Direct access storage device

Following a concise review of direct access storage devices, a treatise on the properties and electrochemistry of magnetically soft materials is provided by P. C. An-dricacos and L. T. Romankiw. The chapter is focused on the fundamentals of the magnetics and electrochemistry of Permalloy, a material which has similar importance in magnetic storage as has silicon in semiconductor devices. 

DMA (direct memory access) A method of transferring information directly from a mass-storage device such as a hard disk or from an adapter card into memory (or vice versa), without the information passing through the processor. 

Areas of pollution, clandestine laboratory operations and the wind drift of pollutants can be mapped by this technique. It can be a particularly powerful tool in forensic investigations because it is a non-intrusive device that can search the atmosphere around a suspected cite of illicit chemical manufacturing, storage, pollution or disposal without requiring direct access to the subject site. 

Air pressure discharge vehicles are able to blow directly into the storage bunker, which should be as described in section 17.3.4 and fitted with a filter to remove dust from the conveying air. The filter should be weatherproof and watertight and should discharge the collected dust into the bunker. A pressure relief device should be fitted as well as the usual accesses and safety features. 

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