Abstract: Systems, methods, and apparatus store and play licensed digital content in a plurality of files on a computer-readable medium. In addition, a plurality of dummy files are also stored on the computer-readable medium. The file names for the licensed digital content files and the dummy files are generated in a manner such that the licensed digital content files cannot be distinguished from the dummy files. The file names may comprise randomly generated characters, or sequential file names where the sequential file names are randomly assigned to the digital content files and the dummy files.

Abstract: A head enclosing gas hood for treating respiratory ailments is placeable over a patient's head for providing a gas, preferably oxygenated, to said patient. The treatment gas hood has a hood portion which is connected to a hood ring. The hood ring slides over a two-piece neck ring, the two-piece neck ring consisting of an upper neck ring and a lower neck ring retained in adjacent relationship. The hood ring slides over the two-piece neck ring and forms a sealing relationship therewith. The two-piece neck ring has a neck seal retained therein and has a sealing ring on the outer periphery thereof for engagement with the working surface of the hood ring. Ports may be provided for directing a flow of a gas into and from the interior portion of the hood where the individual's head is located. The neck seal provides an adequate seal between the neck ring and the individual's neck such that a pressurized environment may be created in the hood if desired.

Abstract: An oxygen head tent which is placeable over an individuals head for providing a gas, preferably oxygen, is described. The oxygen head tent has a hood portion which is connected to a hood ring. The hood ring slides over a two-piece neck ring, the two-piece neck ring consisting of an upper neck ring and a lower neck ring retained in adjacent relationship. The hood ring slides over the two-piece neck ring and forms a sealing relationship therewith. The two-piece neck ring has a neck seal retained therein and has a sealing ring on the outer periphery thereof for engagement with the working surface of the hood ring. Ports may be provided for directing a flow of a gas into and from the interior portion of the hood where the individuals head is located. The neck seal provides an adequate seal between the neck ring and the individuals neck such that a pressurized environment may be created in the hood.

Abstract: A field replaceable encoder including a slotted housing having a pair of passages therethrough essentially perpendicular to the longitudinal axis of the housing, is attachable to the frame of a machine having a rotatable shaft to which the encoder is to be mounted. Attached to the housing is an accurate stationary mask, the mask having slits which are aligned with the passages in the housing. The mask includes an accurately dimensioned aperture for locating the mask, and thus the housing, on a bearing on the rotatably mounted shaft. A pair of light sources and a pair of light detectors are mounted on opposite sides of the housing aligned with the passages and slits in the mask. A hub, to which is attached a rotating disc, is connected to the rotating shaft, the disc being mounted in the slotted housing so that interdigitated opaque and transparent portions align with the slits of the mask, and thus the light sources and light detectors.