RESERVED DEVICE ACCESS CONTENTION REDUCTION
First Claim
1. A computer program product for reducing reserved device access contention at a control unit in communication with a plurality of operating systems via one or more channels, the computer program product comprising:
- a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;
receiving a command message at the control unit from a first operating system of the plurality of operating systems via the one or more channels, wherein the command message includes an I/O operation command for a device in communication with the control unit;
receiving a device busy indicator from the device, wherein the device busy indicator notifies the control unit that the device is reserved by a second operating system of the plurality of operating systems;
queuing the command message on a device busy queue in response to the device busy indicator;
monitoring the device for a device end indicator, wherein the device end indicator notifies the control unit that the device is ready to receive a new I/O operation command; and
servicing the device busy queue to perform the I/O operation command in response to the device end indicator.
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Accused Products
Abstract
A computer program product, an apparatus, and a method for reducing reserved device access contention at a control unit in communication with a plurality of operating systems via one or more channels are provided. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method that includes receiving a command message at the control unit from a first operating system, including an I/O operation command for a device. A device busy indicator is received, indicating that a second operating system has reserved the device. The command message is queued on a device busy queue in response to the device busy indicator. The control unit monitors for a device end indicator. The device busy queue is serviced to perform the I/O operation command in response to the device end indicator.
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Citations
20 Claims
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1. A computer program product for reducing reserved device access contention at a control unit in communication with a plurality of operating systems via one or more channels, the computer program product comprising:
a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising; receiving a command message at the control unit from a first operating system of the plurality of operating systems via the one or more channels, wherein the command message includes an I/O operation command for a device in communication with the control unit; receiving a device busy indicator from the device, wherein the device busy indicator notifies the control unit that the device is reserved by a second operating system of the plurality of operating systems; queuing the command message on a device busy queue in response to the device busy indicator; monitoring the device for a device end indicator, wherein the device end indicator notifies the control unit that the device is ready to receive a new I/O operation command; and servicing the device busy queue to perform the I/O operation command in response to the device end indicator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for reducing reserved device access contention, the apparatus comprising:
a control unit in communication with a plurality of operating systems via one or more channels, the control unit performing a method comprising; receiving a command message at the control unit from a first operating system of the plurality of operating systems via the one or more channels, wherein the command message includes an I/O operation command for a device in communication with the control unit; receiving a device busy indicator from the device, wherein the device busy indicator notifies the control unit that the device is reserved by a second operating system of the plurality of operating systems; queuing the command message on a device busy queue in response to the device busy indicator; monitoring the device for a device end indicator, wherein the device end indicator notifies the control unit that the device is ready to receive a new I/O operation command; and servicing the device busy queue to perform the I/O operation command in response to the device end indicator. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for reducing reserved device access contention at a control unit in communication with a plurality of operating systems via one or more channels, the method comprising:
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receiving a command message at the control unit from a first operating system of the plurality of operating systems via the one or more channels, wherein the command message includes an I/O operation command for a device in communication with the control unit; receiving a device busy indicator from the device, wherein the device busy indicator notifies the control unit that the device is reserved by a second operating system of the plurality of operating systems; queuing the command message on a device busy queue in response to the device busy indicator; monitoring the device for a device end indicator, wherein the device end indicator notifies the control unit that the device is ready to receive a new I/O operation command; and servicing the device busy queue to perform the I/O operation command in response to the device end indicator. - View Dependent Claims (18, 19, 20)
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Specification