US 6,154,791 A · Communication system for an array of direct access storage devices (DASD) that provides for bypassing one or multiple DASD

Abstract

A communication system for an array of DASD includes a plurality of loop resiliency circuits and a plurality of selection circuits. The DASD array includes a plurality of DASD slots. Each DASD slot may receive a DASD, and each DASD receives power from a regulator. The loop resiliency circuits form at least a first communication path. Each loop resiliency circuit is associated with one of the DASD slots and selectively includes the associated DASD slot in the first communication path based on a selection signal. The plurality of selection circuits are also associated with one of the DASD slots; and therefore, are also associated with one of the plurality of loop resiliency circuits. Each selection circuit is connected to the associated DASD slot and receives output from the regulator in the associated DASD slot. Based on the regulator output, or a lack thereof, the selection circuit generates a selection signal for the associated loop resiliency circuit. Besides being serially connected to form a single communication path, the loop resiliency circuits can be divided into groups wherein the loop resiliency circuits in each group are serially connected to form a communication path. Separate loop resiliency circuits then selectively connect these communication paths to a main communication path including an initiator. As a further alternative, a second initiator can be selectively placed in one of the communication paths via another loop resiliency circuit.

Claims17

Dependent claims

A communication or DASD system for an array of direct access storage devices or DASD, the array including a plurality of DASD slots, each DASD slot for receiving a DASD and each DASD receiving power from an associated regulator, the system comprising:

a plurality of loop resiliency circuits forming at least a first communication path, each loop resiliency circuit associated with one of the DASD slots and selectively including the associated DASD slot in the first communication path based on a selection signal;
a plurality of local selection circuits, each selection circuit associated with one of the DASD slots and one of the plurality of loop resiliency circuits, each selection circuit connected to the associated DASD slot to receive output of a regulator if the associated DASD is in the associated DASD slot, and each selection circuit generating, without receipt of an external control signal, the selection signal based on one of the output from the regulator and a lack thereof, the output of the regulator indicating whether power is being supplied to the associated DASD.

Dependencies are inferred from the claim text.

Communication system for an array of direct access storage devices (DASD) that provides for bypassing one or multiple DASD

Life of this patent

Communication system for an array of direct access storage devices (DASD) that provides for bypassing one or multiple DASD

Life of this patent

Abstract

Claims17