Apparatus for transferring blocks of information from one node to a second node in a computer network

• US 4,777,595 A
• Filed: 03/24/1986
• Issued: 10/11/1988
• Est. Priority Date: 05/07/1982
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Stewart, Robert E., Fuller, Samuel, Strecker, William D.
• Primary Examiner(s): Shaw, Gareth D.
• Assistant Examiner(s): Dorsey, Daniel K.
• Application Number:
  US06/843,937
• Time in Patent Office: 932 Days
• Field of Search: 364/200 MS file, 364/900 MF file
• US Class Current: 709/236
• CPC Class Codes: G06F 15/167 using a common memory, e.g. mailbox
• CPC Class Codes: G06F 15/177 Initialisation or configuration control processor initialisation G06F9/4405

Abstract

Method and apparatus for transfer of packet-type information from the memory (24B) of one node (14) in a computer network to the memory (24C) of another node (16) in the network. The invention is of particular utility in transfers over serial buses (e.g., 18). Packets are sent from a named memory buffer (25A) at a first node (14) to a named memory buffer (25C) at a second node (16), allowing random access by the first node to the memory of the second node without either node having to have knowledge of the memory structure of the other, the source and destination buffer names are contained right in the transmitted packet.

The first node (14) can both write to and read from the second node (16). An opcode (40A) sent in each packet signifies whether a read or write operation is to be performed. For reading from the second node, the opcode actually causes the second node to write back to the first node; in this situation, the second node, upon detecting the appropriate opcode, places the remainder of the received packet on a command queue (202), to be executed with the commands locally generated at the second node, without need for host interruption.

Claims

1. A digital data processing system including a source node and a destination node, each including a host computer, and a common bus, said source node further including a source buffer means for storing a block of information to be transferred, said source buffer means being identified by a source buffer name, and said destination node further including destination buffer means for receiving a block of information, said destination buffer being identified by a destination buffer name, and said destination node including means for identifying the name of the destination buffer means to the source node;

A. said source node further including;

i. message assembly means connected to said source buffer means for assembling a packet comprising a plurality of fields including;

(a) an information field including information from said source buffer means,

(b) a packet type field containing a packet type that identifies the packet as containing information for the destination buffer means or as containing a command to be executed by said destination node,

(c) a destination name field including the name of said destination buffer means,

ii. source port means connected to said message assembly means and said common bus responsive to the generation of a packet by said message assembly means for transmitting the packet over said common bus

B. said second node including;

i. destination port means connected to said common bus for rceiving packets from said bus;

ii. means for selectively writing a received packet to the destination memory buffer comprising;

(a) packet type decoding means for decoding the contents of the packet type field in the received packet to determine whether the packet contains information for the destination buffer means; and

(b) directing means connected to said packet type decoding means responsive to the packet type decoding means determining that the packet contains information for the destination buffer means and further responsive to the contents of the destination name field for directing the contents of the packet to the identified destination buffer.

2. A data processing system as defined in claim 1 wherein each packet generated by said message assembly means includes an offset field whose contents identify an offset within the destination buffer into which the information in the information field is to be received, said directing means being further responsive to the contents of said offset field for directing the contents of the information field of the packet to the portion of said destination buffer identified by the contents of said offset field.

3. A data processing system as defined in claim 1 wherein said message assembly means includes means for generating a plurality of packets to transfer the information in said source buffer means, each packet generated by said message assembly means further including a last packet field which contains a last packet flag which is set when the packet is the last packet for the message.

4. A data processing system as defined in claim 3 wherein said destination port means further includes means for generating a confirmation packet for transmission to said source node in response to the receipt of a packet from said source node in which said last packet flag is set.

5. A data processing system as defined in claim 4 wherein each packet generated by said message assembly means further includes a packet sequence field whose contents relate to the number of the packet since the beginning of the message, said destination port means further including sequence counter means, comparison means responsive to the receipt of a packet for comparing the value from the sequence counter means to the contents of the packet sequence field to verify that the packet is the proper packet in the sequence, and incrementing means for incrementing said sequence counter means in response to the receipt of each packet to identify the sequence number of the next expected packet.

6. A data processing system as defined in claim 1 wherein the destination means further includes command execution means for executing a command when said packet type field indicates that the packet contains a command to be executed by said destination node.

7. A data processing system as defined in claim 6 wherein one command requests the destination node to send information from said destination buffer means to said source node, said source node further including source buffer means identified by a source buffer name, said source node including means for identifying the name of the source buffer means to the destination node, said destination node further including message assembly means connected to said destination buffer means for assembling a packet comprising a number of fields including:

A. an information field including information from said destination buffer means, and

B. a source name field including the name of said source buffer means,

said destination port means further including means connected to said message assembly means for transmitting the packets generated by said message assembly means over said common bus.

8. A data processing system as defined in claim 7 in which said source port means further includes means for receiving packets from the common bus and source node directing means connected to said source port means and responsive to the contents of the source name field for directing the contents of the packet to the identified source buffer means.

9. A data processing system as defined in claim 8 wherein said destination message assembly means includes means for generating a plurality of packets to transfer a message comprising the information in said destination buffer means, each packet generated by said message assembly means further including a last packet field which contains a last packet flag which is set when the packet is the last packet for the message.

10. A data processing system as defined in claim 9 wherein said source port means further includes means for generating a confirmation packet for transmission to said destination node in response to the receipt of a packet from said destination node in which said last packet flag is set.

11. A source node for connection to a common bus in a digital data processing system including a destination node connected to said common bus, each node including a host computer, and a common bus, said source node further including a source buffer means for storing a block of information to be transferred, said source buffer means being identified by a source buffer name, and said destination node further including destination buffer means for receiving a block of information, said destination buffer being identified by a destination buffer name, and said destination node including means for identifying the name of the destination buffer means to the source node, said source node further including:

i. message assembly means connected to said source buffer means for assembling a packet comprising a plurality of fields including;

(a) an information field including information from said source buffer means,

(b) a packet type field containing a packet type that identifies the packet as containing information for the destination buffer means or as containing a command to be executed by said destination node,

(c) a destination name field including the name of said destination buffer means, and

ii. source port means connected to said message assembly means and said common bus responsive to the generation of a packet by said message assembly means for transmitting the packet over said common bus.

12. A source node as defined in claim 11 wherein each packet generated by said message assembly means further includes an offset field whose contents identify an offset within the destination buffer into which the information in the information field is to be received.

13. A source node as defined in claim 11 wherein said message assembly means includes means for generating a plurality of packets to transfer the information in said source buffer means, each packet generated by said message assembly means further including a last packet field which contains a last packet flag which is set when the packet is the last packet for the message.

14. A source node defined in claim 13 wherein each packet generated by said message assembly means further includes a packet sequence field whose contents relate to the number of the packet since the beginning of the message.

15. A source node as defined in claim 11 wherein one command requests the destination node to send information from said destination buffer means to said source node, said source node further including source buffer means identified by a source buffer name and means for identifying the name of the source buffer means to the destination node.

16. A source node as defined in claim 15 in which said destination node includes means for transmitting packets each including an information field and a source name field including the name of the source buffer means, said source port means further including means for receiving packets from the common bus and source node directing means connected to said source port means and responsive to the contents of the source name field for directing the contents of the packet to the identified source buffer means.

17. A source node as defined in claim 16 wherein said destination node generates messages comprising a plurality of packets each packet further including a last packet field which contains a last packet flag which is set when the packet is the last packet for the message, said source port means further including means for generating a confirmation packet for transmission to said destination node in response to the receipt of a packet from said destination node in which said last packet flag is set.

18. A destination node for connection to a digital data processing system including a source node, each including a host computer, and a common bus, said source node further including a source buffer means for storing a block of information to be transferred, said source buffer means being identified by a source buffer name, and said destination node further including destination buffer means for receiving a block of information, said destination buffer being identified by a destination buffer name, and said destination node further including means for identifying the name of the destination buffer means to the source node;

said source node assembling a packet comprising a plurality of fields including (a) an information field including information from said source buffer means, (b) a packet type field containing a packet type that identifies the packet as containing information for the destination buffer means or as containing a command to be executed by said destination node and (c) a destination name field including the name of said destination buffer means and transmitting the packet over said common bus;

said destination node further including;

i. destination port means connected to said common bus for receiving packets from said bus;

ii. means for selectively writing a received packet to the destination memory buffer comprising;

(a) packet type decoding means for decoding the contents of the packet type field in the received packet to determine whether the packet contains information for the destination buffer means; and

(b) means connected to said packet type decoding means responsive to the packet type decoding means determining that the packet contains information for the destination buffer means and further responsive to the contents of the destination name field for directing the contents of the packet to the identified destination buffer.

19. A destination node as defined in claim 18 wherein each packet includes an offset field whose contents identify an offset within the destination buffer into which the information in the information field is to be received, said directing means being further responsive to the contents of said offset field for directing the contents of the information field of the packet to the portion of said destination buffer identified by the contents of said offset field.

20. A destination node as defined in claim 18 wherein said source node generates messages comprising a plurality of packets to transfer the information in said source buffer means, each packet further including at last packet field which contains a last packet flag which is set when the packet is the last packet for the message, said destination port means further including means for generating a confirmation packet for transmission to said source node in response to the receipt of a packet from said source node in which said last packet flat is set.

21. A destination node as defined in claim 20 wherein each packet generated by said source node further includes a packet sequence field whose contents relate to the number of the packet since the beginning of the message, said destination port means further including sequence counter means, comparison means responsive to the receipt of a packet for comparing the value from the sequence counter means to the contents of the packet sequence field to verify that the packet is the proper packet in the sequence, and incrementing means for incrementing said sequence counter means in response to the receipt of each packet to identify the sequence number of the next expected packet.

22. A destination node as defined in claim 21 wherein the destination means further includes command execution means for executing a command when said packet type field indicates that the packet contains a command to be executed by said destination node.

23. A destination node as defined in claim 22 wherein one command requests the destination node to send information from said destination buffer means to said source node, said source node further including source buffer means identified by a source buffer name, said source node including means for identifying the name of the source buffer means to the destination node, said destination node further including message assembly means connected to said destination buffer means for assembling a packet comprising a number of fields including:

A. an information field including information from said destination buffer means, and

B. a source name field including the name of said source buffer means,

said destination port means further including means connected to said message means for transmitting the packets generated by said message assembly means over said common bus.

24. A destination node as defined in claim 23 wherein said destination message assembly means includes means for generating a message comprising a plurality of packets to transfer the information in said destination buffer means, each packet generated by said message assembly means further including a last packet field which contains a last packet flat which is set when the packet is the last packet for the message.

25. A node for connection to digital data processing system including a plurality of nodes, each including a host computer, attached to a common bus, said node further including a source buffer means for storing a block of information to be transferred, said source buffer means being identified by a source buffer name, and destination buffer means for receiving a block of information, said destination buffer means identified by a destination buffer name;

said data processing system further including at least one other node also including a destination buffer means identified by a destination buffer name and means for identifying the destination buffer names to all of said nodes, said node further including;

A. source means comprising;

i. message assembly means connected to said source buffer means for assembling a packet comprising a plurality of fields including;

(a) an information field including information from said source buffer means,

(c) a packet type field containing a packet type that identifies the packet as containing information for the destination buffer means or as containing a command to be executed by said destination node

(b) a destination name field including the name of a destination buffer means,

ii. source port means for connection to said message assembly means and said common bus responsive to the generation of a packet by said message assembly means for transmitting the packet over said common bus;

B. destination means comprising;

i. destination port means for connection to said common bus for receiving packets from said bus;

ii. means for selectively writing a received packet to the destination memory buffer comprising;

(a) packet type decoding means for decoding the contents of the packet type field in the received packet to determine whether the packet contains information for the destination buffer means; and

(b) means connected to said packet type decoding means responsive to the packet type decoding means determining that the packet contains information for the destination buffer means and further responsive to the contents of the destination name field for directing the contents of the packet to the identified destination buffer.

26. A node as defined in claim 25 wherein each packet includes an offset field whose contents identify an offset within the destination buffer into which the information in the information field is to be received, said directing means being further responsive to the contents of said offset field for directing the contents of the information field of the packet to the portion of said destination buffer identified by the contents of said offset field.

27. A node as defined in claim 25 wherein said message assembly means includes means for generating a plurality of packets to transfer the information in said source buffer means, each packet generated by said message assembly means further including a last packet field which contains a last packet flag which is set when the packet is the last packet for the message.

28. A node as defined in claim 27 in which at least one other node in said data processing system generates and transmits messages including packets each of which includes a last packet flag which is set when the packet is the last packet for the message, said destination port means further including means for generating a confirmation packet for transmission in response to the receipt of a packet in which said last packet flag is set.

29. A node as defined in claim 28 wherein each packet generated by said message assembly means further includes a packet sequence field whose contents relate to the number of the packet since the beginning of the message.

30. A node as defined in claim 29 wherein at least one other node in said data processing system generates and transmits messages including packets each of which includes a packet sequence field whose contents relate to the number of the packet since the begining of the message, said destination port means further including sequence counter means, comparison means responsive to the receipt of a packet for comparing the value from the sequence counter means to the contents of the packet sequence field to verify that the packet is the proper packet in the sequence, and incrementing means for incrementing said sequence counter means in response to the receipt of each packet to identify the sequence number of the next expected packet.

31. A node as defined in claim 25 wherein the destination means further includes command execution means for executing a command when said packet type field indicates that the packet contains a command to be executed.

32. A node as defined in claim 31 wherein one command requests the node to send information from said destination buffer means to the commanding node which sent the command, said commanding node further including commanding buffer means identified by a command buffer name, said commanding node including means for identifying the name of the commanding buffer means to the node, said node further including message assembly means connected to said destination buffer means for assembling a packet comprising a number of fields including:

A. an information field including information from said destination buffer means, and

B. a commanding name field including the name of said commanding buffer means,

said destination port means further including means connected to said message assembly means for transmitting the packets generated by said message assembly means over said common bus.

33. A node as defined in claim 32 in which the data processing system includes at least one node generates and transmits packets in response to the receipt of a command including an information field and a commanding name field, said source port means further including means for receiving packets from the common bus and source node directing means connected to said source port means and responsive to the contents of the source name field for directing the contents of the packet to the identified source buffer means.

34. A node as defined in claim 33 wherein said destination message assembly means includes means for generating a plurality of packets to transfer the information in said destination buffer means, each packet generated by said message assembly means further including a last packet field which contains a last packet flag which is set when the packet is the last packet for the message.

35. An interface unit for connection to a host digital computer system and a common bus in a digital data processing system, said host computer including processor unit means and memory means, said interface unit generating packets for transmitting information over said common bus and receiving packets containing information from said common bus and comprising:

A. interface means for connection to said common bus for transmitting packets over and receiving packets from said common bus;

B. storage means connected to said interface means and for connection to said memory means, said storage means containing a plurality of storage locations for storing information from said memory means and for storing packets received by said interface means; and

C. port processor means connected to said interface means and said storage means and for connection to said processor unit means responsive to commands from said processor unit means, said port processor means including;

i. information retrieval means for connection to said memory means and said storage means for enabling information to be transferred from said memory means to said storage means,

ii. message assembly means connected to said storage means for generating a message comprising at least one packet including a plurality of fields including (a) an information field including information from said buffer means, (b) a packet type field containing a packet type that identifies the packet as containing information or as containing a command to be executed and (c) a destination name field identifying the node to receive the packet,

iii. transmission enabling means connected to said message assembly means and said interface means for enabling said interface means to transmit the assembled message over said common bus, and

iv. control means for connection to said processor unit means and connected to said information retrieval means, said message assembly means, and said transmission enabling means for receiving commands from said processor unit means for enabling each said means in response to commands from said processor unit means.

36. An interface unit as defined in claim 35 wherein said interface means transmits packets to the other nodes and receives packets from other nodes over said common bus using a virtual circuit protocol, said port processor means further comprising virtual circuit descriptor table means comprising a plurality of entries each associated with one virtual circuit, each entry including circuit state means identifying the state of the virtual circuit, send sequence number means identifying a sequence number of packets sent over the virtual circuit, receive sequence number means identifying a sequence number of packets received over the virtual circuit, and path status means indicating the operability of the common bus.

37. An interface unit as defined in claim 35 wherein said memory means includes a plurality of buffers each having a name, packets received from said common bus having a name field containing a buffer name, said port processor means further including means responsive to the receipt of a packet for using the contents of the name field of each packet for enabling information in said packet to be transferred to the buffer named in the packet.