International Business Machines Corporation

Hiroyuki Iwasa

Hideo Asano

Masayuki Murakami

Hirofumi Saitoh

Yutaka Shimizu

Hiroaki Okumiya

Akira Takeshita

Makoto Tsurumi

A redundant disk storage system having data stored on one disk and identical data on second disk, wherein the data stored on the second disk is in a different radial location determined by an offset. The offset could be such that the data on the first disk is stored near the inner circumference and the identical data is stored on the second disk near the outer circumference. Moreover, a RAM associated with each disk drive which stores the address and offset eliminates a RAM in the main disk controller.

Method and apparatus for redundant disk storage system with offset

An adapter connected between a host computer and disk storage devices provides interfaces for connecting to the host computer and the disk storage devices having the same interface design. The adapter itself includes control means for building a redundant disk storage system. Moreover, the adapter itself includes means for detecting and indicating a failed disk storage device, means for replacing the failed disk storage device, and means for rebuilding a redundant disk storage system after the replacement of disk storage devices. A command is configured so that the host computer can have access to each of disk storage devices for maintenance purposes. The adapter makes it easy to configure a highly reliable redundant disk storage system for a small computer system without any change to existing hardware or software.

Adapter for constructing a redundant disk storage system

In a computer system including a host which operates in a pre-read mode to start a block data transfer after reading status of a peripheral device (HDD) in response to an interrupt from the peripheral device or in a post-read mode to read the status after completing the block data transfer, an interface circuit comprising mode detecting circuitry for automatically detecting whether the host operates in the pre-read mode or in the post-read mode so that data transfers can be correctly performed between the peripheral device and the host even if the host is in either mode, delay circuitry for delaying by a predetermined amount of time, a data request DRQ indicating that a block of data is ready to be transferred, when the post-read mode is detected, and interrupt circuitry for sending an interrupt request IRQ to the host in response to the output of the delay circuitry.

Interface circuit for controlling data transfers

Growing community of inventors

Fujisawa, Japan

Hiroyuki Iwasa