Patent US2655164A successfully refreshed from Google Patents.
US5481675A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Asynchronous serial communication system for delaying with software dwell time a receiving computer's acknowledgement in order for the transmitting computer to see the acknowledgement
Assignee: International Business Machines Corp
•
Filing: 1992-05-12
•
Granted: 1996-01-02
•
Expires: 2012-05-12
Abstract
Abstract A software asynchronous communication protocol between two computers allows the roles of master and slave to be switched between the computers, depending on the nature and direction of the communication. In order to avoid truncating bit strings transmitted between the computers due to a difference in the write/read cycles of the computers, the software incorporates a dwell to accommodate the slowest computer in the system.
Inventors
- 👤 Chris T. Kapogiannis
- 👤 John F. Harmuth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 05:03
CPC Classifications
G; G06; G06F; G06F15/00; G06F15/16; G06F15/163; G06F15/17; H; H04; H04L; H04L12/00; H04L12/28; H04L12/40; H04L12/40143; H04L69/00; H04L69/14; H04L69/26; H04L9/00; H04L9/40; H04L67/00; H04L67/01; H04L67/12
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
152 words
A method of asynchronous full-duplex communications between two or more computers connected via separate serial communications links comprising the steps of: measuring relative READ/WRITE cycle times for each of said computers by transmitting over a serial channel from a first computer to a second computer a data string and responding by the second computer with an acknowledgement over said serial channel and determining whether the first computer sees the acknowledgement and repeating the process by transmitting a dam string from the second computer to the first computer over said serial channel and responding by the first computer with an acknowledgement over said serial channel; and adding a delay in the form of a software dwell time in a time period between receiving a data string and responding with an acknowledgement as necessary to allow said computers to see the acknowledgements from computers to which data strings were transmitted over said serial channel.
Claim 2
Independent Claim
152 words
A method of asynchronous full-duplex communications between two or more computers connected via separate serial communications links comprising the steps of: measuring relative READ/WRITE cycle times for each of said computers by transmitting over a serial channel from a first computer to a second computer a data string and responding by the second computer with an acknowledgement over said serial channel and determining whether the first computer sees the acknowledgement and repeating the process by transmitting a dam string from the second computer to the first computer over said serial channel and responding by the first computer with an acknowledgement over said serial channel; and adding a delay in the form of a software dwell time in a time period between receiving a data string and responding with an acknowledgement as necessary to allow said computers to see the acknowledgements from computers to which data strings were transmitted over said serial channel.
Claim 3
Dependent Claim
95 words
The asynchronous communication method recited in claim 1 further comprising the steps of: initiating by said first computer, acting as a master, a first communication to a second computer by transmitting a data string to said second computer, acting as a slave; returning by said second computer an acknowledgement to said first computer; asynchronously initiating by said second computer, acting as a master, a second communication to said first computer by transmitting a data string to the first computer, acting as a slave; and returning by said first computer an acknowledgement to said second computer.
Claim 4
Dependent Claim
39 words
The asynchronous communication method recited in claim 2 wherein said second computer, in response to said first communication, performs a software dwell if added as a result of said measuring step before returning an acknowledgement to said first computer.
Claim 5
Dependent Claim
39 words
The asynchronous communication method recited in claim 2 wherein said first computer, in response to said second communication, performs a software dwell if added as a result of said measuring step before returning an acknowledgement to said second computer.
Claim 6
Dependent Claim
42 words
The asynchronous communication method as recited in claim 2 wherein said first communication is a command to perform one or more tasks and said second communication is status communication initiated by said second computer upon completion or failure to complete each task.
Claim 7
Dependent Claim
21 words
The asynchronous communication method recited in claim 1 wherein the step of measuring is performed once upon interconnection of said computers.
Claim 8
Dependent Claim
27 words
The asynchronous communication method recited in claim 6 wherein the step of measuring is performed automatically by each computer polling other computers to which it is connected.
References Cited (Backward Citations)
US3974479A
Cited
US4050096A
Cited
US4330824A
Cited
US4455661A
Cited
US4390969A
Cited
EP0304540A2
Cited
US4476527A
Cited
US4486833A
Cited
US4660169A
Cited
US4710917A
Cited
US4855901A
Cited
US4672570A
Cited
US5125088A
Cited
EP0275135A2
Cited
US5121492A
Cited
US4943907A
Cited
US5151986A
Cited
US5237696A
Cited
US5040109A
Cited
US5237670A
Cited
EP0386935A2
Cited
US4891709A
Cited
US5060239A
Cited
US5070443A
Cited
US5220659A
Cited
US5388250A
Cited
US5313621A
Cited
US5301307A
Cited
US5268906A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-01 | 1999-07-03 | 2000-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-01 | 2003-07-03 | 2004-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-01 | 2007-07-03 | 2008-01-02 | $7700.00 | Window Closed / Lapsed |