Duplex data processing system with programmable bus configuration
First Claim
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1. A duplex data processing system comprising:
- two processor systems, one of which is operating as an active system and the other of which is operating as a stand-by system, respectively, in a duplex system mode of operation, each processor system including a central processing unit (CPU), a memory unit and an input/output controller interconnected by a CPU bus, the memory units in the two processor systems operating with the same address mapping;
a cross connection bus provided between said two processor systems; and
bus connecting means provided in each of said processor systems and connected to the CPU bus within said processor system and to said cross connection bus, for disconnecting said two processor systems to establish a Separate mode of operation in which said two processor systems operate independently and for interconnecting said two processor systems via said cross connecting bus to establish a Duplex mode of operation in which said two processor systems are arranged in duplex configuration such that the CPU of the active system can access the respective memory units in both processor systems simultaneously in response to commands from the CPU in the active processor system, each bus connecting means including means operative in said Separate mode of operation for disconnecting the CPU bus in its processor system from the CPU bus in the other processor system by breaking the connection between the CPU bus in its processor system and said cross connection bus, and means operative in said Duplex mode of operation for connecting the CPU bus in its processor system to the CPU bus in the other processor system by making the connection of its CPU bus through said cross connecting bus to the CPU bus in the other processor system.
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Abstract
A duplex data processing system includes two processors each provided with a bus connecting unit which disconnects the associated CPU bus from the cross connection bus in a separate mode or connects the CPU bus to the cross connection bus in a duplex mode. The system operates with a logically unified CPU bus through the connection of the internal CPU buses by the two bus connecting units in both processors.
51 Citations
7 Claims
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1. A duplex data processing system comprising:
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two processor systems, one of which is operating as an active system and the other of which is operating as a stand-by system, respectively, in a duplex system mode of operation, each processor system including a central processing unit (CPU), a memory unit and an input/output controller interconnected by a CPU bus, the memory units in the two processor systems operating with the same address mapping; a cross connection bus provided between said two processor systems; and bus connecting means provided in each of said processor systems and connected to the CPU bus within said processor system and to said cross connection bus, for disconnecting said two processor systems to establish a Separate mode of operation in which said two processor systems operate independently and for interconnecting said two processor systems via said cross connecting bus to establish a Duplex mode of operation in which said two processor systems are arranged in duplex configuration such that the CPU of the active system can access the respective memory units in both processor systems simultaneously in response to commands from the CPU in the active processor system, each bus connecting means including means operative in said Separate mode of operation for disconnecting the CPU bus in its processor system from the CPU bus in the other processor system by breaking the connection between the CPU bus in its processor system and said cross connection bus, and means operative in said Duplex mode of operation for connecting the CPU bus in its processor system to the CPU bus in the other processor system by making the connection of its CPU bus through said cross connecting bus to the CPU bus in the other processor system. - View Dependent Claims (2, 3, 4, 5, 7)
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6. A duplex data processing system with programmable bus configuration comprising:
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a pair of processor systems, each processor system including a central processing unit (CPU), a memory unit, an input/output controller, and a CPU bus connecting said central processing unit, memory unit and input/output controller, the memory units in the pair of processor systems operating with the same address mapping; a cross connecting bus provided between said pair of processor systems; and bus connecting means provided in each of said processor systems and connected to said CPU bus and said cross connecting bus and adapted to operate in a Separate mode in which said CPU buses of said pair of processor systems are separated and in a Duplex mode in which one processor system operates as an active processor system and the other processor system operates as a stand-by processor system and each CPU of said pair of processor systems is connected via said cross connecting bus so that the central processing unit in the active processor system can access the memory units in both processor systems simultaneously in response to a command from said central processing unit in said one processor system, said bus connecting means including means operating in said Separate mode for disconnecting the CPU bus from said cross connecting bus, and in said Duplex mode for connecting said CPU buses of said processor systems through said cross connecting bus to form a logically unified system.
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Specification