Concurrent maintenance for PCI based DASD subsystem with concurrent maintenance message being communicated between SPCN (system power control network) and I/O adapter using PCI bridge
First Claim
1. In an electrical system having a system power controller and at least one system component coupled to the electrical system by a first communications path having a input/output adapter thereon, a method comprising:
- enabling concurrent maintenance of the at least one system component by exchanging concurrent maintenance message signals between the input/output adapter and the system power controller over a second communications path different from the first communications path, so that the system power controller thereby controls power to the system component subject to concurrent maintenance.
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Accused Products
Abstract
In an electrical system, concurrent maintenance of a system component coupled to the system by an adapter on a first communications path is accomplished through the provision of a second communications path to a system power controller, so that concurrent maintenance is not dependent on communications over the first communications path. In particular, concurrent maintenance of a direct access storage device (DASD) coupled to a computer system through a small computer system interconnect (SCSI) bus, an input-output adapter (IOA), a peripheral component interconnect (PCI) bus and a PCI bridge circuit (PCIB), is enabled by providing a IIC serial, point-to-point signal path between the bridge circuit and a system power control network (SPCN) to coordinate quiescing of the SCSI buses and powering down of the DASD.
117 Citations
23 Claims
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1. In an electrical system having a system power controller and at least one system component coupled to the electrical system by a first communications path having a input/output adapter thereon, a method comprising:
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enabling concurrent maintenance of the at least one system component by exchanging concurrent maintenance message signals between the input/output adapter and the system power controller over a second communications path different from the first communications path, so that the system power controller thereby controls power to the system component subject to concurrent maintenance. - View Dependent Claims (2, 3, 4, 5)
building a concurrent maintenance command message including a command and device parameters;
storing the concurrent maintenance command message;
reading the stored concurrent maintenance command message with the system power controller; and
executing the concurrent maintenance command with the system power controller.
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3. The method according to claim 2, wherein the system further has a bus bridging circuit in the first communication path and the second communications path, the bus bridging circuit storing the concurrent maintenance command message from the input/output adapter for the system power controller.
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4. The method according to claim 3, further comprising storing responses from the system power controller to the input/output adapter in the bus bridging circuit.
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5. The method according to claim 1, wherein the electrical system includes a plurality of system components, input/output adapters, and bus bridging circuits, there being a plurality of second communications paths, the method further comprising multiplexing respective concurrent maintenance command messages from the input/output adapters to the system power controller.
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6. An apparatus for enabling concurrent maintenance of a system component coupled by a first communication path to an electrical system, wherein the first communication path includes a system bus, a local bus and a bus bridge circuit bridging the local bus and the system bus, the apparatus comprising:
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a system power controller which controls power to the system component; and
a second communication path which connects the system power controller and the bus bridge circuit, through which concurrent maintenance signals are communicated. - View Dependent Claims (7, 8, 9, 10, 11)
a signaling device which indicates whether the direct access storage device is available for concurrent maintenance;
a PCI interconnection board having at least one PCI slot connector; and
an input/output adapter disposed in the at least one PCI slot connector, the input/output adapter providing a small computer system interconnect (SCSI) bus, the direct access storage device being connected to the small computer system interconnect bus.
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10. The apparatus according to claim 9, wherein the bridge circuit comprises a random access memory, the bridge circuit and the system power controller communicating by reading and writing data and commands to and from the random access memory.
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11. The apparatus according to claim 10, wherein the system power controller comprises a system power control network which controls the signaling device and power to the direct access storage device to enable concurrent maintenance operations.
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12. A method of enabling concurrent maintenance in a computer system having at least one peripheral device coupled by a first bus to an input-output circuit, the input-output circuit coupled to a computer system host processor through a host bus and a host bus bridge circuit, the computer system further having a system power control network which controls power to each component of the computer system, the system power control network being interfaced to the at least one input/output circuit by a second different bus, the method comprising:
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signaling to the input/output circuit a request for concurrent maintenance from the computer system through the host bus and host bridge circuit;
providing a concurrent maintenance message signal to the system power control network over the second bus, with the at least one input/output circuit and the host bridge circuit to enable the system power control network to power down the at least one peripheral device coupled thereto for concurrent maintenance. - View Dependent Claims (13, 14)
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15. In a computer system having a system bus coupled to a plurality of backplanes, each backplane having a local bus connected to a plurality of slot connectors on the respective backplane and at least one bridge circuit bridging the system bus to the backplane local bus, at least some of the slot connectors having input/output adapters inserted therein, at least some of the adapters providing a communications path with a respective direct access storage device, an arrangement for enabling concurrent maintenance comprising:
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a system power control network to control power to components of the system, including direct access storage devices and their respective input/output adapters; and
a communications path to the system power control network from each respective bridge circuit on each respective backplane of the system through which concurrent maintenance communications signals are passed. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
a respective serial bus connected to each bridge circuit;
a multiplexer coupled to each respective serial, point-to-point, single-master single-slave, two-wire bus; and
a bus controller connected to the multiplexer and to the system power control network.
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17. The arrangement according to claim 16, wherein each bridge circuit comprises a random access memory readable and writeable by both the bridge circuit and the system power control network with the concurrent maintenance communications signals.
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18. The arrangement according to claim 17, wherein each local bus comprises a peripheral component interconnect bus, and wherein each bridge circuit comprises a peripheral component interconnect bridge circuit.
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19. The arrangement according to claim 18, wherein each of the input/output adapters providing a communications path with a respective direct access storage device comprise one of:
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a parallel small computer system interconnect bus;
ora serial small computer system interconnect bus.
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20. The arrangement according to claim 19, wherein the bridge circuit random access memory is further able to store information which can be used by the system power control network to uniquely identify computer system components by their physical location, including their enclosure, the backplane within the enclosure, and the slot on the backplane to which they are interfaced.
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21. The arrangement according to claim 20, wherein the information stored in the random access memory further includes the small computer system interconnect bus to which a direct access storage device is connected, which device the direct access storage device is on the small computer system interconnect bus, and which direct access storage device slot the direct access storage device is located in.
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22. The arrangement according to claim 21, wherein each respective serial bus comprises a point-to-point, single-master single-slave, two-wire bus which carries clock signals.
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23. The arrangement according to claim 22, further comprising at least one of:
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signaling circuitry which indicates whether a direct access storage device is available for concurrent maintenance; and
a direct access storage device interlocking mechanism which unlocks the direct access storage device for concurrent maintenance.
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Specification