Patent US3860405A successfully refreshed from Google Patents.
Patent US3806885A successfully refreshed from Google Patents.
US3806885A
Expired / Lapsed
US
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Polling mechanism for transferring control from one data processing system or subsystem to another
Assignee: International Business Machines Corp
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Filing: 1972-12-29
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Granted: 1974-04-23
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Expires: 1992-12-29
Abstract
Abstract A polling mechanism for use with apparatus for establishing and maintaining communication between a number of different types of subsystems. The apparatus includes a select line which interconnects all of the units in a closed loop. Control logic is provided at each unit in series with the select line. A bidirectional deselect line is provided interconnecting all of the units. A unit which has the poll (master unit) passes the poll by energizing the select line. A unit which does not wish to obtain the poll and thereby become the master unit, energizes the select line to the next unit in series in response to energization of the select line from the master unit. A unit obtains the poll (and becomes the master unit) by not energizing the select line to a next unit but by energizing the deselect which indicates to all units that the poll has been accepted. A request line is provided interconnecting all of the units so that any unit can indicate that it would like to obtain the poll. The unit which has the poll passes the poll by raising the select line but if it wishes to retain the poll, it need not initiate a poll transfer. To provide for the situation where a unit has an urgent need for the poll, there is an urgent request line which a requesting unit can raise. The unit which has the poll will then pass the poll to the requesting unit provided it also does not have an urgent need for the poll.
Inventors
- 👤 B Moore
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 23:42
CPC Classifications
G; G06; G06F; G06F13/00; G06F13/14; G06F13/36; G06F13/368; G06F13/37
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
133 words
A polling mechanism for selectively establishing communication between ones of a plurality of units including at least a first unit and a second unit forming interconnected data handling systems, comprising: a select line interconnecting said units; control logic at each unit in seriatim with said select line; a deselect line and a polling request line interconnecting said control logic at each of said units in parallel; means in the control logic of said first unit for passing poll control from said first unit to said second unit including means for energizing said select line in response to a signal on said polling request line from a requesting unit; and means in the control logic of said second unit responsive to said select line for accepting said poll control by energizing said deselect line.
Claim 2
Dependent Claim
133 words
A polling mechanism for selectively establishing communication between ones of a plurality of units including at least a first unit and a second unit forming interconnected data handling systems, comprising: a select line interconnecting said units; control logic at each unit in seriatim with said select line; a deselect line and a polling request line interconnecting said control logic at each of said units in parallel; means in the control logic of said first unit for passing poll control from said first unit to said second unit including means for energizing said select line in response to a signal on said polling request line from a requesting unit; and means in the control logic of said second unit responsive to said select line for accepting said poll control by energizing said deselect line.
Claim 3
Dependent Claim
33 words
The combination according to claim 1 further including means in said control logic at a unit for energizing said polling request line upon the condition that said unit wishes to acquire poll control.
Claim 4
Dependent Claim
12 words
raising select out to cause said unit to remain a slave unit.
Claim 5
Dependent Claim
12 words
raising select out to cause said unit to remain a slave unit.
Claim 6
Dependent Claim
76 words
The combination according to claim 1 further including an urgent polling request line interconnecting said units and means in said control logic of said first unit for energizing said urgent polling request line when an urgent condition exists and means in said second unit responsive to energization of said urgent polling request line by said first unit for passing the poll to said first unit provided said urgent condition does not exist in said second unit.
Claim 7
Dependent Claim
137 words
A communication interface in which units attached thereto have the same priority with request to each other including a polling mechanism which is not supervised or controlled by any one unit all of the time, comprising: a select out line at each unit; a select in line at each unit; means connecting the select out line of one unit to the select in line of the next unit and the select out line from the last unit to the select in line oF the first unit; a deselect line interconnecting all said units in parallel; and interface logic means at one unit for selectively either energizing said select out line to thereby pass the poll from said one unit to the next unit or energizing said deselect line to thereby accept the poll from a previous unit.
Claim 8
Dependent Claim
137 words
A communication interface in which units attached thereto have the same priority with request to each other including a polling mechanism which is not supervised or controlled by any one unit all of the time, comprising: a select out line at each unit; a select in line at each unit; means connecting the select out line of one unit to the select in line of the next unit and the select out line from the last unit to the select in line oF the first unit; a deselect line interconnecting all said units in parallel; and interface logic means at one unit for selectively either energizing said select out line to thereby pass the poll from said one unit to the next unit or energizing said deselect line to thereby accept the poll from a previous unit.
Claim 9
Dependent Claim
93 words
A communication mechanism for establishing communication between one subsystem and another subsystem in a data handling system comprised of a plurality of subsystems which comprises: control logic in each subsystem; a select in input to said logic; a select out output from said logic; a deselect output from said logic; means interconnecting said deselect output of said units; means for connecting in series said select lines by connecting select out to select in of the next successive unit; means in said control logic responsive to energization of said select in line for selectively:
Claim 10
Dependent Claim
93 words
A communication mechanism for establishing communication between one subsystem and another subsystem in a data handling system comprised of a plurality of subsystems which comprises: control logic in each subsystem; a select in input to said logic; a select out output from said logic; a deselect output from said logic; means interconnecting said deselect output of said units; means for connecting in series said select lines by connecting select out to select in of the next successive unit; means in said control logic responsive to energization of said select in line for selectively:
Claim 11
Dependent Claim
66 words
The combination according to claim 5 further including a poll request line from said logic, means interconnecting said poll request lines of said units, means in said logic for energizing said poll request line to request the poll from another of said units and, means in said logic responsive to said poll request line to pass the poll to a requesting unit by raising select out.
Claim 12
Dependent Claim
85 words
The combination according to claim 6 further including an urgent polling request line from said logic, means interconnecting said urgent polling request lines of said units and means in said logic for energizing said urgent polling request line in response to an urgent condition at said unit and means in said logic responsive to energization of said urgent polling request line to pass the poll to the requesting unit by raising select out provided that an urgent condition does not exist in the passing unit.
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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) | 1977-04-22 | 1977-10-22 | 1978-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-22 | 1981-10-22 | 1982-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-22 | 1985-10-22 | 1986-04-23 | $7700.00 | Window Closed / Lapsed |