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Daisy Chain Control for Adapters Performing Adapter-Initiated Operations in a Central Control Unit Via an I/O Bus

IP.com Disclosure Number: IPCOM000042919D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Billian, A: AUTHOR [+2]

Abstract

In a communication controller including a Central Control Unit (CCU) and several adapters connected to the CCU via an I/O Bus, the arrangement shown above improves the propagation of the Channel Grant signal sent by the CCU to service the adapter requests for adapter-initiated operations (AIO) on the I/O Bus in order to increase the performance of these operations. A simple logic is implemented in the redrive cards which are used to repower the I/O Bus. The Channel Grant signal is propagated directly to the first adapter, which has a current channel request to the CCU, without taking into account the ones without any request. In the communication controller, the adapters and redrive cards are arranged in a pyramidal structure.

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Daisy Chain Control for Adapters Performing Adapter-Initiated Operations in a Central Control Unit Via an I/O Bus

In a communication controller including a Central Control Unit (CCU) and several adapters connected to the CCU via an I/O Bus, the arrangement shown above improves the propagation of the Channel Grant signal sent by the CCU to service the adapter requests for adapter-initiated operations (AIO) on the I/O Bus in order to increase the performance of these operations. A simple logic is implemented in the redrive cards which are used to repower the I/O Bus. The Channel Grant signal is propagated directly to the first adapter, which has a current channel request to the CCU, without taking into account the ones without any request. In the communication controller, the adapters and redrive cards are arranged in a pyramidal structure. Two adapters A are provided on a board B with a redrive card BR per adapter board, repowering the I/O Bus for the two adapters. The boards are arranged in frames F, with a redrive card FR repowering the I/O Bus from the previous frame and distributing it to the board redrive cards inside the frame. The frame redrive and board redrive cards are identical. The adapters on a board place their channel requests on a single adapter channel request (A. CH. REQ.) line. This line is repowered by the board redrive card BR through receiver (R) and driver (D). All board redrive cards BR within a frame place the repowered adapter channel request on a single board channel request (B. CH. REQ.), line which line is repowered by the frame redrive card FR. All frame redrive cards place the repowered board channel request on a sin...