Transfer Descriptors Sample Clauses

Transfer Descriptors. A Transfer Descriptor (TD) is a system memory data structure that is used by the Host Controller to define a buffer of data that will be moved to or from an endpoint. TDs come in two types: general and isochronous. The General TD is used for Interrupt, Control, and Bulk Endpoints and an Isochronous TD is used to deal with the unique requirements of isochronous transfers. Two TD types are supported because the nature of isochronous transfers does not lend itself to the standard DMA buffer format and the packetizing of the buffer required for isochronous transfers is too restrictive for general transfer types. Both the General TD and the Isochronous TD provide a means of specifying a buffer that is from 0 to 8,192 bytes long. Additionally, the data buffer described in a single TD can span up to two physically disjoint pages. Although the scatter/gather capabilities of a single TD are limited, it eliminates most of the problems associated with forcing buffers to be physically contiguous including the possibility of superfluous data movements. Transfer Descriptors are linked to queues attached to EDs. The ED provides the endpoint address to/from which the TD data is to be transferred. The Host Controller Driver adds to the queue and the Host Controller removes from the queue. When the Host Controller removes a TD from a queue, it links the TD to the Done Queue. When a TD is unlinked from the ED and linked to the Done Queue, it is said to be ‘retired’. A TD may be retired due to normal completion or because of an error condition. When the TD is retired, a condition code value is written in the TD which allows the Host Controller Driver to determine the reason it was retired. Details of TD processing are dependent on the type of TD and are discussed in Sections 4.3.1 through 4.3.3.1.
View SourceView Similar (2)

Related to Transfer Descriptors

  • SERVICE LEVEL DESCRIPTION The Fund Accounting Agreement is hereby amended by deleting the Service Level Description attached thereto and replacing it in its entirety with the Service Level Description attached hereto.

  • Long Description (If Applicable Training to provide the knowledge, skills and abilities needed as a result of agency mission, policies, or procedures. . Training to acquire the knowledge, skills and abilities needed as a result of assignment to new duties and responsibilities when such training is not part of a planned, career development program (e.g., training provided to a staffing specialist who has been newly assigned to a position involving classification duties).

  • Service Descriptions Credit Card processing services: Global Direct’s actions to the appropriate card associations and/or issuers (e.g., Visa, MasterCard, Diners, Discover); settlement; dispute resolution with cardholders’ banks; and transaction-related reporting, statements and products. Debit/ATM Processing Services: Global Direct has connected to the following debit card networks (“Networks”): Accel, AFFN, Interlink, MAC, Maestro, NYCE, Pulse, Star, and Tyme. Global Direct will provide Merchant with the ability to access the Networks that Global Direct has connected to for the purpose of authorizing debit card transactions at the point of sale from cards issued by the members of the respective Networks. Global Direct will provide connection to such Networks, terminal applications, settlement and reporting activities. EBT Transaction Processing Services: Global Direct offers electronic interfaces to Electronic Benefits Transfer (“EBT”) networks for the processing of cash payments or credits to or for the benefit of benefit recipients (“Recipients”). Global Direct will provide settlement and switching services for various Point of Sale transactions initiated through Merchant for the authorization of the issuance of the United States Department of Agriculture, Food and Nutrition Services (“FNS”) food stamp benefits (“FS Benefits”) and/or government delivered cash assistance benefits (“Cash Benefits, ”with FS Benefits, “Benefits”) to Recipients through the use of a state-issued card (“EBT Card”). With respect to Visa and MasterCard products, Merchant agrees to pay and Merchant's account(s) will be charged pursuant to Section 5 of this Agreement for any additional fees incurred as a result of Merchant's subsequent acceptance of transactions with any Visa or MasterCard product that it has not elected to accept.

  • Topic Description Severability If any provision of this Agreement is declared invalid or unenforceable, then, to the extent possible, all of the remaining provisions of this Agreement will remain in full force and effect.

  • Investment Description Each Fund will invest and reinvest its assets in accordance with the investment objective(s), policies and limitations specified in the prospectus (the “Prospectus”) relating to such Fund filed with the Securities and Exchange Commission (the “SEC”) as part of the Fund’s Registration Statement on Form N-1A, as it may be periodically amended or supplemented and in accordance with exemptive orders and no-action letters issued to the Trust by the SEC and its staff.