Direct access storge devices (DASDs) or disk drives, once used in "high tech" applications, are currently in wide use, yet their users are seldom aware of the complications certain extreme environments may pose. To ensure satisfactory operation in the filed, disk drives must be manufactured under some of the most stringent cleanliness standards of any industry. Without these precautions, many disk drives could fail at the head-disk interface (HDI). Three of the main environmental factors that jeopardize good HDI performance are: corrosion of the head and disk materials which can reduce the performance of the magnetics, vapor condensation during thermal cycling of the drive which increases the possibility of a catastrophic failure, and reduced flying height of the slider over the disk in low pressures which can increase wear at the HDI. The challenge opf meeting these cleanliness standards is becoming more difficult as magnetic recording equipment becomes mroe ensitive to the presence of contaminants, e.g. the advent of pseudo-contact recording heads whcih operate at ultra low flying hights. This paper examines the details of environmental contamination problems, the techniques for their evaluation, and technology the disk drive industry has developed to solve for them.
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