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Interconnection Between One-Byte Channel and Two-Byte Control Unit

IP.com Disclosure Number: IPCOM000047316D
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Meifert, KA: AUTHOR

Abstract

A channel data path that is one byte wide is connected to a control unit data path that is two bytes wide. The interconnecting system has two buffer chains that are each one byte wide and each hold a few bytes of data. When the channel sends data on its one-byte data path, successive bytes are loaded alternately into the two buffer chains and the output of each chain is supplied in parallel to the two one-byte paths to the control units. When the control unit transmits data to the channel, data is loaded in parallel from the two-byte-wide bus of the control unit into the two buffer chains. Data is selected alternately at the output of the two buffer chains and is applied to the one-byte-wide path to the channel. The control unit and the channel are also conventionally connected by one-byte-wide tag lines.

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Interconnection Between One-Byte Channel and Two-Byte Control Unit

A channel data path that is one byte wide is connected to a control unit data path that is two bytes wide. The interconnecting system has two buffer chains that are each one byte wide and each hold a few bytes of data. When the channel sends data on its one-byte data path, successive bytes are loaded alternately into the two buffer chains and the output of each chain is supplied in parallel to the two one-byte paths to the control units. When the control unit transmits data to the channel, data is loaded in parallel from the two-byte-wide bus of the control unit into the two buffer chains. Data is selected alternately at the output of the two buffer chains and is applied to the one-byte-wide path to the channel. The control unit and the channel are also conventionally connected by one-byte-wide tag lines. Signals on the tag busses are sampled by the interconnecting circuit to control the flow of data through the buffer chains. When the tag bus signifies that the channel is sending a command to the control unit, the command is routed to a particular one of the data busses of the channel. When data is being transmitted from the channel and the controller, the signals on the tag bus are used to assign bytes to the two chains in an appropriate sequence. Conversely, when the control unit puts parallel bytes into both buffer chains in parallel, the controls transfer data in the appropriate sequence to t...