Method and apparatus for a fibre channel control unit to execute search commands locally

• US 6,687,766 B1
• Filed: 01/12/2000
• Issued: 02/03/2004
• Est. Priority Date: 10/14/1998
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Dugan, Robert J., Huang, Catherine C., Flanagan, John R., Ricci, Louis W., Casper, Daniel F.
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): ELAMIN, ABDELMONIEM I
• Application Number:
  US09/481,715
• Time in Patent Office: 1,483 Days
• Field of Search: 710/20, 710/21, 710/29, 714/720
• US Class Current: 710/20
• CPC Class Codes: G06F 13/122 where hardware performs an I/O function other than control of data transfer

Abstract

The present invention provides a method for fibre channel control units to execute commands locally when a channel sends a repeat execute indicator in conjunction with certain other field settings, wherein the control unit will repeat and chain control words until certain predefined conditions occur.

Claims

1. A method for fibre channel control units to repeat successful execution of a first control word in a command chain after receiving said first control word in a first header of a first information unit from a fibre channel link, the method comprising the steps of:

a) receiving said first control word in said first information unit and receiving a second control word in a second information unit from said fibre channel link;

b) repeating the successful execution of said first control word up to a predetermined number of times if a first condition is met;

c) receiving a second control word in a second information unit from said fibre channel link;

d) chaining to execute said second control word if a second condition is met; and

,

e) sending status to said fibre channel link after said repeating and said chaining are complete.

2. The method according to claim 1 wherein said predetermined number of times is 128.

3. The method according to claim 1 wherein said first condition comprises a Channel-end status set to the on state and a Device-end status set to the on state and a status modifier set to the off state.

4. The method according to claim 3 wherein said first header in said first information unit includes a chain command field being set to the on state and a chain data field being set to the off state.

5. The method according to claim 1 wherein said first conditions are terminated by a cancel or reset command.

6. The method according to claim 1 wherein said second condition includes channel-end status and device-end status and status modifier status being set to the on state.

7. The method according to claim 6 wherein said second condition utilizes a status field with bits 1, 4 and 5 set to one of byte 1 of word one.

8. The method according to claim 6 wherein said second condition utilizes a status field with bits 0, 2, 3, 6 and 7 set to zero of byte 1 of word one.

9. A method for a fibre channel to enable a control unit to repeat successful execution of control words and chain control words comprising the steps of:

a) marking a first information unit containing a first control word with a repeat execute flag, permitting repeated successful execution of said first control word;

b) transmitting said first information unit to a fibre channel link;

c) transmitting a second information unit of a second control word to said fibre channel link;

d) chaining to execute said second control word if a second condition is met; and

e) sending status to said fibre channel link after said repeating and said chaining are complete.

10. The method according to claim 9 wherein said first information unit includes a chain command field being set to one and a chain data field being set to zero.

11. The method according to claim 9 further comprising the step of receiving said first information unit and said second information unit at said control unit.

12. The method according to claim 9 wherein said control unit executes said first control word of first information unit two or more times before executing said second control word.

13. An apparatus for fibre channel control units to repeat successful execution of a first control word in a command chain after receiving said first control word in a first header of a first information unit from a fibre channel link said apparatus comprising:

a) a receiver receiving said first control word in said first information unit and receiving a second control word in a second information unit from said fibre channel link;

b) a repeater repeating the successful execution of said first control word up to a predetermined number of times if a first condition is met;

c) a chainer chaining to execute said second control word if a second condition is met; and

,

d) a sender sending status to said fibre channel link after said repeating and said chaining are complete.

14. The apparatus according to claim 13 wherein said predetermined number of times is 128.

15. The apparatus according to claim 13 wherein said first condition comprises a Channel-end status set to the on state and a Device-end status set to the on state and a status modifier set to the off state.

16. The apparatus according to claim 15 wherein said first header in said first information unit includes a chain command field being set to the on state and a chain data field being set to the off state.

17. The apparatus according to claim 13 wherein said first conditions are terminated by a cancel or reset command.

18. The apparatus according to claim 13 wherein said second condition includes channel-end status and device-end status and status modifier status being set to the on state.

19. The apparatus according to claim 18 wherein said second condition utilizes a status field with bits 1, 4 and 5 set to one of byte 1 of word one.

20. The apparatus according to claim 18 wherein said second condition utilizes a status field with bits 0, 2, 3, 6 and 7 set to zero of byte 1 of word one.

21. An apparatus for a fibre channel to enable a control unit to repeat successful execution of control words and chain control words said apparatus comprising:

a) an initiator marking a first information unit containing a first control word with a repeat execute flag, permitting repeated successful execution of said first control word; and

,

b) a transmitter transmitting said first information unit and a second information unit to a fibre channel link;

c) a transmitter transmitting a second information unit of a second control word to said fibre channel links;

d) chaining to execute said second control word if a second condition is met; and

e) sending status to said fibre channel link after said repeating and said chaining are complete.

22. The apparatus according to claim 21 wherein said first information unit includes a chain command field being set to one and a chain data field being set to zero.

23. The apparatus according to claim 21 further comprising a receiver receiving said first information unit and said second information unit at said control unit.

24. The apparatus according to claim 21 wherein said control unit executes said first control word of first information unit two or more times before executing said second control word.