International Business Machines Corporation

Daniel Eugene Pridgeon

Scott Leonard Daniels

Norman Karl James

Thomas R Forrer, Jr

James Douglas Jordan

Pat Allen Buckland

A method and an apparatus is presented for configuring a system bus topology dynamically. In a preferred embodiment, the system bus is a Small Computer System Interface (SCSI) bus that connects a 'daisy' chain of disk drives. Two types of disk drives are used: single ended (SE) 'Ultra' drives capable of 20 MHz operation and LVD (low voltage differential) &#x201c;Ultra Plus&#x201d; drives capable of 40 MHz operation. LVD disk drives can also function in the slower SE mode. The first drive in the chain of drives may need to be connected by a cable over three feet long. This introduces signal degradation that is often overcome by introducing redrive circuitry to boost signal quality. This is an expensive solution and a much easier solution is presented: install a jumper between the last drive in the chain and the first drive. However, if LVD bus mode is used, then this jumper solution does not work and the jumper must be removed. Disk drives in a server system are &#x201c;hot swappable,&#x201d; which means they can be changed at run time without shutting down the system. A method and an apparatus is provided for dynamically testing for the appropriate mode of bus operation based on the currently installed disk drives and adjusting the jumper setting accordingly.

Method and an apparatus for dynamically reconfiguring a system bus topology

A power-supply filter that is built into an integrated circuit package is disclosed. An LC, RC, or RLC filter is built into the integrated circuit's chip carrier module and connected so as to filter the power supply entering the integrated circuit. By manufacturing the filter as part of the integrated circuit package, a chip manufacturer can eliminate the need for application-level developers to provide an external filtering network in the deployment of the integrated circuit in an application circuit.

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Austin, TX, United States of America

Daniel Eugene Pridgeon