International Business Machines Corporation

John M Sheplock

Phillip G Williams

Timothy Carl Bronson

James A O'Connor

Justin Potok Bandholz

Glenn David Gilda

Martin Joseph Crippen

James Edward Hughes

Jeffery Michael Franke

Joseph Edward Bolan

David John Jensen

John K Langgood

Stefan P Jackowski

Jerry Don Ackaret

Wilson Earl Smith

Bay Van Nguyen

Derek Robertson

Brian E Bigelow

Kevin M Cash

Christopher Lee Durham

David L Cowell

A method and circuit for implementing an enhanced availability personality card for a chassis computer system, and a design structure on which the subject circuit resides are provided. The personality card includes a first erasable programmable read only memory (EPROM) and a second EPROM, each EPROM storing Vital Product Data (VPD) and a first temperature sensor and a second temperature sensor sensing temperature. A primary bidirectional bus and a redundant bidirectional bus are respectively connected between the first EPROM and the first temperature sensor and the second EPROM and the second temperature sensor, and a pair of chassis management modules. Each chassis management module includes a switch connected to both the primary bidirectional bus and the redundant bidirectional bus providing redundant paths, enabling continued function with failure of any critical personality card component.

Implementing ultra high availability personality card

Private devices are implemented on the secondary interface of PCI bridge by re-routing the activation of device select signals (IDSEL) during the address phase of a Type 0 configuration operation on the secondary bus in response to a Type 1 configuration operation on its primary bus. Under control of a mask register and device select reroute circuit, if a configuration command on the primary interface attempts to activate the IDSEL line associated with one of the private, or reroute, devices on the secondary interface, a different IDSEL is activated to select a monitoring device on the secondary interface.

System and method for implementing private devices on a secondary peripheral component interface

To prevent data performance impacts when dealing with target devices that can only transfer data for a limited number of bytes before disconnecting, the invention implements a short term data cache on the bridge. Using this feature, the bridge will cache additional data beyond a predetermined quantity of data following a disconnect with the requesting device. As such, the bridge may continue to prefetch additional data up to an amount specified by a prefetch read byte count and return the additional data should the requesting device request additional data resuming at the point of disconnect. However, the bridge will discard the additional data when at least one of the following occurs: a) the requesting device disconnects data transfer, and b) a further READ request that resumes at the point of disconnect is not received within a predetermined time.

Data caching on bridge following disconnect

An opaque memory region for a bridge of an I/O adapter. The opaque memory region is inaccessible to memory transactions which traverse the bridge either from a primary bus to secondary bus or secondary bus to primary bus. As a result, memory transactions which target the opaque memory region are ignored by the bridge, allowing for the same address to exist on both sides of the bridge with different data stored in each. The implementation of the opaque memory region provides a means to complete memory transactions within I/O adapter subsystem memory, hence, relieving host computer system memory resources. In addition, a number of I/O adapters can be used in a host computer system where the host and all the I/O devices use some of the same memory addresses.

Opaque memory region for I/O adapter transparent bridge

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Raleigh, NC, United States of America

John M Sheplock