National Semiconductor Corporation

Jeffrey A Hawkey

Kenneth C Ma

Pranay D Shah

Kenneth J Kotlowski

A secondary bus controller allows for hot insertion and ejection of devices from the secondary bus without ceasing operations or halting software in the host computer. When a device is to be inserted a signal is sent to the secondary bus controller. The secondary bus controller suspends operation of the secondary bus, placing devices on the secondary bus in stasis. An interrupt handler reconfigures the system for the newly inserted card once it has been inserted. Attempts to access devices on the secondary bus during the insertion process may be met with a retry signal until insertion is complete. The ejection process follows similar steps, isolating and suspending operations on the secondary bus and triggering an interrupt routine in the host processor to reconfigure the system. The host processor and primary busses, along with the secondary bus controller remain active throughout the insertion or ejection processes. Thus, applications running on the host computer need not be terminated during insertion or ejection. The present invention has particular application to network server computer systems.

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Morgan Hill, CA, United States of America

Jeffrey A Hawkey