Fujitsu Corporation

Hiroaki Uno

Takashi Onodera

Noriyuki Yokoshi

Takumi Maruyama

Kenichi Kuwako

Nobuko Hatakenaka

Yasutsugu Nagusa

Hideaki Miyashita

A secondary storage device using a nonvolatile semiconductor memory in which individual block areas constituting the nonvolatile semiconductor memory can be used up to their limit of use. When the number of repetitions of erasure in a second block area has reached a predetermined reference value, a searching unit searches active block areas for an alternate block area. A second writing unit writes information which has been stored in the alternate block area, into the second block area. A second correspondence modifying unit associates the physical block number with the logical block number and causes a logical-physical correspondence storing unit to store the correspondence of the thus-associated block numbers. A second erasing unit erases the information stored in the alternate block area and treats the block area with the physical block number as a spare block area.

Secondary storage device using nonvolatile semiconductor memory

An apparatus for controlling synchronization in a system having at least first and second units each having internal circuits includes signal paths through which a control signal output from a second unit is sent to a first unit and a control signal output from the first unit is sent to the second unit. A first preparatory process part carries out a process to place the internal circuits of the second unit in an operating state when the second unit is connected to the system and for outputting a control signal to the signal paths. A first function mask control part is provided for stopping the operation of the internal circuits of the second unit when a control signal from the first unit is not received by the second unit, and for restarting the operation of the internal circuits when the control signal is received. A second preparatory process part carries out a process to place the internal circuits of the first unit in an operating state when the control signal from the second unit is received by the first unit, and for outputting a control signal to the signal paths. A second function mask control part is provided for stopping the operation of the internal circuits of the first unit when the control signal is not received, and for re-starting the operation of the internal circuits when the control signal is received.

Controlling synchronization in a system having a plurality of units when

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Osaka, Japan

Hiroaki Uno