in a head unloading operation. A head slider having a transducer head is mounted on a head arm and is unloaded from the disk by the swinging of the head arm. The retract position is at the limit portion of the swingable range of the head arm. When the head slider is successfully unloaded to the retract position, a drive force applied to the head arm in the unload direction causes little movement of the head arm. After an unloading is performed, a position check drive force is applied to the head arm and the moving speed of the head slider is detected. Based on the moving speed, it is judged whether the head slider has been unloaded to the retract position. If the head slider has not been unloaded to the retract position, re-unloading is performed for moving the head slider to the retract position.

Abstract: A disk drive has an error recovery procedure with a plurality of ERP steps. An unused capacity of an alternate area on a disk for reassigning data is determined. While executing the error recovery procedure, an execution condition for reassigning data is changed based unused capacity of the alternate area. Data is reassigned to the alternate area in response to the execution condition. This prevents the early loss of the alternate area.

Abstract: A method of producing a grain-oriented electrical steel sheet with a very low core loss comprises the steps of obtaining a rolled strip of final product thickness using as a starting material molten steel consisting of not more than 0.10 wt % C, 2.5-7.0 wt % Si, ordinary inhibitor components and the balance of iron and unavoidable impurities, heating the strip to a temperature range of not less than 700.degree. C. at a heating rate of not less than 80.degree. C./s and within 0.1 second after the maximum temperature has been reached cooling the strip at a cooling rate of not less than 50.degree. C./s, and subjecting the strip to decarburization annealing and final finish annealing.

Abstract: A method of generating oxygen for emergency use wherein oxygen is generated by adding a catalyst such as manganese dioxide etc. to an aqueous solution prepared by intermixing an addition compound of sodium carbonate and hydrogen peroxide with water and wherein the catalyst is formed into a continuous and integral shape so as to thereby make it possible to put the catalyst into and take it out of the aqueous solution so that generation of oxygen can be started and stopped easily.

Abstract: A stripping column for removing volatile matter from a slurry containing sedimentary solid matter and the volatile matter, comprising a plurality of trays each consisting of a plurality of tray segments, a baffle plate and a downcomer, each of the tray segments being so formed as to have many inclined slits and inclined flat planes. In one embodiment, this invention relates to a process for such removal using the stripping column.