Electrical computers and digital data processing systems: input/ – Intrasystem connection – Bus access regulation
Reexamination Certificate
1998-12-15
2001-09-04
Beausoleil, Robert (Department: 2181)
Electrical computers and digital data processing systems: input/
Intrasystem connection
Bus access regulation
C710S108000, C235S492000
Reexamination Certificate
active
06286066
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to computers. More specifically, the invention relates to a switch device in a computer and an associated method of operation for notifying an hot-plug interface of insertion and removal of an adapter card.
2. Description of the Related Art
Computer systems communicate with various peripheral devices and other computer systems via communication buses. The peripheral devices are generally connected to the communication buses by an adapter card. Communication buses are generally fault-intolerant so that a failure of an adapter card may have a wide range of effects on system performance. In some cases, adapter card failure may prevent subsequent bus transactions. Some failures may corrupt main memory. Sometimes failure may result in the loss of only a single, localized network connection. Often, the effects are unpredictable.
A common cause of system failure is the accidental accessing, by removing or installing, adapter cards from a card slot connected to a communication bus while the card slot is powered and running. Although system manufacturers, systems administrators, and others warn of the dire consequences of adapter card manipulation while the card slot is powered, occasionally a card is accidentally removed or added while the slot is powered, typically resulting in failure of the server and loss of productive work by staff.
To prevent system failure due to card removal or addition while a slot is powered, a “Hot-Plug” specification has been adopted which sets forth devices and structures to allow insertion and removal of adapter cards from a powered communication bus. One such specification is a PCI (Peripheral Communication Interface) Hot-Plug specification which sets standards for aspects of removal and insertion of PCI adapter cards while the system is running. The Hot-Plug specification is applicable to desktop computers, portable systems, target server platforms, and the like.
Operating systems that are widely used in the computing industry are not generally designed to tolerate unexpected removal of devices. The Hot-Plug specification has thus been created to define a sequence of user actions and system management facilities that inform the operating system of a desire to remove an adapter card. The actual removal is not to occur until the software system acknowledges readiness.
In addition, adapter cards are not generally designed to be connected to a slot that is already powered. Accordingly, the Hot-Plug specification defines a sequence of user actions and system behavior to ensure the removal of power to a slot before a card is inserted into the slot.
The insertion or removal of an adapter card without following the proper sequence may cause unpredictable results, including data corruption, abnormal termination of the operating system, damage to the adapter card, or damage to platform hardware.
What is needed is an interface device and associated operating method that simply, conveniently, and inexpensively ensure that power is removed from a slot during removal and insertion of an adapter card.
SUMMARY OF THE INVENTION
Adapter cards generally have a metal bracket at one end. The adapter card attaches to an adapter card slot of a computer system by fastening the bracket to a connector on the computer system. Conventionally, the bracket is fastened to the connector using a screw. It has been discovered that an electrically-conductive flip-down retainer advantageously functions as an improved fastener to secure the adapter card to the connector. The electrically-conductive flip-down retainer is a single structure that performs the combined functions of an electrical switch and a mechanical fastener. The electrically-conductive flip-down retainer includes electrical contacts that form a closed circuit when the bracket is fastened to the connector and an open circuit when the bracket is not fastened. The electrical contacts are connected to conductors extending to a controller. The controller monitors the status of the electrical switch of the electrically-conductive flip-down retainer and controls application of power to the adapter card slot, typically under control of an operating system. The controller terminates power to the adapter card slot when the electrically-conductive flip-down retainer is unfastened, indicating that the adapter card is disengaged from the adapter card slot. The controller restores power to the adapter card slot when the electrically-conductive flip-down retainer is fastened, indicating the adapter card is engaged with the adapter card slot.
The dual-functionality of the electrically-conductive flip-down retainer advantageously eliminates the need for a separate button or interactive user input to notify the operating system whether operating power is to be terminated or restored to an adapter card slot, and for which adapter card slot power is to be modified. The dual-functionality electrically-conductive flip-down retainer advantageously eliminates the risk of removal or insertion of the adapter card to an adapter card slot that has applied power.
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“PCI Bus Hot Plug Specification”, Revision 1.0, Jun. 15, 1997, pp. i-vi, and 1-29.
Hayes Stuart
Khatri Mukund P.
Beausoleil Robert
Dell U.S.A. L.P.
Koestner Ken J.
Phan Raymond N
Skjerven Morrill & MacPherson LLP
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