Abstract: A chemical, biological, radiological, and nuclear weapons detection system is disclosed that comprises an array of spatially-disparate hazardous material sensors that all feed into a centralized system control center. This enables the embodiment to receive and coordinate in one place all of the hazardous material sensors spread over a wide area, and, therefore, enables an alarm to be quickly issued in the event of a real attack. The illustrative embodiment also incorporates a mechanism to reduce the probability that a false alarm will be issued. In particular, the illustrative embodiment requires that at least 2 stations report an alarm for the same hazardous material within an interval of time. This prevents a false alarm from one hazardous material detection station from issuing a false system-wide alarm. This is based on the assumption that a real attack is more likely to be detected by stations that are near each other than by stations that have no proximity.

Abstract: A paging method for information retrieval from broadcast disk systems is described. In response to a page request (e.g., a request for an item of data), the method selectively stores and evicts, in and from a fast memory, pages of data broadcasted by the broadcast disk system. The methods proceeds using a three-“color” labelling scheme, wherein the label assigned to a broadcasted page is based on how recently a given page was last requested. If a requested page is stored in fast memory, then the request is immediately served. If the requested page is not stored in fast memory, the request cannot be served until the requested page is broadcasted. While waiting for the requested page to be broadcasted, certain “somewhat-recently” requested pages are “prefetched,” wherein they are stored in fast memory even though there is no pending request for such pages.