Expandable communication system using data concentration

Claim 1

A communication system, comprising: a host computer, including: a system bus, memory connected to said system bus, wherein said memory includes a data buffer for sending and receiving data; a plurality of I/O devices; a data concentrator, including: a plurality of device communication ports, each said device communication port being connected to a corresponding one of said plurality of I/O devices, for sending data to and receiving data from said I/O devices, a communication link for sending and receiving data and commands in a packet comprised of a predetermined number of bits, wherein said packet may be one of a predetermined number of including data packets, and wherein each packet includes a frame-type field indicative of the packet type, and wherein if said packet is a data packet, said packet further includes an address field containing a device communication port number indicative of one of said plurality of device communication ports, and a data field containing data sent from said communication link of said data concentrator to be sent to an I/O device connected to said device communication port or said data field containing data sent from said I/O device connected to said device communication port to be sent on said communication link, and processor means connected to said communication link and said plurality of device communication ports for receiving said packets from said communication link, determining the packet type from said frame-type field of said packet; and if said packet is a data packet, sending said data in said data field to the device communication port indicated by the device communication port number in said address field, and for receiving data from each of said I/O devices connected to one of said plurality of device communication ports, identifying the corresponding device communication port number, assembling a data packet, and sending said data packet onto said communication link; and a host adapter connected to said host computer system bus, said host adapter including: a plurality of I/O ports, each said I/O port including: a device receiver-transmitter for sending data to and receiving data from an I/O device, a communication link being capable of sending and receiving said predetermined sized packets through said communication link, and switching means connected to said device receiver-transmitter and said communication link, wherein if one of said plurality of I/O devices is connected to said I/O port, said switching means couples said device receiver-transmitter to said I/O device, and if said data concentrator communication link is connected to said I/O port, said switching means couples said host adapter communication link to said data concentrator communication link, and processor means coupled to said plurality of I/O ports and said host computer system bus for transferring data between said host computer data buffer and said host adapter I/O ports, wherein if one of said plurality of I/O devices is connected to one of said plurality of I/O ports, said processor and transfer means receives input data from said I/O device and transfers said input data to said host computer data buffer, and transfers output data from said host computer data buffer to said I/O device through said I/O port, and wherein if said data concentrator is coupled to said I/O port, said processor and transfer means receives data packets from said I/O port communication link, places the data from said data field into said host computer data buffer, and retrieves data from said host computer data buffer intended for one of said plurality of I/O devices coupled to said host adapter through said data concentrator, assembles a data packet and sends said data packet through said I/O port communication link to said data concentrator.