International Business Machines Corporation

Matsushita Electric Industrial Co., Ltd.

James Richard Pollock

Gregg Steven Lucas

Adalberto Guillermo Yanes

Enrique Q Garcia

James C Chen

Juan Antonio Yanes

David C Giese

The error offset and the error magnitude of a data stream in a Read-Solomon code is calculated using the same architecture. The advantage this method has over previous techniques is its simplicity of design and the minimum steps required to convert the syndrome information into an error location and correction pattern. The maximum of four cycles (steps) needed to compute the offset and correction pattern allows for a correction to be applied in the byte time immediately following receipt of the last check byte.

Single error Reed-Solomon decoder

System and method aspects for avoiding data corruption during data transfer in a disk array environment are described. In a circuit aspect, an integrity checker includes counting logic for counting fields in the data being transferred. The integrity checker further includes comparison logic for comparing a constant value and a value in a predetermined field of data being transferred. Combinational logic is further included and coupled to the comparison logic and counting logic, wherein when the comparison logic results in a miscompare and the counting logic is at a predetermined count value, the integrity checker circuit aborts data transfer. In a method aspect, the method includes providing an integrity checker at an interface to an array of disk drives, and performing data validity determinations on data passing across the interface with the integrity checker, wherein invalid data is not transferred.

Method and circuit for data integrity verification during DASD data

A device controller is described within a data storage system for pre-fetching device work information from multiple data storage devices, and accumulating the device work information to immediately respond to a subsequent device poll command from a storage controller. The device controller includes a device receiver to receive the device poll command, a device transmitter to transmit a response to the device poll command, a device information register for storing the pre-fetched device work information for each data storage device, and a sequencer for periodically pre-fetching the device work information from each data storage device. The sequencer pre-fetches such information by verifying that no device subsystem command from the storage controller is pending in the device receiver, then issuing a background poll command to a selected device to query the device for its device work information, and storing the device work information in the device information register. The device controller can then immediately respond to a subsequent device poll command issued from the storage controller by copying the device work information from the device information register to the device transmitter.

Prefetching and storing device work information from multiple data

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San Jose, CA, United States of America

James Richard Pollock