System for assigning and identifying devices on bus within predetermined period of time without requiring host to do the assignment

• US 5,544,333 A
• Filed: 01/30/1995
• Issued: 08/06/1996
• Est. Priority Date: 05/14/1993
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Tsao, Gary Y., Frazier, Giles R.
• Primary Examiner(s): Lim, Krisna
• Application Number:
  US08/380,473
• Time in Patent Office: 554 Days
• Field of Search: 395/304
• US Class Current: 710/124
• CPC Class Codes: G06F 12/0669 with decentralised address assignment
• CPC Class Codes: G06F 15/177 Initialisation or configuration control processor initialisation G06F9/4405
• CPC Class Codes: G06F 9/4411 Configuring for operating with peripheral devices; Loading of device drivers

Abstract

In a computer system having multiple devices on a bus, a method for a first device on the bus to designate its own identifier including the steps of the first device transmitting on the bus a request for a device with a desired identifier to respond, determining that no device on the bus responds to the request, and upon such determination, designating the desired identifier to identify the first device to at least one of the multiple devices on the bus. In addition, in a computer system having multiple devices on a bus, a first device including apparatus for transmitting on the bus a request for a device with a desired identifier to respond, apparatus for determining that no device on the bus responds to the request, and apparatus for, upon such determination, designating the desired identifier to identify at least one of the first device to the multiple devices on the bus.

Claims

1. In a computer system having a plurality of devices on a bus, a method for a first device on the bus to designate its own identifier on the bus comprising the steps of:

first determining that no device on the bus with a desired identifier is requested by any other device on the bus over a predetermined period of time;

upon such first determination, said first device transmitting on the bus a request for a device with the desired identifier to respond;

secondly determining that no device on the bus responds to the request; and

upon such second determination, the first device designating the desired identifier to identify the first device on the bus to at least one of the plurality of devices on the bus other than the first device.

2. The method of claim 1 wherein the step of secondly determining includes waiting a predetermined amount of time for any device to respond to the request.

3. The method of claim 2 wherein the step of requesting includes utilizing a second identifier to identify the first device on the bus during the transmitted request.

4. The method of claim 1 wherein the desired identifier is initially the same for all devices seeking an identifier on the bus.

5. The method of claim 4 further comprising a step of notifying at least one other device of the designated identifier of the first device.

18. The method of claim 1 wherein the predetermined period of time is randomly generated by the first device.

6. In a computer system having a plurality of devices on a bus, a first device comprising:

means for first determining that no device on the bus with a desired identifier is requested by any other device on the bus over a predetermined period of time;

means for, upon such first determination, transmitting on the bus a request for a device with the desired identifier to respond;

means for secondly determining that no device on the bus responds to the request; and

means for, upon such second determination, the first device designating the desired identifier to identify the first device on the bus to at least one of the plurality of devices on the bus other than the first device.

7. The first device of claim 6 wherein the means for secondly determining includes means for waiting a predetermined amount of time for any device to respond to the request.

8. The first device of claim 7 wherein the means for requesting includes means for utilizing a second identifier to identify the first device on the bus during the transmitted request.

9. The first device of claim 6 wherein the desired identifier is initially the same for all devices seeking an identifier on the bus.

10. The first device of claim 9 further comprising means for notifying at least one other device of the designated identifier of the first device.

11. The first device of claim 10 wherein the desired identifier is initially the same for all devices seeking an identifier on the bus.

12. The first device of claim 11 further comprising means for notifying at least one other device of the designated identifier of the first device.

13. The computer system of claim 6 wherein the predetermined period of time is randomly generated by the first device.

14. A data processing system comprising:

a plurality of devices on a bus, said plurality of devices including a first device, said first device including;

means for first determining that no device on the bus with a desired identifier is requested by any other device on the bus over a predetermined period of time;

means for, upon such first determination, transmitting on the bus a request for a device with the desired identifier to respond;

means for secondly determining that no device on the bus responds to the request; and

means for upon such second determination, the first device designating the desired identifier to identify the first device on the bus to at least one of the plurality of devices on the bus other than the first device.

15. The first device of claim 14 wherein the means for second determining includes means for waiting a predetermined amount of time for any device to respond to the request.

16. The first device of claim 15 wherein the means for requesting includes means for utilizing a second identifier to identify the first device on the bus during the transmitted request.

17. The data processing system of claim 14 wherein the predetermined period of time is randomly generated by the first device.