1. A component mounting apparatus comprising:
a first transport mechanism that transports a first board in a board transport direction;
a second transport mechanism that is arranged in parallel with the first transport mechanism and transports a second board in the board transport direction;
a first component supply section that is disposed on a lateral side of the first transport mechanism;
a second component supply section that is disposed on a lateral side of the second transport mechanism;
a first mounting head that is configured to pick up a component supplied from the first component supply section and mount the component onto the first board and the second board;
a second mounting head that is configured to pick up a component supplied from the second component supply section and mount the component onto the first board and the second board; and
a control unit that controls the first transport mechanism, the second transport mechanism, the first component supply section, the second component supply section, the first mounting head, and the second mounting head based on mounting data,
wherein each of the first transport mechanism and the second transport mechanism includes an upstream side operation area where an upstream side board holding part for positioning and holding the first board or the second board is provided, and a downstream side operation area where a downstream side board holding part that is provided on a downstream side in the board transport direction with reference to the upstream side operation area for positioning and holding the first board or the second board is provided, and
wherein when the mounting data corresponds to an independent mounting mode in which the first mounting head is used to mount the component only onto the first board and the second mounting head is used to mount the component only onto the second board, the control unit performs a control so that the upstream side operation area is used as a mounting area where a component is mounted onto a board that is positioned and held by the upstream side board holding part, and
when the mounting data corresponds to an alternating mounting mode in which both of the first mounting head and the second mounting head are used to mount the components sequentially onto a board that is first carried into the downstream side operation area among the first board and the second board, the control unit performs a control so that the upstream side operation area is used as a standby area where a board to be carried to the downstream side operation area temporarily waits.
2. The component mounting apparatus according to claim 1, wherein when the mounting data corresponds to the alternating mounting mode, and when the first board or the second board is not present as a component mounting target in one transport mechanism among the first transport mechanism and the second transport mechanism, the control unit performs a control so that the upstream side operation area of the other transport mechanism is used as the mounting area.
3. A component mounting method for mounting a component onto a board by a component mounting apparatus that includes a first transport mechanism that transports a first board in a board transport direction, a second transport mechanism that is arranged in parallel with the first transport mechanism and transports a second board in the board transport direction, a first component supply section that is disposed on a lateral side of the first transport mechanism, a second component supply section that is disposed on a lateral side of the second transport mechanism, a first mounting head that is configured to pick up a component supplied from the first component supply section and mount the component onto the first board and the second board, and a second mounting head that is configured to pick up a component supplied from the second component supply section and mount the component onto the first board and the second board, and controls the first transport mechanism, the second transport mechanism, the first component supply section, the second component supply section, the first mounting head, and the second mounting head based on mounting data, wherein each of the first transport mechanism and the second transport mechanism includes an upstream side operation area where an upstream side board holding part for positioning and holding the first board or the second board is provided, and a downstream side operation area where a downstream side board holding part that is provided on a downstream side in the board transport direction with reference to the upstream side operation area for positioning and holding the first board or the second board is provided,
the method comprising:
determining whether the mounting data corresponds to an independent mounting mode for executing independent mounting in which the first mounting head is used to mount the component only onto the first board and the second mounting head is used to mount the component only onto the second board, or an alternating mounting mode for executing alternating mounting in which both of the first mounting head and the second mounting head are used to mount the components sequentially onto a board that is first carried into the downstream side operation area among the first board and the second board,
executing the independent mounting using the upstream side operation area as a mounting area where a component is mounted onto a board that is positioned and held by the upstream side board holding part when it is determined that the mounting data corresponds to the independent mounting mode; and
executing the alternating mounting using the upstream side operation area as a standby area where a board carried to the downstream side operation area temporarily waits when it is determined that the mounting data corresponds to the alternating mounting mode.
4. The component mounting method according to claim 3, further comprising:
executing, when it is determined that the mounting data corresponds to the alternating mounting mode, and when the first board or the second board is not present as a component mounting target in one transport mechanism among the first transport mechanism and the second transport mechanism, the alternating mounting using the upstream side operation area of the other transport mechanism as the mounting area.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for achieving agreement among n participating network devices to an agree-value in a network, the agreement arising out of a series of messages being sent and received by each participating network device, whereby the number t of faulty devices is less than n3, each participating network device performing the following steps:
a) broadcasting to the participating network devices an init-vote message comprising an init-vote value;
b) once having received one of n valid of the init-vote messages with init-vote values from the participating network devices and a signal from a failure detector,
evaluating the received init-vote values to obtain a verification-vote value whereby the verification-vote value is an evaluating function of the received init-vote values;
c) broadcasting to the participating network devices a verification-vote message comprising the obtained verification-vote value; and
d) once having received n of the verification-vote messages comprising the same verification-vote value,
deciding the agree-value to be equal to the same verification-vote value, or having received a signal from any failure detector;
e) broadcasting to the participating network devices a signed verification-vote message comprising the obtained verification-vote value and a signature; and
f) once having received n-t signed verification-vote messages, performing a fallback agreement protocol with an initial value that has the simple majority of the received obtained verification-vote values.
2. A method for achieving agreement among n participating network devices to an agree-value in a network, the agreement arising out of a series of messages being sent and received by each participating network device, whereby the number t of faulty devices is less than n3, each participating network device performing the following steps:
i) performing for a number of honest participating network devices that exceeds 2n3 an agreement protocol that comprises failure detection;
ii) performing a validation protocol, using detector means that validates whether agreement is reached; and
iii) deciding for the agree-value in the case that at least x of the participating network devices agree, where x is a number larger than t, or
performing a fallback agreement protocol if at least one participating network device suspects that the agreement is not reached, the fallback agreement protocol producing the same agree-value value if at least one of the honest participating network devices has already decided for the agree-value.
3. Method according to claim 1, whereby the evaluating function is the simple majority.
4. Method according to claim 1, whereby the initial value for the fallback agreement protocol is obtained by a transition function that outputs the absolute majority of the received obtained verification-vote values if such absolute majority exists.
5. Method according to claim 1, whereby the initial value is only accepted if the participating network device proves by including the signature that its initial value belongs to the simple majority or is obtained from the transition function.
6. Method according to claim 4, whereby the initial value is only accepted if the participating network device proves by including the signature that its initial value belongs to the simple majority or is obtained from the transition function.
7. Method according to claim 1, whereby the signature (s) is replaced by a broadcast primitive which guarantees that all the participating network devices receive a sent message or none of them.
8. Method according to claim 1, whereby the network is a partially synchronous network.
9. Method according to claim 2, whereby the network is a partially synchronous network.
10. Method according to claim 1, whereby the number t of faulty devices is larger than n3 if all or a part of the faulty devices fail by crashing.
11. Method according to claim 2, whereby the number t of faulty devices is larger than n3 if all or a part of the faulty devices fail by crashing.
12. Method according to claim 1, whereby a transaction identifier is used.
13. Method according to claim 2, whereby a transaction identifier is used.
14. Method according to claim 1, using one of synchrony assumptions or timing assumptions.
15. Method according to claim 2, using one of synchrony assumptions or timing assumptions.
16. Method according to claim 1, using a part-protocol based on leader election.
17. Method according to claim 2, using a part-protocol based on leader election.
18. Method according to claim 1, using threshold signatures.
19. Method according to claim 2, using threshold signatures.
20. Method according to claim 1, whereby the number t of faulty devices is extended to a set T of sets comprising participating network devices.
21. Method according to claim 2, whereby the number t of faulty devices is extended to a set T of sets comprising participating network devices.
22. Method according to claim 20, whereby the participating network devices show hybrid failures reflecting a different structure of the set T or different thresholds t1, with i1, 2, . . . l.
23. Method according to claim 21, whereby the participating network devices show hybrid failures reflecting a different structure of the set T or different thresholds t1, with i1, 2, . . . l.
24. A computer program comprising program code means for performing the method for achieving agreement among n participating network devices to an agree-value in a network, the agreement arising out of a series of messages being sent and received by each participating network device, whereby the number t of faulty devices is less than n3, each participating network device, said method comprising the steps of:
(a) broadcasting to the participating network devices an init-vote message comprising an init-vote value;
(b) once having received one of n valid of the init-vote messages with init-vote values from the participating network devices and a signal from a failure detector, evaluating the received init-vote values to obtain a verification-vote value whereby the verification-vote value is an evaluating function of the received init-vote values;
(c) broadcasting to the participating network devices a verification-vote message comprising the obtained verification-vote value; and
(d) once having received n of the verification-vote messages comprising the same verification-vote value, deciding the agree-value to be equal to the same verification-vote value, or having received a signal from any failure detector;
(e) broadcasting to the participating network devices a signed verification-vote message comprising the obtained verification-vote value and a signature; and
(f) once having received n-t signed verification-vote messages, performing a fallback agreement protocol with an initial value that has the simple majority of the received obtained verification-vote.
25. A computer program device readable by machine tangibly embodying a program of instructions executable by the machine for performing the method for achieving agreement among n participating network devices to an agree-value in a network, the agreement arising out of a series of messages being sent and received by each participating network device, whereby the number t of faulty devices is less than n3, each participating network device, said method comprising the steps of:
(a) broadcasting to the participating network devices an init-vote message comprising an init-vote value;
(b) once having received one of n valid of the init-vote messages with init-vote values from the participating network devices and a signal from a failure detector, evaluating the received init-vote values to obtain a verification-vote value whereby the verification-vote value is an evaluating function of the received init-vote values;
(c) broadcasting to the participating network devices a verification-vote message comprising the obtained verification-vote value; and
(d) once having received n of the verification-vote messages comprising the same verification-vote value, deciding the agree-value to be equal to the same verification-vote value, or having received a signal from any failure detector;
(e) broadcasting to the participating network devices a signed verification-vote message comprising the obtained verification-vote value and a signature; and
(f) once having received n-t signed verification-vote messages, performing a fallback agreement protocol with an initial value that has the simple majority of the received obtained verification-vote.
26. A computer program comprising program code means for performing the method for achieving agreement among n participating network devices to an agree-value in a network, the agreement arising out of a series of messages being sent and received by each participating network device, whereby the number t of faulty devices is less than n3, each participating network device performing the following steps:
i) performing for a number of honest participating network devices that exceeds 2n3 an agreement protocol that comprises failure detection;
ii) performing a validation protocol, using detector means that validates whether agreement is reached; and
iii) deciding for the agree-value in the case that at least x of the participating network devices agree, where x is a number larger than t, or performing a fallback agreement protocol if at least one participating network device suspects that the agreement is not reached, the fallback agreement protocol producing the same agree-value value if at least one of the honest participating network devices has already decided for the agree-value.
27. A computer program product readable by machine tangibly embodying a program of instructions executable by the machine for performing the method for achieving agreement among n participating network devices to an agree-value in a network, the agreement arising out of a series of messages being sent and received by each participating network device, whereby the number t of faulty devices is less than n3, each participating network device performing the following steps:
i) performing for a number of honest participating network devices that exceeds 2n3 an agreement protocol that comprises failure detection;
ii) performing a validation protocol, using detector means that validates whether agreement is reached; and
iii) deciding for the agree-value in the case that at least x of the participating network devices agree, where x is a number larger than t, or performing a fallback agreement protocol if at least one participating network device suspects that the agreement is not reached, the fallback agreement protocol producing the same agree-value value if at least one of the honest participating network devices has already decided for the agree-value.