This invention provides a high purity silica crucible having low impurity concentration in its inner portion, and its production method. Said machine also comprises at least one measuring device for measuring actual measurand values relating to actuation andor to fibre material. When an intruder blinds a camera lens using a cover, the security system can generate a warning by identifying the fact that the camera is blinded by the cover. A device receiving the request may transmit a copy of the data to the requesting device. In one example of a computing environment utilizing one or more aspects of the invention, a storage subsystem comprising a data object manager prepares for the anticipated request by pre-fetching data blocks from storage media into a cache.