Method and structure for automatic SCSI command delivery using the packetized SCSI protocol

• US 6,883,042 B1
• Filed: 04/25/2001
• Issued: 04/19/2005
• Est. Priority Date: 04/25/2001
• Status: Expired due to Term

• Current Assignee: RPX Corporation
• Original Assignee: Adaptec Incorporated (Steel Partners Holdings LP)
• Inventors: Young, B. Arlen
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): FAROOQ, MOHAMMAD O
• Application Number:
  US09/842,750
• Time in Patent Office: 1,455 Days
• Field of Search: 710/4, 710/36, 710/57, 710/107, 710/313
• US Class Current: 710/30
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices

Abstract

A SCSI initiator system includes a Packetized SCSI Protocol hardware packet engine that automatically transmits Packetized SCSI protocol command blocks to a SCSI target with substantially zero latency between the transmission of adjacent command blocks. The packet engine operates independently of any other hardware circuits in the SCSI initiator that are capable of command management. The SCSI initiator system includes a target execution queue containing at least one hardware I/O control block for a SCSI target. The target execution queue is stored in a memory. The system also includes a Packetized SCSI Protocol hardware packet engine coupled to the target execution queue. The Packetized SCSI Protocol hardware packet engine generates Packetized SCSI Protocol packets using information in the at least one hardware I/O control block directly.

Claims

1. A method for transmitting Packetized SCSI Protocol command blocks comprising:

transmitting a first Packetized SCSI Protocol command block comprising;

transmitting at least one byte in said first Packetized SCSI Protocol command block directly from a storage location of said at least one byte wherein said storage location of said at leant one byte is within a stored first hardware I/O control block; and

transmitting a second Packetized SCSI Protocol command block with a substantially zero latency following transmission of said first Packetized SCSI Protocol command block wherein said stored first hardware I/O control block includes a pointer to a storage location of a second hardware I/O control block, and further wherein said second hardware I/O control block includes information used directly in said transmitting said second Packetized SCSI Protocol command block.

2. The method of claim 1 wherein said at least one byte is in a logical unit number field of said first Packetized SCSI protocol command block.

3. A SCSI initiator system comprising:

a target execution queue containing at least two hardware I/O control blocks for a SCSI target wherein the target execution queue is stored in a memory; and

a Packetized SCSI Protocol hardware packet engine coupled to the target execution queue, wherein the Packetized SCSI Protocol hardware packet engine transmits a Packetized SCSI Protocol command block for each hardware I/O control block in said target execution queue with substantially zero latency between transmission of adjacent Packetized SCSI Protocol command blocks.

4. The SCSI initiator system of claim 3 wherein the Packetized SCSI protocol hardware packet engine further comprise:

a hardware information unit transfer controller having a start input line and a data out phase input line wherein the hardware information unit transfer controller sequences hardware generation of the Packetized SCSI Protocol command blocks upon receiving an active signal on the start input line and an active signal on the data out phase input line.

5. The SCSI initiator system of claim 4 wherein the Packetized SCSI protocol hardware packet engine further comprises:

a hardware header generator coupled to the hardware information unit transfer controller, wherein the hardware header generator generates fields in a command L_Q information unit in response to signals from the hardware information unit transfer controller.

6. The SCSI initiator system of claim 5 wherein the Packetized SCSI protocol hardware packet engine further comprises:

a hardware body generator coupled to the hardware information unit transfer controller, wherein the hardware body generator generates fields in a command information unit in response to signals from the hardware information unit transfer controller.

7. The SCSI initiator system of claim 6 further comprising a hardware I/O control block pointer register coupled to the hardware header generator.

8. The SCSI initiator system of claim 7 wherein the hardware I/O control block pointer register is also coupled to the hardware body generator.

9. The SCSI initiator system of claim 5 further comprising a hardware I/O control block pointer register coupled to the hardware header generator.

10. The SCSI initiator system of claim 4 wherein the Packetized SCSI protocol hardware packet engine further comprises:

a hardware body generator coupled to the hardware information unit transfer controller, wherein the hardware body generator generates fields in a command information unit in response to signals from the hardware information unit transfer controller.

11. The SCSI initiator system of claim 10 further comprising a hardware I/O control block pointer register coupled to the hardware body generator.