Patent US4885578A successfully refreshed from Google Patents.
US4885578A
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US
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In band connection establishment for a multiple multi-drop network
Assignee: International Business Machines Corp
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Filing: 1986-12-12
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Granted: 1989-12-05
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Expires: 2006-12-12
Abstract
Abstract A system for establishing connections between processors in a distributed system of processors connected by a multiple multi-drop network. No wires are needed in addition to those already present in an existing network. In such a network connecting n processors, each processor is connected to all others by n identical multi-drop links. Links are assigned to processors on a one-to-one basis and a processor may transmit messages only on its assigned link. Processors may receive messages on any of these links, thereby enabling a processor to communicate with all others. The advantage of such a network over a single multi-drop link is that there is no contention for a shared link since each processor has a unique transmit line. In addition, no central control means is required for the network, as completely distributed control is utilized.
Inventors
- 👤 Kenneth J. Perry
- 👤 Yannick J. Thefaine
- 👤 Brent T. Hailpern
- 👤 Lee W. Hoevel
- 👤 Dennis G. Shea
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:10
CPC Classifications
G; G06; G06F; G06F15/00; G06F15/76; G06F15/80; G06F15/8007; G06F15/8015; G06F15/16; G06F15/163; G06F15/173
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
202 words
A method of establishing communication between n processors connected by n multi-drop links; where n is an integer, said method comprising the steps of: assigning each one of said n processors a different predetermined one of said n multi-drop links as a contention free transmit link; assigning each one of said n processors a different unique calling code; transmitting by a first one of said n processors on its assigned transmit link the unique calling code of a second one of said n processors with which said first one of said n processors wants to establish a connection for communication purposes; checking, in a round robin search order, all links other than its own transmit link, by said second one of said n processors to determine if it is receiving its own calling code on the assigned transmit link of anaother one of said n processors; and establishing a connection between said first and second one of said n processors in response to said second one of said n processors determining that said first one of said n processors is transmitting said second one of said n processors unique calling code on said first one of said n processors assigned transmit link.
Claim 2
Independent Claim
202 words
A method of establishing communication between n processors connected by n multi-drop links; where n is an integer, said method comprising the steps of: assigning each one of said n processors a different predetermined one of said n multi-drop links as a contention free transmit link; assigning each one of said n processors a different unique calling code; transmitting by a first one of said n processors on its assigned transmit link the unique calling code of a second one of said n processors with which said first one of said n processors wants to establish a connection for communication purposes; checking, in a round robin search order, all links other than its own transmit link, by said second one of said n processors to determine if it is receiving its own calling code on the assigned transmit link of anaother one of said n processors; and establishing a connection between said first and second one of said n processors in response to said second one of said n processors determining that said first one of said n processors is transmitting said second one of said n processors unique calling code on said first one of said n processors assigned transmit link.
Claim 3
Dependent Claim
28 words
The method of claim 1, wherein said step of establishing a connection is completed after determining that said second one of said n processors is not already busy.
Claim 4
Independent Claim
291 words
A method of establishing connections between processors I and J in a distributed system of n processors connected by n identical multi-drop links, where n is an integer, with each of said n processors being assigned a predetermined one of said n multi-drop links as a contention free transmit link and all other links being receive links, said method comprising the steps of: (1) assigning each processor I of said n processors a unique calling code, termed "calling Code I", which distinguishes each one of said n processors from another; (2) starting a processor idle routine, termed "Processor Idle Routine J", for each processor J of said n processors, said "Processors Idle Routine J" including the step of: (a) checking each of the transmit links of the other ones of said n processors for the presence of a signal termed "Calling Code J", which is indicative of the processor assigned that transmit link desiring to be connected to processor J; (3) starting an "establish a connection between a processor I and a processor J routine: said" establish a connection routine"including the steps of: (a) putting "Calling Code J" on processor I's transmit line, which is indicative of processor I desiring to be connected to processor J; (b) checking the transmit link of processor J by processor I to determine if a signal "processor I calling me" is present, which is indicative of processor J receiving the "Calling Code -- J: signal" signal from processor I; (c) acknowledging the presence of said "processor I calling me" signal by processor I, by placing a signal "Yes, J Called" on processor I's transmit link; and (d) establishing a connection between processor I and processor J in response to the acknowledgement of step 3 (c).
Claim 5
Independent Claim
291 words
A method of establishing connections between processors I and J in a distributed system of n processors connected by n identical multi-drop links, where n is an integer, with each of said n processors being assigned a predetermined one of said n multi-drop links as a contention free transmit link and all other links being receive links, said method comprising the steps of: (1) assigning each processor I of said n processors a unique calling code, termed "calling Code I", which distinguishes each one of said n processors from another; (2) starting a processor idle routine, termed "Processor Idle Routine J", for each processor J of said n processors, said "Processors Idle Routine J" including the step of: (a) checking each of the transmit links of the other ones of said n processors for the presence of a signal termed "Calling Code J", which is indicative of the processor assigned that transmit link desiring to be connected to processor J; (3) starting an "establish a connection between a processor I and a processor J routine: said" establish a connection routine"including the steps of: (a) putting "Calling Code J" on processor I's transmit line, which is indicative of processor I desiring to be connected to processor J; (b) checking the transmit link of processor J by processor I to determine if a signal "processor I calling me" is present, which is indicative of processor J receiving the "Calling Code -- J: signal" signal from processor I; (c) acknowledging the presence of said "processor I calling me" signal by processor I, by placing a signal "Yes, J Called" on processor I's transmit link; and (d) establishing a connection between processor I and processor J in response to the acknowledgement of step 3 (c).
Claim 6
Independent Claim
225 words
A method of establishing communication between n processors connected by n multi-drop links, where n is an integer, said method comprising the steps of: assigning each one of said n processors a different predetermined one of said n multi-drop links as a contention free transmit link; assigning each one of said n processors a different unique calling code; transmitting by a first one of said n processors on its assigned transmit link the unique calling code of a second one of said n processors with which said first one of said n processors wants to establish a connection for communication purposes: checking all links other than its own transmit link, by said second one of said n processors to determine if it is receiving its own calling code on the assigned transmit link of another one of said n processors; determining that said second one of said n processors is not already busy; and establishing a connection between said first and second one of said n processors following the determination that said second one of said n processors is not already busy, and in response to said second one of said n processors determining that said first one of said n processors is transmitting said second one of said n processors unique calling code on said first one of said n processors assigned transmit link.
Claim 7
Independent Claim
225 words
A method of establishing communication between n processors connected by n multi-drop links, where n is an integer, said method comprising the steps of: assigning each one of said n processors a different predetermined one of said n multi-drop links as a contention free transmit link; assigning each one of said n processors a different unique calling code; transmitting by a first one of said n processors on its assigned transmit link the unique calling code of a second one of said n processors with which said first one of said n processors wants to establish a connection for communication purposes: checking all links other than its own transmit link, by said second one of said n processors to determine if it is receiving its own calling code on the assigned transmit link of another one of said n processors; determining that said second one of said n processors is not already busy; and establishing a connection between said first and second one of said n processors following the determination that said second one of said n processors is not already busy, and in response to said second one of said n processors determining that said first one of said n processors is transmitting said second one of said n processors unique calling code on said first one of said n processors assigned transmit link.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-04 | 1993-06-05 | 1993-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-04 | 1997-06-05 | 1997-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-04 | 2001-06-05 | 2001-12-05 | $7700.00 | Window Closed / Lapsed |