Abstract: A magnetic disk controller incorporating a cache memory which employs an LRU (Least Recently Used) scheme in a replacement algorithm of cache blocks and comprising a directory memory whose entries have LRU counter fields, a host system issuing a read/write command to which an arbitrary LRU settling value is appended, a directory search circuit, and a microprocessor. The directory search circuit searches the directory memory in response to the read/write command issued from the host system. The microprocessor stores the LRU setting value appended to the read/write command in the LRU counter field of the hit entry of the directory memory or of the entry corresponding to the repalacement target cache block, in response to the search result of the directory search circuit.

Abstract: A magnetic recording/reproduction apparatus of the invention has a magnetic head for reading a vertical magnetically recorded signal, an inplane magnetic recorded signal or a magnetic recorded signal having both a vertical magnetic component and an inplane magnetic component and for supplying a reproduced signal, a first analog signal converting circuit for converting the reproduced signal into an analog inplane reproduced signal when the reproduced signal is a vertical reproduced analog signal, a second analog signal converting circuit for bypassing an inplane analog reproduced signal when the reproduced signal is the inplane reproduced analog signal, and a third analog signal converting circuit for converting the reproduced signal into an inplane reproduced analog signal when the reproduced signal is the inplane reproduced analog signal. The circuits are switched to operate selectively in accordance with the type of signals reproduced from a magnetic recording medium.

Abstract: A cache system employing an LRU (Least Recently Used) scheme in a replacement algorithm of cache blocks and comprising a directory memory whose entires have LRU counter fields, a host system issuing a read/write command to which an arbitrary LRU setting value is appended, a directory search circuit, and a microprocessor. The directory search circuit searches the directory memory in response to the read/write command issued from the host system. The microprocessor stores the LRU setting value appended to the read/write command in the LRU counter field of the hit entry of the directory memory or of the entry corresponding to the replacement target cache block, in response to the search result of the directory search circuit.

Abstract: An impact printer which can be equipped with an auto sheet feeder comprises printing means, driving means for driving the printing means and controlling means for controlling the driving means so as to reduce the printing strength of the printing means when equipped with the auto sheet feeder. The impact printer makes it possible to reduce impact noises even when equipped with the auto sheet feeder, without lowering the quality of the characters, etc. printed.

Abstract: A floppy disc chucking device is provided for a floppy disc apparatus. The device comprises a permanent magnet for magnetically attracting a metallic chucking plate at the central portion of a floppy disc and a hub having a coupling surface closely in contact with the attracted chucking plate and rotated by a drive mechanism. The coupling surface of the hub is processed to form a coupling layer that has a predetermined thickness and a predetermined high hardness and provides a low coefficient of friction with the chucking plate in contact therewith.