US4387425A — Masterless and contentionless computer network

Claim 1

Independent Claim 369 words

A computer network comprising: a. a network transmission bus means, and b. a plurality of spatially separated computer stations connected to said network transmission bus means, each of said computer stations being capable of either acting as an independent work station or transmitting information to any one or more of said other computer stations over said network transmission bus means or receiving information from any one or more of said other computer stations over said network transmission bus means, each computer station including: 1. a computer, and ii. an adapter unit, each adapter unit serving to interface its computer to said network transmission bus means, said adapter units collectively controlling access to said network transmission bus means by said computer stations, each adapter unit including a controller for controlling the operations of said adapter unit, said controller including a timer for measuring time and generating signals at the expiration of first and second preselected time intervals, a line activity indicator for monitoring said bus for activity and for sending signals indicating the presence or absence of activity to the controller, control means in said controller responsive to said signal indicating the absence of activity over said first time interval for sending a first control signal to a pulsing device, said pulsing device coupled to said bus and operative for sending a first pulse over said bus on receival of said first control signal from said controller, said first pulse having a length at least equal to the largest distance between any two adapter units, said control means in said controller responsive to said signal indicating the absence of activity over said second time interval unique to said adapter unit for sending a second control signal to said pulsing device, said pulsing device responsive to said second signal to send a second pulse over said bus, c. whereby, the second pulse transmitted by the first adapter unit detecting the absence of activity over said second time interval causes each other adapter unit to detect activity before the expiration of its second time interval and wherein said first adapter unit will be in a unique state relative to the other adapter units for the purpose of assuming control over the bus.

Claim 2

Dependent Claim 369 words

A computer network comprising: a. a network transmission bus means, and b. a plurality of spatially separated computer stations connected to said network transmission bus means, each of said computer stations being capable of either acting as an independent work station or transmitting information to any one or more of said other computer stations over said network transmission bus means or receiving information from any one or more of said other computer stations over said network transmission bus means, each computer station including: 1. a computer, and ii. an adapter unit, each adapter unit serving to interface its computer to said network transmission bus means, said adapter units collectively controlling access to said network transmission bus means by said computer stations, each adapter unit including a controller for controlling the operations of said adapter unit, said controller including a timer for measuring time and generating signals at the expiration of first and second preselected time intervals, a line activity indicator for monitoring said bus for activity and for sending signals indicating the presence or absence of activity to the controller, control means in said controller responsive to said signal indicating the absence of activity over said first time interval for sending a first control signal to a pulsing device, said pulsing device coupled to said bus and operative for sending a first pulse over said bus on receival of said first control signal from said controller, said first pulse having a length at least equal to the largest distance between any two adapter units, said control means in said controller responsive to said signal indicating the absence of activity over said second time interval unique to said adapter unit for sending a second control signal to said pulsing device, said pulsing device responsive to said second signal to send a second pulse over said bus, c. whereby, the second pulse transmitted by the first adapter unit detecting the absence of activity over said second time interval causes each other adapter unit to detect activity before the expiration of its second time interval and wherein said first adapter unit will be in a unique state relative to the other adapter units for the purpose of assuming control over the bus.

Claim 3

Dependent Claim 18 words

The computer network of claim 1 and wherein said network transmission bus means comprises a single bi-directional bus.

Claim 4

Dependent Claim 47 words

The computer network of claim 1 and wherein said adapter unit further includes: a. an address store coupled to said controller for holding a unique number assigned to the adapter unit, and b. a control store coupled to said controller for holding the instruction for the controller.

Claim 5

Dependent Claim 60 words

The computer network of claim 3 and wherein said adapter unit further includes: a. a write circuit coupled to said controller, b. a driver circuit coupled to the output of the write circuit for converting the signals from said write circuit to analog levels, and c. a receiver circuit for translating the incoming signals from said bus to digital levels.

Claim 6

Dependent Claim 82 words

The computer network of claim 4 and wherein said adapter unit further includes: a digital phase locked loop and data separator for separating data received from said receiver circuit into clock and data signals, said data being in serial form, and b. a read circuit coupled to the output of said digital phase locked loop and data separator for converting serial data received from said digital phase locked loop and data separator into parallel data and sending said data to said controller.

Claim 7

Dependent Claim 40 words

The computer network of claim 5 and wherein said adapter unit further includes: a. a relay circuit for connecting said driver circuit and said receiver circuit to said bus, and b. a switch for opening and closing said relay circuit.

Claim 8

Dependent Claim 37 words

The computer network of claim 6 and wherein said adapter unit further includes an internal bus and wherein said controller, said write circuit, said read circuit and said address store are each connected to said internal bus.

Claim 9

Dependent Claim 13 words

The computer network of claim 7 and wherein said controller is a microcontroller.

Claim 10

Dependent Claim 21 words

The computer network of claim 8 and wherein said pulsing device comprises a switch whose state is operated by said microcontroller.

Claim 11

Dependent Claim 43 words

The computer network of claim 9 and wherein said adapter unit further includes a message detector coupled to the output of said receiver circuit for detecting the presence of a message on said bus and sending a signal indicative thereof to said controller.

Claim 12

Dependent Claim 15 words

The computer network of claim 10 and wherein said line activity indicator comprises a flip-flop.

Claim 13

Dependent Claim 52 words

The computer network of claim 11 and wherein said microcontroller includes a program counter, an instruction decoder, an immediate register, a source decoder, a destination decoder, a comparison circuit, an amend circuit for amending the value in the program counter, a multiplexer, a scratch pad memory, an incrementor and a pulse decoder.

Claim 14

Dependent Claim 44 words

The computer network of claim 12 and wherein said digital phase locked loop comprises a plurality of flip-flops, a counter coupled to one of said flip-flops for counting the number of received serialized bits and a synch stripper for stripping out the synch bit.

Claim 15

Dependent Claim 285 words

An adapter unit for use in interfacing a computer to a computer network bus and controlling access of said computer to said computer network bus along with other equal adapter units connecting other computers to said computer network bus comprising: a. a controller for controlling the operations of said adapter unit, said controller including a timer for measuring time and generating signals at the expiration of first and second preselected time intervals, a line activity indicator for monitoring said bus for activity and for sending signals indicating the presence or absence of activity to the controller, control means in said controller responsive to said signal indicating the absence of activity over said first time interval for sending a first control signal to a pulsing device, said pulsing device coupled to said bus and operative for sending a first pulse over said bus on receival of said first control signal from said controller, said first pulse having a length at least equal to the largest distance between any two adapter units, said control means in said controller responsive to said signal indicating the absence of activity over said second time interval unique to said adapter unit for sending a second control signal to said pulsing device, said pulsing device responsive to said second signal to send a second pulse over said bus, b. whereby, the second pulse transmitted by the first adapter unit detecting the absence of activity over said second time interval causes each other adapter unit to detect activity before the expiration of its second time interval and wherein said first adapter unit will be in a unique state relative to the other adapter units for the purpose of assuming control over the bus.

Claim 16

Dependent Claim 285 words

An adapter unit for use in interfacing a computer to a computer network bus and controlling access of said computer to said computer network bus along with other equal adapter units connecting other computers to said computer network bus comprising: a. a controller for controlling the operations of said adapter unit, said controller including a timer for measuring time and generating signals at the expiration of first and second preselected time intervals, a line activity indicator for monitoring said bus for activity and for sending signals indicating the presence or absence of activity to the controller, control means in said controller responsive to said signal indicating the absence of activity over said first time interval for sending a first control signal to a pulsing device, said pulsing device coupled to said bus and operative for sending a first pulse over said bus on receival of said first control signal from said controller, said first pulse having a length at least equal to the largest distance between any two adapter units, said control means in said controller responsive to said signal indicating the absence of activity over said second time interval unique to said adapter unit for sending a second control signal to said pulsing device, said pulsing device responsive to said second signal to send a second pulse over said bus, b. whereby, the second pulse transmitted by the first adapter unit detecting the absence of activity over said second time interval causes each other adapter unit to detect activity before the expiration of its second time interval and wherein said first adapter unit will be in a unique state relative to the other adapter units for the purpose of assuming control over the bus.

Claim 17

Dependent Claim 43 words

The adapter unit of claim 14 and further including: a. an address store coupled to said controller for holding a unique number assigned to the adapter unit; and b. a control store coupled to said controller for holding the instruction for the controller.

Claim 18

Dependent Claim 56 words

The adapter unit of claim 15 and further including: a. a write circuit coupled to said controller, b. a driver circuit coupled to the output of the write circuit for converting the signals from said write circuit to analog levels, and c. a receiver circuit for translating the incoming signals from said bus to digital levels.

Claim 19

Dependent Claim 68 words

The adapter unit of claim 16 and further including: a. a digital phase locked loop and data separator for separating data received from said receiver circuit into clock and data signals said data being in serial form, and b. a read circuit coupled to the output of said digital phase locked loop and data separator for converting serial data into parallel data and sending said/data to said controller.

Claim 20

Dependent Claim 36 words

The adapter unit of claim 17 and further including: a. a relay circuit for connecting said driver circuit and said receiver circuit to said bus, and b. a switch for opening and closing said relay circuit.

Claim 21

Dependent Claim 33 words

The adapter unit of claim 18 and further includes an internal bus and wherein said controller, said write circuit, and read circuit and said address store are each connected to said internal bus.

Claim 22

Dependent Claim 13 words

The adapter unit of claim 19 and wherein said controller is a microcontroller.

Claim 23

Dependent Claim 21 words

The adapter unit of claim 20 and wherein said pulsing device comprises a switch whose state is operated by said microcontroller.

Claim 24

Dependent Claim 43 words

The adapter unit of claim 21 and wherein said adapter unit further includes a message detector coupled to the output of said receiver circuit for detecting the presence of a message on said bus and sending a signal indicative thereof to said controller.

Claim 25

Dependent Claim 15 words

The adapter unit of claim 22 and wherein said line activity indicator comprises a flip-flop.

Claim 26

Dependent Claim 52 words

The adapter unit of claim 23 and wherein said microcontroller includes a program counter, an instruction decoder, an immediate register, a source decoder, a destination decoder, a comparison circuit, an amend circuit for amending the value in the program counter, a multiplexer, a scratch pad memory, an incrementor and a pulse decoder.

Claim 27

Dependent Claim 44 words

The adapter unit of claim 24 and wherein said digital phase locked loop comprises a plurality of flip-flops, a counter coupled to one of said flip-flops for counting the number of received serialized bits and a synch stripper for stripping out the synch bit.

Claim 28

Independent Claim 198 words

A method of placing one out of a plurality of computer stations which are connected to a common network bus and which are equal in the ability to control the bus in a unique state relative to said other computer stations for the purpose of assuming control over said bus comprising: a. assigning each computer station a unique number, b. having each computer station monitor said bus for activity, c. having each computer station that does not detect activity for a predetermined time interval to transmit a first pulse over the bus having a length at least equal to the largest distance between any two computer stations, then d. having each computer station that has transmitted said first pulse to monitor the bus for activity for a time period related to its assigned number, then e. having the first computer station that does not detect activity during its particular time period send a second pulse out over the bus causing all other computer stations to detect activity during their particular time periods, whereby said first computer station will be in a unique state relative to said other computer stations for the purpose of assuming control over said bus.

Claim 29

Independent Claim 198 words

A method of placing one out of a plurality of computer stations which are connected to a common network bus and which are equal in the ability to control the bus in a unique state relative to said other computer stations for the purpose of assuming control over said bus comprising: a. assigning each computer station a unique number, b. having each computer station monitor said bus for activity, c. having each computer station that does not detect activity for a predetermined time interval to transmit a first pulse over the bus having a length at least equal to the largest distance between any two computer stations, then d. having each computer station that has transmitted said first pulse to monitor the bus for activity for a time period related to its assigned number, then e. having the first computer station that does not detect activity during its particular time period send a second pulse out over the bus causing all other computer stations to detect activity during their particular time periods, whereby said first computer station will be in a unique state relative to said other computer stations for the purpose of assuming control over said bus.

Claim 30

Dependent Claim 56 words

The method of claim 26 and wherein the width of the first pulse is at least equal to λ, where λ is equal to 1/v, where 1 is equal to the largest distance between any two computer stations connected to the bus and v is equal to the propogation speed of electric waves over the bus.

Claim 31

Dependent Claim 25 words

The method of claim 27 and wherein each computer station monitors the bus for activity for a time period directly proportional to its assigned number.

Claim 32

Dependent Claim 35 words

The method of claim 28 and wherein the time period for monitoring for activity is greater than Δ×n where Δ is equal to twice λ and n is the assigned number of the adapter unit.

Claim 33

Independent Claim 242 words

A method of enabling a plurality of computer stations connected to a common transmission bus to decide amongst themselves which computer station should assume control over said bus at all times comprising: a. assigning each computer station a unique number, b. having each computer station monitor said bus for activity, c. continually passing control from one live computer station to another in numerical sequence according to its unique number, and d. having said live computer stations conduct an election amongst themselves to determine one live computer station to assume control over the bus in the event passing control ceases for a preselected time interval, said election including: i. having each computer station that does not detect activity over said predetermined time interval T 1 send a first pulse P 1 out over said bus having a length at least equal to the largest distance between any two computer stations, ii. having each computer station that sends a first pulse out over said bus monitor said bus for activity for a unique time period T 2 , and then iii. having the first computer station whose unique time period expires without detecting activity send a second pulse out over the bus said second pulse causing all other computer stations to detect activity during their particular time periods, whereby said first computer station will be in a unique state relative to said other computer stations for the purpose of assuming control over said bus.

Claim 34

Independent Claim 242 words

A method of enabling a plurality of computer stations connected to a common transmission bus to decide amongst themselves which computer station should assume control over said bus at all times comprising: a. assigning each computer station a unique number, b. having each computer station monitor said bus for activity, c. continually passing control from one live computer station to another in numerical sequence according to its unique number, and d. having said live computer stations conduct an election amongst themselves to determine one live computer station to assume control over the bus in the event passing control ceases for a preselected time interval, said election including: i. having each computer station that does not detect activity over said predetermined time interval T 1 send a first pulse P 1 out over said bus having a length at least equal to the largest distance between any two computer stations, ii. having each computer station that sends a first pulse out over said bus monitor said bus for activity for a unique time period T 2 , and then iii. having the first computer station whose unique time period expires without detecting activity send a second pulse out over the bus said second pulse causing all other computer stations to detect activity during their particular time periods, whereby said first computer station will be in a unique state relative to said other computer stations for the purpose of assuming control over said bus.

Claim 35

Dependent Claim 61 words

The method of claim 30 and wherein T 1 >N×Δ; N=the maximum number of computer stations that can be handled by the bus; Δ=2λ; λ=l/v; 1=the largest distance between any two computer stations connected to the bus; v=the propogation speed of electric waves over the bus; P 1 ≧λ; T 2 =N×Δ; and n=the unique assigned number of the computer station.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1986-06-06	1986-12-06	1987-06-07	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1990-06-06	1990-12-06	1991-06-07	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1994-06-06	1994-12-06	1995-06-07	$7700.00	Window Closed / Lapsed

Masterless and contentionless computer network

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