Abstract: A digital content management system includes a host machine and a delivery machine remote from the host machine. The host machine sends validation agent software to the delivery machine, which executes the validation agent. The validation agent performs one or more tests or observations to determine whether the delivery machine has been compromised, and communicates the results of the tests or observations to the host machine. If the host machine determines that the delivery machine has not been compromised, the host machine sends digital content to the delivery machine, and a player module at the delivery machine delivers the content to the user according to an appropriate set of access rights. After delivering the content, the delivery machine deletes the content to prevent unwanted access to the content. The content can contain signals indicative that the content is legitimate, such as watermarks or bad code segments or sectors.

Abstract: A digital content management system includes a host machine and a delivery machine remote from the host machine. The host machine sends validation agent software to the delivery machine, which executes the validation agent. The validation agent performs one or more tests or observations to determine whether the delivery machine has been compromised, and communicates the results of the tests or observations to the host machine. If the host machine determines that the delivery machine has not been compromised, the host machine sends digital content to the delivery machine, and a player module at the delivery machine delivers the content to the user according to an appropriate set of access rights. After delivering the content, the delivery machine deletes the content to prevent unwanted access to the content. The content can contain signals indicative that the content is legitimate, such as watermarks or bad code segments or sectors.

Abstract: A digital content management system includes a host machine and a delivery machine remote from the host machine. The host machine sends validation agent software to the delivery machine, which executes the validation agent. The validation agent performs one or more tests or observations to determine whether the delivery machine has been compromised, and communicates the results of the tests or observations to the host machine. If the host machine determines that the delivery machine has not been compromised, the host machine sends digital content to the delivery machine, and a player module at the delivery machine delivers the content to the user according to an appropriate set of access rights. After delivering the content, the delivery machine deletes the content to prevent unwanted access to the content. The content can contain signals indicative that the content is legitimate, such as watermarks or bad code segments or sectors.

Abstract: A retrieval tool for retrieving a back pressure valve and tree test plug (generally, a check valve) has a spear formed as a solid ring at the bottom with free fingers extending upward. The fingers are resilient and have protrusions adapted to engage a retrieval groove in the check valve. A wedge ring is provided on the tool body to positively lock the fingers in radially outward engagement with the retrieval groove. The wedge ring is fixed to the body by a shear pin so that upon a predetermined axial force the pin shears and releases the wedge ring allowing withdrawal of the tool assembly, if the check valve is stuck in a tubing hanger or coupling.

Abstract: A wellhead retrieval tool assembly for retrieving a check valve has a spear formed as a solid ring at the bottom with free fingers extending upward. The fingers are resilient and have protrusions adapted to engage a retrieval groove in the check valve. A wedge ring is provided on the tool body to positively lock the fingers in radially outward engagement with the retrieval groove. The wedge ring is fixed to the body by a shear pin so that upon a predetermined axial force the pin shears and releases the wedge allowing withdrawal of the tool assembly.