Single Source. Single-source state exchange mechanisms such as Leader/Follower and Master/Shadow are par- ticularly well-suited for systems that are constrained to only benign faults. For this to be true, though, hosts as well as the network must be constrained to the benign failure class. When this is achieved, the Leader or Master can broadcast the definitive applications state without broadcasting any errors (i.e., all state that is transferred will be correct, but delivery is not guaranteed). In the Leader/Follower case, a leader is elected from a set of candidates and holds tenure until it fails. During its tenure, the Leader is the definitive source of state and broadcasts that state with sufficient frequency to meet system requirements. Detection of the Leader’s failure is simplified in time-triggered networks. All the Leader needs to do is to transmit a periodic heartbeat. When any of the nodes that are capable of voting for a new leader detect that the heartbeat has failed, they cast a vote for a new leader. If the threshold for electing a new leader is based on the total number of eligible voters rather than the total number of voters participating in any particular election, the voting mechanism itself can mask potential problems with inconsistent observations of the current leader’s failure. That is, if only a minority of the eligible voters observes that the heartbeat has failed, they cannot cast enough votes to elect a new leader. Some bandwidth can be saved if the state transfer acts as the heartbeat. In the Master/Shadow case, the current Master and all shadows form a priority ordered set. The highest priority fault-free participant in that set is the current Master. To save bandwidth in ARINC 659, there are Master/Shadow slots in the schedule that allow up to four nodes to use the same bandwidth. Using a mini-slotting protocol within those slots, the highest priority participant is allowed the first chance to transmit. If it doesn’t begin to transmit within it mini-slot, the next higher priority participant attempts to transmit, ... and so on through the fourth priority. For state exchanges, all the participants would send the required state in that slot using the same format regardless of the source. Thus, any receiver needing this state can use the data transferred in this slot without needing to know the source. This can accommodate participants with omission failures, but not manifest failures. A similar thing can be done for TTEthernet, with the add...
Single Source. Services for tasks in circumstances which meet the requirements of paragraph 3.10 of the Consultants’ Guidelines for Single Source Selection, may, with the Bank’s prior agreement, be procured in accordance with the provisions of paragraphs 3.9 through 3.13 of the Consultants Guidelines.
Single Source. Notwithstanding the requirements of Section 4.01(c) above, although two (2) or more vendors can supply the requisite Equipment and/or provide the necessary related services, the City may, in its sole and absolute discretion, upon written findings setting forth the material and substantial reasons therefor, authorize Funding Recipient to procure all or any portion of the Equipment on a single source basis from vendor(s) identified by Funding Recipient, provided that such Equipment would otherwise constitute Eligible Equipment and the vendor(s) thereof otherwise constitute Eligible Vendors. In such instances, Funding Recipient shall provide the City with the circumstances leading to the selection of the vendor, including the alternatives considered, the rationale for selecting the vendor in question and the basis upon which it determined the cost was reasonable.
Single Source. Equipment furnished under the terms of this specification shall be the standard product of a single manufacturer.
Single Source. A procurement where two or more Bidders can supply the required Product, and the Commissioner may award the contract to one Bidder over the other.
Single Source. Notwithstanding the requirements of Section 4.01(c) above, although two (2) or more vendors can supply the requisite Equipment and/or Vehicle(s), DDC may, in its sole and absolute discretion, upon written findings setting forth the material and substantial reasons therefor, authorize Funding Recipient to procure all or any of the Equipment and/or Vehicle(s) on a single source basis from vendor(s) identified by Funding Recipient, provided that such Equipment and/or Vehicle(s) would otherwise constitute Eligible Equipment and Vehicle(s) and the vendor(s) thereof otherwise constitute Eligible Vendors. In such instances, Funding Recipient shall provide DDC the circumstances leading to the selection of the vendor, including the alternatives considered, the rationale for selecting the vendor in question and the basis upon which it determined the cost was reasonable.
Single Source. Provide materials of a single manufacturer for systems specified.
Single Source. Services for independent monitoring of the RAP under Part D of the Project, and services for monitoring and evaluation, under Part C.4(ii) of the Project shall be procured under contracts awarded in accordance with the provisions of paragraphs 3.1 through 3.4 of the Consultant Guidelines.
Single Source. As the single source supplier for industrial computers on both the PV6 &L850 global engine programs, Nematron shall be informed of any request for deviation from the use of Nematron PC's. Nematron shall provide input with respect to deviations and have first chance at solving these issues.
Single Source. Funding The Contractor will:
