Abstract: When a write processing portion in the disk driver receives a plurality of write requests from an application program, the write processing portion divides the data designated by the request into the data block unit, adds the control block including the reverse index showing a position on the original region on the disk apparatus where the data block is supposed to be originally written in the data block queue, and store the data in the log region secured separately from the original region on the disk apparatus. The rearrangement processing portion repeats an operation of rearranging the oldest effective data block to a position on the original region where the data block are supposed to be originally written. The recovery processing portion takes out the reverse index from the control block on the log region to recover the forward index.

Abstract: The invention discloses a novel ester compound of an unsaturated carboxylic acid represented by the general formula in which R1 is preferably a hydrogen atom or methyl group, R2 is preferably a trifluoromethyl group, R3 is a non-aromatic polycyclic hydrocarbon group or, preferably, an adamantyl group and R4 is preferably a hydrogen atom or methyl group. This unsaturated ester compound is polymerizable to give a (co)polymeric resin which can be used as a base resinous ingredient in a photoresist composition for light exposure with ultraviolet light of a very short wavelength by virtue of the high transparency to the short-wavelength light. A synthetic method for the preparation of the novel ester compound is disclosed.

Abstract: A cluster system managing a plurality of disk drives as a component of a virtual RAID comprises a cluster manager and a control unit. The cluster manager converts a global command G into local commands and a parity calculate command. The control unit comprises a command conversion function means, a disk control means, a parity calculation means, and a command transfer means. The command conversion function means makes the cluster manager convert the command G into the commands. The disk control means reads/writes from/to the units to according to the commands. The parity calculation means calculates the parity according to the command. The command transfer means transfers the command to one of the computer, the disk control means and the parity calculation means according to the commands.

Abstract: A distributed system of this invention forms multiplexing by n computers, and permits up to f computers to fail and halt. Respective computers exchange input candidates via an internal network B, and generate lists of input candidates. Each computer repeats generation of the list until (n−f) identical input candidates appear in that list. A computer which satisfies this condition executes its process irrespective of the states of other computers. This distributed system never generates a split brain in principle, and never interrupts a process upon occurrence of a failure due to time-out since it does not perform any failure detection.

Abstract: The invention discloses a novel ester compound of an unsaturated carboxylic acid represented by the general formula 1

Abstract: An HA (High Availability) scenario compiler is arranged in one of a group of computers constituting a multi-computer system, or a computer independent of the system. An HA scenerio abstractly and integrally describing the configuration and control contents of the system is read and decomposed into separate processes for the respective computers. An HA script set in a form directly executable by the respective computers is generated from the HA scenario. HA script for each one of the computers are respectively distributed to specific directories of the computers by an HA script distribution mechanism.

Abstract: A timeout monitoring system including plural timeout value setting mechanisms, each of which sets a timeout value as a result of the start-up. Also included is plural timeout monitoring mechanisms, each of which do not start the timeout value setting mechanism at the following stage but stop it, when the timeout value set by the timeout value setting mechanism at the preceding stage is not set again even after a specific time has elapsed. A watchdog timer outputs an abnormality notice, when the timeout value set by the timeout value setting mechanism at the last stage is not set again even after a specific time has elapsed. Hierarchizing the software of the watchdog timer makes it possible to set a suitable timeout value in the watchdog timer for a higher-speed sensing of timeout and monitor the timeouts of plural systems at plural levels, which improves the monitoring capability.