Kabushiki Kaisha Toshiba

Masaharu Nozaki

Hideaki Hirayama

Tomofumi Shimada

Masao Ochiai

A method for recovering from software fault in a fault tolerant computing system includes a system status recording step to record the system status at the occurrence of the above software fault when the above fault is judged to be a software fault by a fault identifying step, a software fault factor diagnosing step to diagnose the fault factor of the above software fault, a software fault recovery action determining step to determine a recovery action to the above fault factor of the above software fault, and a software fault recovery action executing step to execute the recovery action the above fault factor of the above software fault determined by the above software fault recovery action determining step after roll back.

Method and apparatus for recovering from software faults

A data management system, which is equipped with a data file and a journal file and adapted to reserve the exclusive occupation for data and then update the data, is characterized by releasing the exclusive occupation of data prior to writing of a journal to the journal file and of corresponding updated data to the data file. When data on a data base is updated, the exclusive occupation states of data to be updated are reserved first and then updating of the data is executed on a data buffer placed on a main memory and journals on the updating of the data are collected. The collected journals are entered into a first-in first-out journal queue in units of transactions. The exclusive occupation states of data on a corresponding transaction is released after corresponding journals have been stored in the journal queue. The journals stored in the journal queue are written to the journal file in units of transactions in the order in which they are entered into the queue. Subsequently updated data is written to the data file. The data in the data file is restored using the journal file when a system failure occurs in the data base.

Method and apparatus for reducing data locking time by removing a lock

A system of the invention has a compiler for converting a conditional branch instruction, located in a source program being converted into an object program, into a conditional branch instruction having a flag field in which data is set representing whether a branch has been made. A load module generated from the object program through a linker is stored in a main memory. An instruction fetched from the main memory is decoded by an instruction decoder. A branch condition determination section determines if the instruction is 'branch' or 'through' and changes the flag field data. The program, now including a conditional branch instruction with the changed data, is rewritten into the load module.

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Tokyo, Japan

Masaharu Nozaki