Abstract: A hashing database system that efficiently handles collisions comprises a list of data blocks divided into a plurality of stages, each of which is geometrically smaller than the preceding stage. The key of the data to be stored or retrieved (the "desired key") is hashed and, along with the stage number, used as an input into a staging algorithm to derive an offset into the list. One or more data blocks in the list surrounding the hashed-to data block are checked to determine whether the key field in the data block matches the desired key. If the keys match, then the desired data block is found. If the desired key is not found, then the hashed key is again used as an input into a staging algorithm along with the stage, and a new offset is derived and used as an index into the next stage of the index list. These steps are repeated until the key is found or the last stage is reached.

Abstract: Relatively dust-free air to cool electronic equipment, for example, is provided by apparatus which includes at least first and second rows of filamentary electrodes disposed in an air stream and aligned with its direction of flow. Alternate rows of electrodes are connected to respective electric potentials, the potentials and the electrodes being such as to create a net positive space charge between the rows. This causes dust particles in the air stream to acquire a positive charge and thus to move toward the more negative row(s) under the influence of the electric field set up by the potential difference between the rows. This, in turn, results in the creation of streams of clean and dirty air. These are then separated by a baffle having channels which are substantially aligned with the rows of electrodes. The clean air is directed into an enclosure housing the equipment to be cooled. The dirty air is discharged back into the atmosphere, e.g., back into the room in which the equipment is located.