Asynchronous multi-communication bus sequence
AssigneeHoneywell Information Systems Inc.
InventorsKenneth E. Bruce, Ralph M. Lombardo, Jr., Bruce H. Tarbox, John W. Conway
Life of this patent
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Abstract
An intersystem communication control system in an intersystem link (ISL) unit is provided to accommodate the simultaneous bidirectional transfer of binary coded information between communication busses in a data processing system, wherein the plural communication busses are electrically interconnected by ISL unit twins, and information may be transferred between plural communication busses asynchronously.
Claims21
An intersystem communication control system electrically connecting plural communication busses in a data processing system wherein each of said plural communication busses provides a common information path to plural data processing units including memory units, peripheral control units, central processing units and intersystem link units (ISLs) for accommodating simultaneous bidirectional binary coded information transfers between a local one of said plural communication busses and a remote one of said plural communication busses, which comprises:
- (a) local bus control logic means in a local one of said ISL units in electrical communication with said local bus and responsive to a BSDCNN signal on said local bus for identifying those bus cycle requests received from said local bus for which said local ISL unit shall respond;
- (b) local cycle control logic means responsive to activity bit control signals from said local ISL unit and a remote one of said ISL units in electrical communication with said remote bus for controlling the transfer of local binary coded information received from said local bus and said remote bus to said remote ISL unit and routing through said local ISL unit binary coded information received from said remote ISL unit;
- (c) local ISL interface register means responsive to said local cycle control logic means for storing said local binary coded information for transfer to said remote ISL unit, thereby freeing said local cycle control logic means for receiving remote binary coded information from said remote ISL unit to effect a simultaneous bidirectional information transfer;
- (d) remote bus control logic means in said remote said ISL unit responsive to a BSDCNN signal on said remote bus for identifying those bus cycle requests received from said remote bus for which said remote ISL unit shall respond;
- (e) remote cycle control logic means responsive to activity bit control signals from said local ISL unit and said remote ISL unit for controlling the transfer of remote binary coded information received from said local bus and said remote bus to said local ISL unit and routing through said remote ISL unit said local binary coded information received from said local ISL unit;
- and
- (f) remote ISL interface register means responsive to said remote cycle control logic means for storing said remote binary coded information for transfer to said local ISL unit, thereby freeing said remote cycle control logic means for receiving said local binary coded information from said local ISL unit to effect a simultaneous bidirectional information transfer.
In a data processing network including a plurality of data processing systems wherein each system is provided with common bus means for exchanging information between individual devices within said system, intersystem communication control apparatus comprising:
- first intersystem link (ISL) means coupled to a first one of said common bus means;
- and
- second intersystem link (ISL) means coupled to a second one of said common bus means and to said first ISL means;
- said first ISL means including memory means and transfer control means responsive to a data write request received from said first common bus means and directed to said second common bus means, said transfer control means operating to load address and data information from said first common bus means into said memory means and to transfer said information from said memory means to said second ISL means;
- and
- said second ISL means including means for receiving said address and data information and for transmitting said information onto said second common bus means, whereby said data information is written into data storage means included within a device coupled to said second common bus means, said data storage means being selected in accordance with said address information.
In a data processing network including a plurality of data processing systems wherein each system is provided with common bus means for exchanging information between individual devices within said system, intersystem communication control apparatus comprising:
- first intersystem link (ISL) means coupled to a first one of said common bus means;
- and
- second intersystem link (ISL) means coupled to a second one of said common bus means and to said first ISL means;
- said first ISL means including request memory means, request load control means responsive to a data read request received from said first common bus means and directed to said second common bus means for loading source identification information from said first common bus means into said request memory means, and request transfer control means also responsive to said data read request for transferring first address information received from said first common bus means to said second ISL means;
- and
- said second ISL means including means for receiving said first address information from said first ISL means and means for transmitting said first address information along with an ISL identification code and a response requested signal onto said second common bus means, whereby a data read request is applied to data storage means coupled to said second common bus means, said data storage means being selected in accordance with said first address information.
In a data processing network including a plurality of data processing systems wherein each system is provided with common bus means for exchanging information between individual devices within said system, intersystem communication control apparatus comprising:
- first intersystem link (ISL) means coupled to a first one of said common bus means;
- and
- second intersystem link (ISL) means coupled to a second one of said common bus means and to said first ISL means;
- said first ISL means including memory means and control means responsive to a remote data read request issued on said first common bus means by a requesting device for storing the return address of said requesting device in said memory means and for transferring the address of a target device on said second common bus means to said second ISL means;
- said second ISL means including means for receiving said target address from said first ISL means and for transmitting said target address, together with a local read request, onto said second common bus means, means for receiving response data from said target device in response to said local read request, and means for transmitting said response data together with a response command to said first ISL device;
- and
- said first ISL means further including means for receiving said response data and response command from said second ISL means and means activated by said response command for transmitting said response data and said return address obtained from said memory means onto said first common bus means, whereby said response data is supplied to said requesting device in response to said remote data read request.
Dependencies are inferred from the claim text.