Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A computer arrangement for facilitating the sharing of information among computers at a memory level. Each computer includes means for accessing the main memory of another computer of the complex at machine word level, means for transmitting an interruption instruction from itself to the arithmetic control unit of the other computer, means for detecting a problem in the arithmetic control unit of itself, and means for altering one section of the logic address viewed from itself to some of a plurality of physical address spaces such as to make the same the logic address of a shared information storage region of the computer complex viewed from the program of each of the member computers. Shared information required for each computer is stored in its own main memory. When a problem occurs in the computer having the aforesaid shared information storage region it becomes evident in the computer's arithmetic control unit. As a result, an interruption instruction is sent to each of the other computers.