Data processing system having a bus command generated by one subsystem on behalf of another subsystem

Claim 2

A data processing system comprising: a system bus; a first subsystem coupled to said system bus for generating and transmitting over said bus a first command and a second command, both requiring a response command; a second subsystem coupled to said system bus for receiving said first and said second commands and generating a response command; a plurality of third subsystems coupled to said bus; each one of said first and third subsystems monitoring communications broadcast on said bus and responsive to a command field identifying said one subsystem for accepting the communication broadcast on said bus; said first command including a first field identifying said first subsystem, a second field identifying said second subsystem and a third field specifying the action said second subsystem is to perform, said second subsystem generating and broadcasting over said bus a first response command including a fourth field identifying said first subsystem; and said second command including a first field identifying on of said third subsystems, a second field identifying said second subsystem and a third field specifying the action said second subsystem is to perform, said second subsystem generating and broadcasting over said bus a second response command including a fourth field identifying said one third subsystem.

Claim 3

The system of claim 1 wherein said first subsystem receives an acknowledge signal from said second subsystem when said second subsystem receives said first or said second commands.

Claim 4

The system of claim 2 wherein said first subsystem includes time calculation means for verifying that said first response command is received by said first subsystem within a predetermined time interval calculated from generation of said first command if said first field identifies said first subsystem.

Claim 5

The system of claim 3 wherein said time calculation means is disabled by said acknowledge signal from said second subsystem when said second command is sent by said first subsystem.

Claim 6

A data processing system comprising: a system bus; a first subsystem coupled to said system bus for generating and transmitting over said bus a command requiring a response command; a second subsystem coupled to said system bus for receiving said command and generating and broadcasting over said bus said response command; said command including a first field identifying a certain third subsystem of a plurality of third subsystems, a second field identifying said second subsystem and a third field specifying the action said second subsystem is to perform; said response command including a field identifying the third subsystem identified by said first field; said third subsystems coupled to said system bus, each one of said third subsystems monitoring communications broadcast on said bus and responsive to a command field identifying said one subsystem for accepting the communication broadcast on said bus, the one of said subsystems identified by said field in said response command receiving said response command.

Claim 7

A data processing system comprising: a system bus; a first subsystem coupled to said system bus for generating and transmitting over said bus a command requiring a response command; a second subsystem coupled to said system bus for receiving said command and generating and broadcasting over said bus said response command; said command including a first field identifying a certain third subsystem of a plurality of third subsystems, a second field identifying said second subsystem and a third field specifying the action said second subsystem is to perform; said response command including a field identifying the third subsystem identified by said first field; said third subsystems coupled to said system bus, each one of said third subsystems monitoring communications broadcast on said bus and responsive to a command field identifying said one subsystem for accepting the communication broadcast on said bus, the one of said subsystems identified by said field in said response command receiving said response command.

Claim 8

The system of claim 5 wherein said first subsystem receives an acknowledge signal from said second subsystem when said second subsystem receives said command.

Claim 9

The subsystem of claim 6 wherein said first subsystem includes time calculation means for verifying that said response command is received by said first subsystem within a predetermined time interval calculated from generation of said command of said first subsystem if said first field identifies said first subsystem, said time calculation means being responsive to said acknowledge signal for disabling said time calculation means when said first field identifies said certain third subsystem.

Claim 10

A data processing system comprising: a system bus; management means coupled to said system bus for generating and transmitting over said system bus a memory reference command including a first and a second control signal, a channel number and a memory address; memory means coupled to said system bus and responsive to said first and said second control signals for reading the contents of a memory location specified by said memory address and generating and broadcasting over said system bus a second half bus cycle command including said channel number and the contents of said memory location; and plurality of subsystem means coupled to said system bus, each one of said subsystem means monitoring communications broadcast on said bus and responsive to a channel number identifying said one subsystem means for accepting the communication broadcast on said bus, the one of said subsystem means identified by the channel number of said second half bus cycle command receiving said second half bus cycle command and storing the contents of said memory location, whereby the management means may request data retrieval for any certain subsystem means of the plurality of subsystem means by providing and transmitting over said bus the certain subsystem means' channel number with said control signals and said memory address, said management means receiving an acknowledge signal from said memory means when said memory means receives said memory reference command, and said management means including time calculation means for verifying that said second half bus cycle command is received within a predetermined time interval calculated from generation of said memory reference command if said channel number identifies said management means.

Claim 11

A data processing system comprising: a system bus; management means coupled to said system bus for generating and transmitting over said system bus a memory reference command including a first and a second control signal, a channel number and a memory address; memory means coupled to said system bus and responsive to said first and said second control signals for reading the contents of a memory location specified by said memory address and generating and broadcasting over said system bus a second half bus cycle command including said channel number and the contents of said memory location; and plurality of subsystem means coupled to said system bus, each one of said subsystem means monitoring communications broadcast on said bus and responsive to a channel number identifying said one subsystem means for accepting the communication broadcast on said bus, the one of said subsystem means identified by the channel number of said second half bus cycle command receiving said second half bus cycle command and storing the contents of said memory location, whereby the management means may request data retrieval for any certain subsystem means of the plurality of subsystem means by providing and transmitting over said bus the certain subsystem means' channel number with said control signals and said memory address, said management means receiving an acknowledge signal from said memory means when said memory means receives said memory reference command, and said management means including time calculation means for verifying that said second half bus cycle command is received within a predetermined time interval calculated from generation of said memory reference command if said channel number identifies said management means.

Claim 12

The system of claim 8 wherein said time calculation means is disabled by said acknowledge signal when said channel number identifies one of said subsystem means.