International Business Machines Corporation

Peter N James

Stefan P Jackowski

Mark J Wolski

James T Moyer

Richard L Hester

Robert G Rush

Joao B De Azevedo, Jr

Gregory S Ulsh

A system structured to transfer control information between an IFA (I/O interface adapter) and an I/O processor, and I/O data between an IFA and a CDB (channel data buffer) has separate interfaces for these transfers. The control interface includes a multi-mode, bidirectional control data bus, a control mode bus for establishing the mode of the bus, and a check interface on which the IFA provides error information. The data interface includes a multi-mode, bidirectional data transfer bus, respective SYNC and ACCEPT lines for transferring time-phased control signals to establish the mode of the data transfer bus, and a parity line to indicate to the IFA the parity of the SYNC and ACCEPT lines.

Multimode data system for transferring control and data information in

Provision is made for conducting an I/O channel diagnostic test by using a first I/O channel in a test mode to provide a sequence of test signals to a second I/O channel. The second I/O channel responds to the test sequence by producing a series of data transfer protocol signals which are conducted to the first channel. In the first channel, the series of data transfer protocol signals are used to check operation of the second channel.

Channel hardware diagnostic apparatus and method

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Algonquin, IL, United States of America

Peter N James