International Business Machines Corporation

Richard Rolls

Stephen Peter Legg

George Anthony Dunn

Norman Apperley

James R Shipman

Brian Lee Morger

Teras Eve Yonker

Peter Allen Cummings

An adapter for converting an interface of a data storage device is provided. The adapter includes a first interface for connection to the interface of the data storage device and a second interface for connection to a plurality of host systems. The first interface may be an ATA or SCSI interface and the second interface may be a SSA or FC-AL interface suitable for attachment to multiple host systems. Conversion means are provided by the adapter for converting commands and data between the first and second interfaces. The adapter also has means for sorting commands and data to and from the plurality of host systems. The adapter acts as a single host system for the data storage device and includes means for retrieving error information from the data storage device in the event of a command terminating in an error. The adapter also comprises means for entering an error handling state with one of the plurality of host systems that persists until terminated by the host system and means for transferring the retrieved error information to the host system.

Adapter and method for handling errors in a data storage device converted to be accessible to multiple hosts

A method and means for performing logical-combining functions such as XOR operations in a RAID 3 or 5 array or a combinational configuration of disk drives. The logical combining occurs below the device attachment interface and is used in generating new parity for write update operations and data rebuilding. Each disk drive is modified to use a segmented and address synchronized buffer in the write and read paths, and a logical circuit that combines the data in the write path before buffering with the data in the read buffer as it is read out from the buffer. The logically combined result is presented at the device read path interface. The combined data from a first disk drive interface is introduced into the write path of a second path through the second device interface and the logical combining repeated ad seriatim, the device interfaces being connectable in a daisy-chain manner and configurable by array controller commands.

Method and means for managing disk drive level logic and buffer modified

A method and apparatus are provided for controlling communications on a small computer system interface (SCSI). A cache memory is arranged for storing an input queue, a status queue and a cache operation queue. An input engine detects unsolicited data from the SCSI and transfers the detected unsolicited data to the input queue. A status engine transfers status information between the SCSI and the status queue. A cache engine transfers data between the SCSI and the cache operation queue. Each of the input engine, the status engine, and the cache engine is independent to enable full duplex operation. A connection arbitrator is shared between the input engine, the status engine, and the cache engine enabling a connection to be shared by the input engine, the status engine, and the cache engine.

Method and apparatus for communications control on a small computer

Growing community of inventors

San Jose, CA, United States of America

Richard Rolls